Hi All,

Like the rest of you, my car's mileage has basically sucked since the beginning. I even tried driving it at 65 mph in sixth gear with the windows up (albeit with the air on) from Porterville to Los Angeles last week, and still got a relatively abysmal 17 mpg.

However, several days ago, I found out that we are able to disable the DSC AND TCS by pressing and holding the DSC switch for several seconds (DSC OFF light comes on, followed by the little skidding car a few seconds later). Now, being a sports car purist at heart, I decided to turn these features off for the next month every time I got in the car in an effort to get more insight as to the car's true unassisted capabilities.

Well, two things happened. To preface the first item, I should tell you all that the onramp to the freeway by my house is metered in the morning with a red/green light system (those that live in L.A. will know what I'm talking about immediately). Anyway, you drive up to it while red, stop and wait for it to turn green, and then you are allowed to enter the freeway. Anyway, in the morning, on the way to work, I always like to smash the pedal on green and give the car a morning spurt up to about 90 before merging onto the freeway (some days, this is a requirement). After doing this every day, one starts to notice that the car is always at about the same spot when reaching the 90 mark.

Yesterday, when entering the freeway, with all traction off, the tires spun on takeoff (expected) and the car surged forward after hooking up (not expected). Then, upon reaching my normal mark, I looked down to find the speedometer reading in excess of 100 mph!! I immediately exited the freeway and went back to the same onramp and repeated the process to find that, WOW, the car reached 90 mph much sooner than the standard mark! I went back and repeated the process a third time (late for work, f*ck it, I'm busy) with all the traction systems on and hit the standard mark at 90 mph.

SOOOOOOO, faster acceleration translates as more horsepower, YES? What I would like to know is if those that put this car on the dyno knew about disabling the ENTIRE traction control system??

Second thing that happened is that previously, upon reaching work after a couple days, I realized that the gas gauge had not moved as much as it normally does (typically time to fill up, but tank still reads half full); well, I did a test here as well. Being careful to disable the traction system every time I got in the car through today, I have found that my average city/highway gas mileage has increased by 50%!! Before, it was averaging 15 to 16 mpg. NOW, it's at 24!

Is it the fact that the traction control system is off or that the car has over 5000 miles on it? I say, go out and disable the traction system for a few days and find out for yourself. Happy motoring!!

My baby:

Very interesting ...... Got to try it!!!! Thanks for the useful posting we need more of that than the other kind.

like your attitude, living on the fault line. sweet picture of your 8. from the threads i've read, the traction control was turned off during testing. don't know but wouldnt mazda put an asterisk next to the mpg stating *with traction control turned off or words to that affect? ah whatever you may be on to something.

Well, here's the thing. There are two levels of traction control that would need to be turned off. If you press the DSC button and release it immediately, it disables the DSC system only. Most people know this. I expect that what the testers did was the same.

However, in order to COMPLETELY disable the system, you must press and HOLD the button for a few seconds, which then disables the TCS system (the little skidding car). This is separate from the DSC system. I am not sure that the testers even knew about this, since it's not even mentioned in the manual.

If any of the testers are out there, could you please confirm whether or not you knew about this option?

This has already been brought up before a few times, but yes. It was fully disabled.

Originally posted by Genom
This has already been brought up before a few times, but yes. It was fully disabled.

Really? I'd really like to see the posts about this. Can you point me to them?

Are you one of the people that tested the car? If so, I'd be curious about how you knew to disable the secondary system so early on when it's not in the manual. In addition, are you able to account for increased mileage with the system disabled? Inquiring minds want to know!!

Rudenauer, Mazda has downgraded the HP as I hope you are aware and is offering owners that signed a sales contract b4 Aug. 26 $500 back and free maintenance for the life of the warranty. So as far as I'm concerned there is no more hp problem and hopefully RX Magazines tests in their first issue will confirm my assumption.

However I believe that you have formulated a very promising theory, if someone else will not do it I will, when my car arrives of course, drive 250+ miles in a straight line with DSC on. Then fill up again on the same brand/octane and drive back on that same line with DSC off and ill see what happens. With that said I believe that it's logical to assume that having your breaks applied in minute levels very often by the DSC system will yield a 7Mpg difference.

Well having a canadian GS model with NO DSC and NO TCS I would like to welcome you to MY world :D

My world of spinning tires, power slides on corners and great gas mileage :)

f1michel may chime in as well, he has the EXACT same car as me (down to colour) and we both get similar mileage.... we seem to be the only 2 on the board.

Maybe it's because of the lack of traction aids!

Originally posted by Rudenauer


Really? I'd really like to see the posts about this. Can you point me to them?

Are you one of the people that tested the car? If so, I'd be curious about how you knew to disable the secondary system so early on when it's not in the manual. In addition, are you able to account for increased mileage with the system disabled? Inquiring minds want to know!!

It's been posted here for a long time many times. Not even sure how I first found out but I knew before I got my car 7/19.

This seems like a good idea for a road trip to tampa. HMMMMM
All I need now is the car

If you look at the dynos, the power is fine under 6250rpms, but it is above that the power falls short. So if your theory is true then, that means that the DSC or TCS doesn't turn on below 6250. That does not sound very likely. And I'm sure Mazda talked with their engineers first before deciding on taking on the buyback program and bad publicity. Butt dynos aren't very accurate. Different temps, different traction on the road that day, and there's a psychological factor working there too. People have sworn they felt power increases with mods on other cars before only to see that they lost power when dynoed.

Guys I have an automatic Rx8 so the horsepower doesnt meanmuch to me. I love DSC and I think it is the reason why I can getaway with so many dirty moves in this car. But if turning it off will mean I get 3 more miles with each gallon I am all for it. So if i disable both of the electronic driving safety features my mileage will go up? Are you positive?

Originally posted by Rudenauer
Really? I'd really like to see the posts about this. Can you point me to them?

Are you one of the people that tested the car? If so, I'd be curious about how you knew to disable the secondary system so early on when it's not in the manual...I did a quick search for you and found about 50 threads which talks about how to fully disable the DSC.

The earliest thread I bothered to read all the way through was from 4-17-03 where Hercules states: (http://www.rx8forum.com/showthread.php?s=&threadid=4157&highlight=off+AND+DSC)
Originally posted by Hercules
I believe the car is drive by wire as is the case with most upcoming cars, most namely in the BMW Z4.

The DSC unlike other systems, can be completely disengaged. When you hit the button the first time it will only activate under heavy braking (saving you from a skid), and if you hold it down for 5 seconds, it will completely turn off.

I would also like to quote myself from 8-18-03 in a huge thread about dyno results called R&D here (http://www.rx8forum.com/showthread.php?s=&threadid=7976&perpage=40&highlight=DSC&pagenumber=7):
Originally posted by Pelucidor
The other very common question is 'was the DSC/Traction turned off during the dynos'. The answer is YES, in at least all the dyno tests I know about. No doubt this will be revisited in a page or two...

Just because something is not in the manual doesn't mean that you should criticize others for knowing about it before you...


However I will say that if repeatable by others your name and novel way to improve fuel economy will live in legend on this site. I will be trying it out next week...

That bring up another topic of concern. Wouldn't tire wear become worse? Hence having to replace the tires sooner? And tires arn't cheap, at least not for good performence one such as Y or Z rated ones.

I am going to give it a whirl this week, will know by the weekend. If this is the case then there is a problem that needs fixing.

I hope your right because you did name the thread hp and gas problem SOLVED

Rudenauer: also about your preformance increase - anybody who drag races (not me) will tell you that disabling TC and DSC will have a big improvement in numbers. When you come on the gas hard from a standstill the DSC is probably easing things off a little to prevent too much tire spin. But some tire spin is good for acceleration runs in a RWD car and that is why your 'trap speed' is higher (100mph instead of 90mph) at your mark point.

I cannot explain your vastly better fuel economy however and am intrigued - definitely doing the test...


Tronics: why would tire wear become worse without DSC? Most cars don't have DSC at all you know (including the base RX-8). Unless of course you INTEND to try to do masssive wheelspins/burnouts (e.g. 6000rpm+ clutch dumps) at every opportunity, in which case I agree tire wear will be worse.

so,

if it is true that the power is better and the gas milage is better and i would like to go this route......then to disable it is the way to go. now i have noticed that when you shut off the car the system resets and you have to turn off the dsc again on the next start up. is there a way to keep it off until it is wanted back on? is there a mod or any way that we can do this without having to hold the button every time i start the car?

thanks

gtreat pic.. ..woah wait great color.. hehe


thanks for the info ima give me of a look into it.. igot 13.5 mpg on ym first tank but the fact its my first stick prob played a roll soemmewhere.

Originally posted by pelucidor
I did a quick search for you and found about 50 threads which talks about how to fully disable the DSC.

The earliest thread I bothered to read all the way through was from 4-17-03 where Hercules states: (http://www.rx8forum.com/showthread.php?s=&threadid=4157&highlight=off+AND+DSC)

I would also like to quote myself from 8-18-03 in a huge thread about dyno results called R&D here (http://www.rx8forum.com/showthread.php?s=&threadid=7976&perpage=40&highlight=DSC&pagenumber=7):

Just because something is not in the manual doesn't mean that you should criticize others for knowing about it before you...


However I will say that if repeatable by others your name and novel way to improve fuel economy will live in legend on this site. I will be trying it out next week...


How do you turn it back on? Can you do it while you are driving?

Are the DSC & TCS functions in the same computer that does spark timing, etc? Its conceivable that if one computer is doing both engine control and traction, there could be a "real time" problem, that is, the computer needs to make adjustments to multiple systems at the same time and gets "behind schedule". Its a long-shot, but could definitely affect performance.
cc

Originally posted by mmjames



How do you turn it back on? Can you do it while you are driving?

Once fully disabled only a restart of car will turn back on.

I am cautiously excited about the increase in mileage.

Not sure why turning the Traction Control off would help it, but it would remove a very important safety feature from our normal driving routine, for the sake of economy.

I'll tell you right now that turning it off is not what helped your gas mileage. I have a base model - no DSC or TSC, just a regular ol' engine driving wheels. I get around 15 MPG always. haven't yet managed to get anywhere close to 20, let alone 24 (did you confirm this by emptying your tank, or just eyeballing the dial?).

As for the horsepower, it is a measure of the engine power, and the power delivered to the rear wheels. DSC and TSC use braking of the wheels to ensure no slip. in other words, what should happen (I'm not saying this is necessarily true on the test beds that are used) is that the DSC should never engage during testing, regardless of whether it is on or off, since the test bed should never cause the wheels to spin. It's like ABS, except it engages when you're accelating (or turning) - it will only engage when it detects slipping tires, therefore loss of traction. ergo, it should never engage during a test.

If this is true, let's do a poll of users to find a trend on whether driving without DSC/TC will yield better fuel efficiency/performance. The poll would ask who has the base 6MT model and what is their mileage so far as all base models do not come with DSC/TC.

Originally posted by meat
It's like ABS, except it engages when you're accelating (or turning) - it will only engage when it detects slipping tires, therefore loss of traction. ergo, it should never engage during a test.

Could it detect that there's a difference between front wheel and rear wheel speeds?

Originally posted by meat
DSC and TSC use braking of the wheels to ensure no slip. in other words, what should happen (I'm not saying this is necessarily true on the test beds that are used) is that the DSC should never engage during testing, regardless of whether it is on or off, since the test bed should never cause the wheels to spin.

Not true - some older traction control systems only used the brakes, but many often had a mechanical implementation of a method to reduce throttle as well (even Ford's TC on the 95-96 Contour did this). Nowadays, with drive-by-wire throttle systems, the DSC and TC systems DO reduce throttle and possibly also timing to reduce power going to the rear wheels. The RX-8 DSC and TC systems DO use throttle and timing control in addition to brakes.

Regards,
Gordon

Wing -- What kind of mileage are you getting?

22-20.5MPG NEVER had anything under 18MPG

All city would be 19MPG, my best was a long highway trip 22.5MPG

Can't get better than that it seems, I did hit redline a few time in that good tank.

This last tank I've been hammering it all the time and it seems like I'm on track for 19MPG (all city).

Hey guys, he did menchen that he had over 5,000 miles. Could it possibly be the ecu finally allowing the engine to run at its full potential with the DSC & TCS off? Rudenauer, could you do a couple dyno runs with DSC & TCS on and off and post results?

I just did a quick test for freeway driving mileage. Round trip 94.5 miles on freeway. I got a record 19.4 MPG. After 1600 miles I haven't gotten any better that 16 MPG.
I will try the traction shut-off and post results.
Thanks for the suggestion.
My tail pipes still seem very sooty. Does anyone else have the same?
This week I'm going in for a 1000 mile check-up. My Mazda dealer has advised me that the oil change is not covered under warranty. This seems wrong to me.
For a company ready to buy back my car at my choice, you'd think they would easily cover an oil change for free.

Ok guys, like wing said we both have the exact same car, bought in 2 different provinces and we basically get the same fuel economy. I have no idea if DSC and all traction control makes it worst but it seems logical that if you drive it real hard most of the time it will hurt the mileage using the DSC. If you drive it moderate or easy i don't see how it affects the fuel consumption since there is no wheel spin and slide involved.

I am revving up my engine for the next tankfull, (filled up yesterday) and i will see what sort of mileage i get. I am now at close to 6000Km on it and it drives fantastic without the traction control. Up here it will be valuable during the (very)cold season but besides that time i really don't care much for it. (a good thing since i don't have it :-) )

I cannot comment on the DSC full off mileage, because I just tried it today. The car did seem to have much more punch over 6000. But I CAN testify to the milage - I have been keeping track for the last 4000 miles, and have been averaging 17.8 with DSC ON. I will start the DSC full off soon - but I know I will have a hard time keeping it on the road (I have a very heavy foot).

Don't worry, this car is VERY fun to drive without any help from electronics. Hell you might even become a better driver , just learning to have your right foot do the traction control.. :-))

Filled up today and started running with DSC full off. So far about 75 miles, should know in a couple days.

I did find one problem with turning it off, after getting used to it always being on and correcting for a heavy foot in the turns. When trying to accelerate from a stop at an intersection and shifting into second 3/4 into the turn your backend will whip out in a heartbeat. And even though you easily beat the BMW 330 to the next light, you didn't look so good doing it. And the surprise of it will make your heart race just a little. ;)

That is either a BIG turn or an early shift - I usually don't hit 30 until I am out of the turn.

Originally posted by FEBtch
That is either a BIG turn or an early shift - I usually don't hit 30 until I am out of the turn.
Probably a little of both Eight lane wide intersection and shifted around 7K.

Originally posted by Gord96BRG


Not true - some older traction control systems only used the brakes, but many often had a mechanical implementation of a method to reduce throttle as well (even Ford's TC on the 95-96 Contour did this). Nowadays, with drive-by-wire throttle systems, the DSC and TC systems DO reduce throttle and possibly also timing to reduce power going to the rear wheels. The RX-8 DSC and TC systems DO use throttle and timing control in addition to brakes.

Regards,
Gordon

You are right on this one Gord.
I was intrigued after reading the post on this.
I admit I am being a bit of an insomniac tonight ( OK, so it's almost 4 a.m. here!)

I have not turned off the DSC completely up to now, just the first stage a couple of times.
Car was in break in mode mostly, and I figured the difference between the short push, and holding the button for complete disable would not feel much different.
So, went for a spin. needed to buy smokes anyway ( used my Zippo as my radar detector is plugged into the place where my cigarette lighter USED TO BE!) {dig}

Anyway, to cut to the chase:
1) It has a HELL of a lot more power with it completely off.
There is a marked 1/4 mile on a back road about 5 minutes from my house. I live at the edge of the city, and paved secondary roads are close.

At 3:30 a.m. the traffic is non-existant, so I hope people will not think of this as "street racing"
First time I have done hard burn-out style runs on this car so far.
Took a stop watch ( it is a big one I wear around my neck as a soccer ref). I did my clutch drops at 6,000rpm and on the non-DSC runs I used moderate clutch slip to achieve some smoke without the rear end sliding out.

Did 3 runs with it on the first disable mode (DSC light warning):
15.5
15.4
15.2
Average: 15.36
I am probably within a couple of tenths accuracy manually running a stop watch..

Turned the DSC completely off (car on wavy tracks light on the dash).
Drove at 80kmh/3000rpm for about 3 clicks to cool the engine off.
Tried again:

15.1
14.8
14.9
Average: 14.93

Now, I grant this is NOT the same as a real track, with a tree, and perfectly accurate time equipment.
Still, I can see almost a half second improvement.

Also, with it right off, there is a definite feel of more power on the "butt dyno" above 5,000rpm.
Common belief is that it takes about a 10HP gain to feel any difference, so that sounds about right, as I DID feel that it is faster. My butt dyno guesses that it is putting maybe 15 or 20HP more down with the DSC right off.

It did not feel "snaky" in hard cornering under power. There is one corner on that road that is a fairly tight bend.
I have never been able to get the RX-8 to four wheel drift up to now, as I have had the DSC on, and it does work in conditions like this.

I was able to achive a drift in 2nd under hard power. No fuss, it was perfectly predictable transition from traction to slide with no surprises.
I could modulate the oversteer with throttle and recover quite easily.

So, unless you are on really crappy road conditions, it seems to me that turning this off almost all the time is the best thing to do for most people..

As for gas mileage, this week shall tell.
My mileage has been pretty predictable and constant so far, so if there IS a difference, I will likely see it..

I agree most here should be / are able to drive a car such as this without computer assisted aid in keeping slides under control. For winter or rainy weather I think it's a good thing to use - just in case.

Interesting posts from everyone. Makes for great reading. Thanks.

As a side FYI, I got 21.4 MPG on the highway....a 300 mile trip (yes...running on fumes)....the second long trip was shorter about 220, and still got 21.1 MPG. I filled up after each trip at the same station, on the same pump. Not truly scientific, but a good indication of potential. I have not gotten (even is city driving) anything less than 17 mpg, but haven't been real aggressive with RPMs (usually shifting at about 6k). Good luck on all the tests. I'm going to try the butt dyno later today with TCS off too.

If the DSC/TCS is a mileage/performance killer, wouldn't it be true that anyone that has a base RX-8 (not equipped with DSC) would get better mileage?

So, here's an interesting question.

If when you COMPLETELY turn off the DSC the Traction Control light, lights up as canzoomer has mentioned. Is it REALLY REALLY TRUELY TRUELY disabled? I mean come on, the light is on, the DSC is OFF, but what about the TCS??

Welcome to my world guys, I have a GS, no TCS no DSC, the car is plenty damn fast, and my gas mileage as mentioned is in the 20-22MPG range, no lower than 18-19 even in the city!

And it is fun to drift, just don't over compensate like I did once and go into a sliding ballet.

Is there nobody on here with MAzda engineering who can confirm that this MAY be the issue, or exclude it from the possibilities?

i,m like Wing here, car has no traction gyzmo, rides like a bullet and is so much fun to drive i'm at 6000KM sharp in 35 days.

Why pay 3 gran extra for a car that's less .... :-)

Kidding guys

another point is the way the engine is set up to deliver fuel. According to my Yamaguchi book, if you keep the RPM's below 3500 when you shift you will use only one injector and conceiveably less gas.

Originally posted by T-von
Hey guys, he did menchen that he had over 5,000 miles. Could it possibly be the ecu finally allowing the engine to run at its full potential with the DSC & TCS off? Rudenauer, could you do a couple dyno runs with DSC & TCS on and off and post results?

T-von,

I will try to get this car to a dyno sometime next week. I am extremely interested to see what kind of power variance (if any, a tip of the hat to skeptics) the car is putting out with the system on and off.

Originally posted by canzoomer


I was intrigued after reading the post on this.

Anyway, to cut to the chase:
1) It has a HELL of a lot more power with it completely off.

I can see almost a half second improvement.

Also, with it right off, there is a definite feel of more power on the "butt dyno" above 5,000rpm.
My butt dyno guesses that it is putting maybe 15 or 20HP more down with the DSC right off.

I was able to achive a drift in 2nd under hard power. No fuss, it was perfectly predictable transition from traction to slide with no surprises.
I could modulate the oversteer with throttle and recover quite easily.

As for gas mileage, this week shall tell.
My mileage has been pretty predictable and constant so far, so if there IS a difference, I will likely see it..

So Canzoomer, if your mileage improves, do you think that you might rethink your decision? :)

What is strange is that we pay extra for those features and it seems better times are if they are off. Something else to consider.

Simple question How do you turn the DSC and TSC back on, while driving. Must you turn off the car first each time?

Originally posted by mmjames
What is strange is that we pay extra for those features and it seems better times are if they are off. Something else to consider.

Simple question How do you turn the DSC and TSC back on, while driving. Must you turn off the car first each time?

Yes, you must turn the ignition off if you disable them both to get them re-enabled.

If you only turn off the DSC then you can re-enable it while driving.

Is there anyway you can completely turn the DSC and TSC off for good, so you don't have to bother with it the next time?

Originally posted by RodsterinFL
another point is the way the engine is set up to deliver fuel. According to my Yamaguchi book, if you keep the RPM's below 3500 when you shift you will use only one injector and conceiveably less gas.

3750RPM :D After that all 3 injectors are on!

I just filled up again, having used 3/4 of a tank with the DSC and TC turned completely off the whole time. The gas mileage was indistinguishable from that which I've been seeing all along: 15.5mpg.

I have 1200 miles on my car and on the avg. with getting on the throttle occassionally. I am getting 22.471 mpg with the DSC & TSC ON. Mostly city driving with a few Hwy. I have not tried it yet with it all off.

Originally posted by Wing


3750RPM :D After that all 3 injectors are on!

Actually, the injectors work at the same intervals as the ports. 2 injectors (1 for each rotor) up to 3750 which is when the secondary ports open and the secondary injectors come into play. So that's 4 injectors until 6250 when the auxilliary ports and extra injectors are activated.

idle - 3750rpm 2 inj
3750 - 6250rpm 4 inj
6250 - fuel cutoff 6 inj

Remember that the standard power engine only has 4 ports and 4 injectors.

Sport Package M/T, Sunlight Silver, 1950 miles

Very interesting posts within this 'thread'. I also have begun driving with the DSC/TCS "off", disabling the 'system' during the short idle before driving. Disabling isn't a 'habit' yet, but I almost always remember to turn it 'off' before driving away.

All things considered, there are many variables which will affect my mileage. However, I refilled my tank (6.25 gallons) this morning to check MPG after driving 138 miles with DSC/TCS 'off', and . . I DID get the 'highest' MPG I've ever gotten. A bit less than 22 MPG . . . which is not great, but higher than the roughly average 19.5 MPG I HAVE been getting.

I seem to be getting slightly better MPG using Shell, and I'm now using Shell 89 octane 'mid-grade'. This MAY help MPG a bit, but also may be that sales hype is affecting my mind. And because we are nearing the Fall season, I've been using less A/C (more open window). This probably helps MPG. And because the engine torque is relatively flat, I've been shifting more within the 2K - 3K RPM range instead of the 4K + range. (Doesn't seem to be necessary to accelerate in order to get into the 'torque range' like in a piston engine.) And, the outside air temperatures are cooler, which ALWAYS benefitted my relatively underpowered Dodge Stratus.

However, I have become more familiar and comfortable with my '8', and am driving with more assertiveness than I had been during the first 1K + miles. There DOES seem to be more available power and my car seems to have more . . . zip. Whether this is because of DSC/TCS being 'off', or having to do with 'break-in' of engine and associated parts, or having something to do with programmed 'mapping' changes, I don't know.

The bottom line. For whatever reasons, I've experienced better gas mileage and what feels like slightly more power during my obviously very short trial period of driving with DSC/TCS 'off'. The window sticker from my car states "highway MPG . . 24". I'll continue driving with DSC/TCS 'off' . . hoping . . I may achieve that 24 MPG some day in my '8'.

i just don't see the co-relation btw. milage/ dcs, tcs systems. Granted that dcs uses the brakes (and throtle/timing?) it would not affect the avg. mialege so much, from 17 to 21+ ... as far as power goes, it is all psycological, other wise mazda would have said something about it instead of offering 'free' stuff and buy backs, as dishonest as those b****ds are, they would find anything as an excuse, and if they didn't use it is because it is not a real power problem solver.
The real thing to think about is that again you mentioned that you have 5000 miles already in the car.. does anyone else that have over 5k of miles notice a mileage change or even power change in their car?..

sorry but for someone considering a buyback, this seems a bit too easy to just "fix the problem" of both power and mpg.

Yup, too good to be true. Oh well.

I just finished a tankful with the DSC fully off each time I started it.

No appreciable difference. I got 16.2 liters per 100 kilometers.
Mainly city driving, easy shifting. I generally shift 1,2 the 4 or 5th gear.
I pop in the cltuch, go into neutral and idle when decellerating to lights and stuff.

Glad I sent my letter in.

Just from personal experience using Shell gas, I do have a '98 Corolla, and tested during the summer their actual claims for more mpg.

Now, I drive real assertive. I jackrabbit greenlights, hit 75-80 on the freeways, etc. I don't drive a manual because I did get a 6 CD changer and driving stick doesn't make sense in So Cal traffic.

Now, my car holds 13.2gallons. Even when I ran with Arco, Chevron, Mobil, etc., with 50/50 driving on city and highway, I've been able to get mileage between 280-330 consistently. I always push til the gas indicator lights up.

I switched to Shell with similar driving style and similar driving routes with the 50/50 driving city/highway. Now, my mileage is consistently between 320-375.

I duplicated the test over a month just for reassurance to see if Shell gas was worth the extra $0.03 more per gallon. The results are still virtually the same, and even when I do hit the 280-300 mark with Shell, the tank still indicates just under 1/4 tank of gas, compared to the Gas light flashing with other types of gas and similar mileage.

I don't work for Shell, but I do recommend exploring this option. Even the extra 20 miles per full tank is worth it.

Originally posted by R32
Now, my car holds 13.2gallons. Even when I ran with Arco, Chevron, Mobil, etc., with 50/50 driving on city and highway, I've been able to get mileage between 280-330 consistently. I always push til the gas indicator lights up.

I switched to Shell with similar driving style and similar driving routes with the 50/50 driving city/highway. Now, my mileage is consistently between 320-375.

R32 (and others on this thread): I appreciate what you're saying and I'm playing around with Shell a bit to see if their claims are true. However, to add real validity to the numbers we need to be consistent in how we're measuring mileage. I'm not the first to post this, but we need occasional reminders. Running till the light comes on and seeing how many miles you went allows too much uncertainty in the precise mpg analysis.

For those who aren't doing so, here's what you do. Top off the tank (make sure it's really topped off.) Set your trip odometer to zero. Drive around, the lower you run the tank the better. Top off the tank again (make sure it's really topped off.) Note how many gallons it took on the second fillup. Divide miles on your odometer by gallons on the second fillup, that is your mpg. Report it to the forum. You should be accurate to a decimal place or so. Reset odometer to zero and repeat the process.

If we really want valid analysis of what's going on, everyone needs to remove subjectivity (like, it's half full so I got like 15 mpg.) Let's be consistent in how we're doing this. There are too many variables to start adding more of our own. :-)

I appreciate the tip, but now with college starting again (already 3rd week) it's going to be a lot of 90/10 city/highway.

I'll see what I can do.

Needless to say, I was already convinced when the I hit the 260mi mark with a quarter tank. 260mi on other gas was clearly near E.

Originally posted by R32
Needless to say, I was already convinced when the I hit the 260mi mark with a quarter tank. 260mi on other gas was clearly near E.

I'd kill for 260 at 1/4 full. The best I've done is 240 down to the warning light, which came out to 18.1 mpg when I refilled.

Just refilled after using 87 octane shell gaz and giving it a fair ride, using all 6 speeds all the time and shifting at 6k or just about.

14.06 L perr 100 k or 16.79 mpg. By far my worst tank and i'm at 6100 Km. Of course it was at the dealer today and they put 45KM on it testing whatever i told them wasn't right. ( cruise,AC, alignment, front brakes) all minor stuff. i'm sure the mechanic didn't shift it at 3K !

BTW, there nothing wrong with EVERYTHING i reported !!! I didn't laugh at him but told him he's probably get a service note pretty soon about all my minor complaints... i was their 1st ever RX8 to service since i was their 1st buyer and have over 6K in 5 weeks.

First tank (87) down with TSC/DSC off.

214Mile/12.3Gals=17.39 ! Best yet by over 1 MPG. I even forgot to turn it off a couple times and I drove the piss out of it every now and then. No grandma driving at all.

I wonder if the ECU map is messing with the DSC too, causing low mpg. :confused:

First tank (not even a complete one) with all turned off.

I had 47 miles on the tank before folllowing your advice. I just got gas last night and got 18.11 mpg in my regular town run where I was getting 16.5 mpg on the last 3 tanks prior. THis definitely makes a difference.

This is also in line with my last two cars' mileage. It is harder for us to compare mileage all driving different places and distances and of course with different conditions - some highway, some street runs, etc. My previous cars BMW 328is got 19-20 mpg and the MIllennia S 17-18 mpg on the run I refer to in the RX 8 above. THis is not that different.

SOmeting else to consider - using regular gas made mine run better (smoother) the first tank of regular I DROPPED to 14 mpg. but it quickly improved. I know I cannot MAKE any of you switch to regular gas but I cannot emphasize enough the difference it made on my engine. THe thing acted like it was choking before on 91. Like it was bogged down all the time. Then with regular it was as if it became free rolling (emergency brake off!!!) I keep reading where people used regular and their engines would barely run or started knocking hard, etc. I have a difficult time with that with all having the same engine and all.

ALso. according to the tech info on our engine, we only use 1 injector up to 3500 RPM and 2 beyond up to about 6000 - harder driving obviously uses more. SO I am training myself in town to shift throught the first three gears VERY quickly to force that 1 injector only scenario. THis of course being when I want to be conservative

Originally posted by RodsterinFL
using regular gas made mine run better (smoother) the first tank of regular I DROPPED to 14 mpg. but it quickly improved. I know I cannot MAKE any of you switch to regular gas but I cannot emphasize enough the difference it made on my engine.

ALso. according to the tech info on our engine, we only use 1 injector up to 3500 RPM and 2 beyond up to about 6000 - harder driving obviously uses more. SO I am training myself in town to shift throught the first three gears VERY quickly to force that 1 injector only scenario. THis of course being when I want to be conservative



Same experience here, Rod, both with the 87 octane and the injector scenario. I figure the least efficient speed to drive is that which the second or third injector has just kicked in; like another mph slower it would cut off. Put another way, the most efficient driving is as fast as you can go before the next injector kicks in. Don't know if this is true or not, maybe someone can weigh in. Unfortunately, at highway cruising in 6th this means 70 mph. I just find it hard to cruise that speed in the '8; the damn thing just wants to go 80. :D I'm using cruise control a lot now to increase efficiency further.

Originally posted by Rudenauer
Hi All,

Like the rest of you, my car's mileage has basically sucked since the beginning. I even tried driving it at 65 mph in sixth gear with the windows up (albeit with the air on) from Porterville to Los Angeles last week, and still got a relatively abysmal 17 mpg.

However, several days ago, I found out that we are able to disable the DSC AND TCS by pressing and holding the DSC switch for several seconds (DSC OFF light comes on, followed by the little skidding car a few seconds later). Now, being a sports car purist at heart, I decided to turn these features off for the next month every time I got in the car in an effort to get more insight as to the car's true unassisted capabilities.

Well, two things happened. To preface the first item, I should tell you all that the onramp to the freeway by my house is metered in the morning with a red/green light system (those that live in L.A. will know what I'm talking about immediately). Anyway, you drive up to it while red, stop and wait for it to turn green, and then you are allowed to enter the freeway. Anyway, in the morning, on the way to work, I always like to smash the pedal on green and give the car a morning spurt up to about 90 before merging onto the freeway (some days, this is a requirement). After doing this every day, one starts to notice that the car is always at about the same spot when reaching the 90 mark.

Yesterday, when entering the freeway, with all traction off, the tires spun on takeoff (expected) and the car surged forward after hooking up (not expected). Then, upon reaching my normal mark, I looked down to find the speedometer reading in excess of 100 mph!! I immediately exited the freeway and went back to the same onramp and repeated the process to find that, WOW, the car reached 90 mph much sooner than the standard mark! I went back and repeated the process a third time (late for work, f*ck it, I'm busy) with all the traction systems on and hit the standard mark at 90 mph.

SOOOOOOO, faster acceleration translates as more horsepower, YES? What I would like to know is if those that put this car on the dyno knew about disabling the ENTIRE traction control system??

Second thing that happened is that previously, upon reaching work after a couple days, I realized that the gas gauge had not moved as much as it normally does (typically time to fill up, but tank still reads half full); well, I did a test here as well. Being careful to disable the traction system every time I got in the car through today, I have found that my average city/highway gas mileage has increased by 50%!! Before, it was averaging 15 to 16 mpg. NOW, it's at 24!

Is it the fact that the traction control system is off or that the car has over 5000 miles on it? I say, go out and disable the traction system for a few days and find out for yourself. Happy motoring!!

My baby:

I sent you a P/M

I have a base model with no options - I mean nothing. I was considering returning mine for one with more options, but after hearing and reading about this whole TCS and DSC problem with speed and MPG - I think I am going to keep my base model with nothing on it.

I have heard of TCS and DSC slowing cars down.

I'm hoping that with some mods, no options, lighter tires, none of that other equipment to weigh me down, I may just get the speed up there!!;)

Just finished a full tank with DSC/TC full off. I've got 2600 miles on my GT now, using 87 octane. Since 2000 miles my mpg has been slowly increasing from 15 up to 18.1. Now with TCS/TC off I got 17.8. Prob 60/40 city/hiway. I shift around 3000 rpm; hiway cruise at 80; never redline; almost never above 6000 rpm.

I'm not sure we have enough data yet to say that the DSC/TC is making a difference or not, just a few anecdotal stories and theories. I'm gonna try it every other tank or so; my current tank I'm not doing it. Let's keep at it and see if we can really establish whether this makes a difference or not.

Yeah, I've had it off for at least 2 tanks now. I thought my mileage seemed better during that 1st tank, but realized that I had also changed the oil. Upon my next fillup, I did the calculations, and mpg was still between 17-18. So, not really an improvement. I've still been leaving it off, though (except when the kids are with me), just because it is so much fun.

Originally posted by B-Nez
I've still been leaving it off, though (except when the kids are with me), just because it is so much fun.

Good point, I forgot to mention. Leaving DSC/TC off brought back that satisfying squeal of tires that had been absent. When I picked up my son at school his friends out front were admiring the car (15-yr-olds). when I pulled a quick U-turn and the tires squealed a bit they were in nirvana with this car. It was way cool.

My world with my RX8 is squeling tires and slipping around sharp turns. It kinda brings the sportiness back into the car.

Also, I always drive conservitive in my car with my family.

I LOVE making U-turns, now. Much easier with DSC/TCS off. Also, now when powering around a tight corner, I get that little bit of wheelspin that I can control, rather than DSC cutting my throttle to almost 0 and making that thumping sound. :D

It is pretty fun with it off thru the turns

Yesterday, i filled the car with premium (93 octane) and was careful to fill it exactly. I then started the car, disabled the DSC nad the TCS, set the air on two and with windows up and sun roof closed headed for the highway. It was a 4.5 mile run to get to the highway and I drove the car very easily. Upon reaching the highway, I headed north and slowly brought the car up to 70 mph. I then set the cruise on and left it. Later on the run, the speed limit increased and I reset the cruise up to 75. The total run one way was 71.8 miles. I stopped at a new casino on the Oklahoma border and went in to get a bottle of water. While there, i decided to try my luck. I less than two minutes I was up $43.00 and grabbed the money and ran. On the return trip, I did the exact same thing with the cruise. i wne trihgt back to the gas station to the exact same pump to fill up as before. It took 6.082 gallons and I travled 143.3 miles. That meant i got slightly more than 21 mpg. The weather was at 77 degrees and there was no wind to speak of.
I don't know how I could have done it better and was trying to see the BEST mieage I could achieve when driving in a fashion that represnted my typical driving style.
My question is, how can someone else living in the same area, toting two passengers, driving more in the city get 28 mpg? I would sure like to know. If it is true, there has to be significant differences between one car and another.:confused:

Is 75mph and 70mph over 3750 RPM? Because that's when the 3 injectors start fireing.

I usually cruise at 110km/h which is below the 3750rpm.


I'm happy it is sooo fun today I was going 90mph around a tight corner (it felt like I was only going 60!)...

Originally posted by boowana
It took 6.082 gallons and I travled 143.3 miles. That meant i got slightly more than 21 mpg.

boowana,

How come you calcuated 21 mpg?

143.3 miles / 6.082 gallons = 23.56 mpg !

Originally posted by boowana
....My question is, how can someone else living in the same area, toting two passengers, driving more in the city get 28 mpg? I would sure like to know. If it is true, there has to be significant differences between one car and another.:confused:
Simply put: They're not...

you are not too far off. The 2001 MIllenia lost 2mpg running the AC. If you round which is what they do, you got 24 + 2 would be 26.

I couldn't find this anywhere set in stone...... our tanks hold 15.9 gallons as stated in manual..... correct?

Originally posted by PoLaK
I couldn't find this anywhere set in stone...... our tanks hold 15.9 gallons as stated in manual..... correct?

Correct.

I noticed something funny- though I am getting bad mileage 10 city and 16 -17 highway- there is not alot of black soot on my tailpipes- AFter 1200 miles just a bit on the bottom of the pipes.

ANy significance?

Originally posted by boowana
Yesterday, i filled the car with premium (93 octane) and was careful to fill it exactly. I then started the car, disabled the DSC nad the TCS, set the air on two and with windows up and sun roof closed headed for the highway. It was a 4.5 mile run to get to the highway and I drove the car very easily. Upon reaching the highway, I headed north and slowly brought the car up to 70 mph. I then set the cruise on and left it. Later on the run, the speed limit increased and I reset the cruise up to 75. The total run one way was 71.8 miles. I stopped at a new casino on the Oklahoma border and went in to get a bottle of water. While there, i decided to try my luck. I less than two minutes I was up $43.00 and grabbed the money and ran. On the return trip, I did the exact same thing with the cruise. i wne trihgt back to the gas station to the exact same pump to fill up as before. It took 6.082 gallons and I travled 143.3 miles. That meant i got slightly more than 21 mpg. The weather was at 77 degrees and there was no wind to speak of.
I don't know how I could have done it better and was trying to see the BEST mieage I could achieve when driving in a fashion that represnted my typical driving style.
My question is, how can someone else living in the same area, toting two passengers, driving more in the city get 28 mpg? I would sure like to know. If it is true, there has to be significant differences between one car and another.:confused:

Let me get this straight... A Texan went to Oklahoma?

Originally posted by 8_wannabe
Let me get this straight... A Texan went to Oklahoma? I guess Boo must be a Texas Democrat. :)

As Oct. 1 approaches, what is the consensus on the DSC full turnoff:

(1) -- boost HP?

(2) -- boost mileage?

Sounds like subjective yes on (1) and objective maybe on (2) (not enought data). Anyone else with data or conclusion?

Originally posted by eccles
I guess Boo must be a Texas Democrat. :)

no, just a Canadian (aka to Reps: 'liberal') ;)

simple BOO! your calculation of your mileage was off and so was the person's who said they got 28. you got 23.5 mpg!congrats:)

Hi

This is an interesting thread. I've ordered my rx-8 but it won;t be here for 2 months.

Has anyone ever played Gran Turismo. You can turn off both DSC and TCS. IN this simulation that's over 1 year old there is significantly more power with the DSC off. With TCS off as well, the car becomes more uncontrollable.

I know it's not the real thing, however the engineers at Sony have it spot on I imagine.

I'm not sure about the gas mileage for the 8 but i'm getting ready to sell my miata to buy one and while i owned the car i noticed that if my tires were low that i would lose almost 5mpg. So you might want to check your tire pressure it's hard to tell if its low, i was driving around with 10psi in one tire, (there was a nail in it) and it took a few days to figure out what was wrong. Also i'm not sure who's wrong but mazda rates the gas tank in a miata as a 12.1gl tank, yet i've put as much as 13.2 gls in the car. So if someone has put more than 16gls in their car.....

For the hp, the same thing happened in 2001? 2002? (i think) with the miata, they advertized it at 155hp but as soon as it hit our shores it was changed to 142hp the same thing seems to be going on with the rx-8 now. It could just be some emissions control. Also of note; some of the prototype engines had problems with the aux ports opening causing the manuals to run on only 4 ports rather than 6. But from all i've read it seems that in the 1500-3000 mi range that most of the cars start to see an increase in power. My theory is that the ECU is protecting the engine through its break-in period by not allowing it to have full power and once thats done it could be opening things up.

One last this, it's rumored that most of the magazines and testers ended up with the lower powered engine because of the faulty ports, so check around.

That's an easy one to cover:
1) I personally check my tires at very fill.
2) USA models have low air pressure sensors in each wheel.

Thanks for the great thread.
My GT has just came back from the dealer with a faulty solenoid vacummun valve on the intake tube.Not sure the proper name for it...it opens the secondary intake tube after 4500rpm.
I have always said my gt really lacked in the upper RPM ranges..this has been the cause of it.
When the new part comes from japan i to will test your theory.

Just started trying this on my new tank of gas.

I have the base model with sport package, no traction control of any kind and my mileage sucks. Still love the car and wouldn't trade it for the world.

Most of my MPG entries to date are very similar to these.

Date Trip Gallons MPG Odomoter
1/31/2004 167.3 12.296 13.6 1051
2/8/2004 75.9 6.005 12.63 1324
2/10/2004 139 9.838 14.1 1463

That's horrible. Just filled up last night with 10.938 gal of 87 octane at 195.6 miles. 17.88 mpg with DSC/TCS on the whole time. With 3400 miles on the 8, my mpg has been roughly the same since day one.

I'm taking mine in next week to see if they will reflash the ecu, or do something to help. I'll let ya'll know how it goes.

If you have the Sport Package, you have DSC/TC.

Only the base cars do not have it.

Sorry bout that, I have the base model. No foglamps or any extras.

No biggie.

While you're at it, how do you like the stock halogen headlights?

The SP is one I wanted, but really only for the HIDs.

Thanks,

Well definatley a big improvement over my 94 miata's head lights (barn doors). But if I could just pick one option that i didn't get it would be the xenon's....don't really care to have any of the other options. Had leather in the miata and decided I din't want it in my next sports car. Everything else is just weight to me. I'm use to driving carefully (granny-like) in the rain and this car handles so much better in foul weather (well at least it's heavier and less prone to hydroplaning) than the miata that I didn't feel I needed traction control. Fortunately no accidents or tickets in past 6 years, so that helped in my decision too. (And the base model was just too much bang for the ole buck...almost felt like stealing ;) )

A good friend of mine that owns an s2k was marveling that the headlights on his car look identical to mine. I'm enjoying them so far. :)

I guess I'll be the first to call 110% bullshit on this.

TCS/DSC/XYZ/ABC/DEFG.. bullshit.

If the computer isn't applying the breaks and/or chanign the F/A mixture (which as non tcs/dsc users have stated getting bad gas milate)..this is 110% placebo.

The computer isn't doing SH!T ... DSC/TCS to the A/F ratios..and thats about the only thing thats going to effect milage (unless the brakes are secretly being applied-- I think not).

..Bogus.. all of thsi.

thats my $.02,
Aaron
p.s. I got 13.03mpg last tank.. DSC/TSC on/off?? who cares..it doesn't matter.

Interesting. As many things as I've read on this forum (not to mention contributed) it's amazing that I've missed this thread until today. Have to start experimenting with this.

Yes I have missed this thread also and I'm going to try it, won't hurt to play.

I doubt it will do much for gas mileage, but at this point I'll try anything.

As this thread was resurrected from back in late September, has anyone been doing this test since then and what are the results? Let’s have some long-term updates.

I just started turning the DSC/TCS system off after learning how to do it this afternoon and reading another thread regarding potential benefits. I noticed a marked improvement in shifting and drivability from my initial impressions on a couple of short trips of 10-15 miles. I turned it back on in between the two trips just as a test and it seems that the improvement is really there with the system off.

I still don’t have enough data to determine the impact on gas mileage, but I’ll be keeping a close eye on it. I have now some 735 miles on the car, so it would seem that the car is well within the initial ECU controlled break-in period of running rich. I went 645 miles on the first three tanks with fill ups of 13.9, 15, and 14.5 gallons each, which puts the current mileage at just under 15 mpg with only short trip driving - no trips over 20-30 miles and predominantly much less. I would think that in actuality, it is slightly higher because I’m sure the dealer didn’t top off the tank completely as I do on every fill up. This also includes the 30 miles that were on it when I picked the car up on Jan 28 . . . I still shudder to think of what my baby went through on those first 25 miles (about 5 miles was my test drive)!

Originally posted by Omicron
Interesting. As many things as I've read on this forum (not to mention contributed) it's amazing that I've missed this thread until today. Have to start experimenting with this. Actually, you haven't missed anything its just another speculative thread that has not delivered, just let the rumor die, it's BS..

Since brothervoodoo says it's BS, I'm sure he has tried this and must know from the wealth of statistics in his BS reply/claim. :D :D

I've tracked every fill-up and now have close to 11k miles. I've had DSC fully off for a quite a few fill-ups and it has made no difference in mileage.

side note:
If you notice the thread author has not posted since September has had less then 30 posts total, of which most of his posts dwell on mileage issues. It seems this person was very eager to find a magic bullet to improve mileage, I don't think this is it.

The only time you will see a nice jump in MPG is when you are cruising the freeway.

What I (and some others as well) have found, is this: Don't let the Renesis idle and longer than neccessary - it makes a considerable difference in the MPG. This includes (unfortunately) stop lights, stop Signs and warming-up the car.

Originally posted by brothervoodoo
I've tracked every fill-up and now have close to 11k miles. I've had DSC fully off for a quite a few fill-ups and it has made no difference in mileage.

side note:
If you notice the thread author has not posted since September has had less then 30 posts total, of which most of his posts dwell on mileage issues. It seems this person was very eager to find a magic bullet to improve mileage, I don't think this is it.

The only time you will see a nice jump in MPG is when you are cruising the freeway.

I agree. I put this little theory to the test, and I got absolutely no improvement in gas mileage. Looks like my 8 is gonna be getting around 20=22mpg highway, no matter what speed I drive at, or whether I have traction control on or not. he was looking for magic bullet, and he's either dreaming, hallucinating, or in denial. One or other, because you will not improve fuel economy by turning off traction control.

I used my G-Timer today to test acceleration with DSC and TCS enabled/disabled. The car felt more lively with the system disabled, but I wanted to test it.

I measured 0-60 without revving the engine prior to launch and allowing no wheel spin at any time. The 0-60 times were slow as the engine really bogged off the line, but I was consistent in all four runs--two in each mode.

Enabled: 7.38
7.40

Disabled: 6.95
7.07


The car also seemed to coast better with the system disabled, so I tried another test. I have a big hill as approach my neighborhood and I usually coast down. I come over the crest about 30 and I usually hit a max of exactly 53 right before the hill levels out at the bottom. Same every day within a mile/hr. or two. With the system disabled the coasting speed was exactly 53--same as always.

It appears to me there is a measurable difference, though not in drag but in engine response. Four runs is not definitive, though there was consistency in the times within each mode. I will test again.

Just to keep the controversy alive.

all this horsepower and milage thing is giving me a headache. I love this car . I have 3400 miles on mine and the mpg is a big flat 11.9. What can I do? the dealer keep telling me that the mpg is something that have to live with. Some friend of mine told me about something called a tornado that he claim help his mpg in his Big ass truck suv. he said that i need one. What is a tornado have anybody used it before on their Rx8.





_______________________________
2004 Rx8 Titanium Grey, GT, Strakes, Exhaust Finishers, Spoiler, Spare,

I know what a tornado is. It's a little finned peice of metal that you place in your air intake. It's designed to help optimise the mixing of air and fuel by spinning the air as it enters your engine.

As to how it works on the RX-8, I don't know. I too am interested to know if it makes any difference or not. I'd imagine it wouldn't make any difference since all the quotes I've seen for impressive MPG and HP gains posted on their website (www.myauto.tv) are for relatively old cars (the newest is a 95) I'd imagine that the engineers of new cars would acount for the uses of this "tornado" effect and engineer it into the car. However if anyone has one of these gizmos, I'd like to know if it works too.

my t-i-m....How are you driving your car??

11 MPG?!

I just got mine, and my first tank of gas put me at 18.4 mpg, with 90% city driving. Remember, that was my first tank of gas. That means I shifted out of every gear around 4000 rpm or so, and didn't race. I gunned it a couple times for fun, but I didn't drive around like that regularly.

18.4, and you got 11.

Your dealer said to just "live with it"? I'd be on the phone with Mazda corporate right now if I were you. That's a HUGE differential and strongly suggests that there is something wrong with your car. I most certainly would not just "live with it".

Hell, that means your car's range is under 150 miles! How can that be acceptable in anyone's mind?!

Man, you got 18 in the city? Wow.

I think I'm probably only getting about 13-15 with mixed driving. :(

Worst I've ever gotten was 14.9 MPG, and that was with some serious racing around... I had to give a dozen or so people rides in my car at our last club mini-meet so they could all experience the CanZoomer Stage 1 + Borla + Rotary Extreme SRI firsthand. But on average, I get ~17MPG in the city and have not had the car on the highway yet.

As for the "Tornado" gadget - it is complete and utter BS. Don't waste your money! It's been discussed in detail in the tech and aftermarket performance forums, in case you want to go searching.

Basically there is no "magic bullet" for improving the '8s fuel economy, unless it's driving style. As an experiment this week, I am reeeeeally trying to keep my shift points below 3500 RPM, as the secondary injectors kick in at 3750 RPM. It'll be interesting to see how much of a difference this makes.

And finally, the DSC/TCS disable thing... dunno. If BV and other credible sources have tracked it and found no difference, then it's most likely just wishful thinking. I too will be playing with it, but not until next week after I finish my current experiment on improving the mileage. But I'm not expecting disabling the TCS to improve my mileage - I'm more interested in the potential performance improvements. :D

If 14.9 was my worst I wouldn't be trying to improve my mileage. 14.1 is my best and 12.3-13.1 is pretty normal no matter how I drive, or the octane I use. Omicron do you think the hotter spark plugs might help me? The more I read on the issue the more I'm not sure what to do...

yes I'm getting 11.9 -- 12.0 mpg I drive my car on the hiway and street. I shift gears @ 4000 to 4500 rpm for each gear. this mpg is not acceptable for me. I took my car to the dealer today and the shop supervisor. told me to run 5 fill ups and note the milage, gas amount, bring back the information. then they would look at my engine to determine if anything is wrong with my rx8.. I have been using 93 octane at every fill up. 150- 158 miles per fill up.

I think he has found a "magic bullet" for his car and his car alone. Everyone believes in factory flukes, why is not possible for his car to have DSC applying the brakes unnecessarily?

There is such a wide range in the reported MPG, it is hard to get an accurate average. For the most part, I think all this DSC, TCS, MPG, and BHP is in our heads.

The performance range in the four RX-8s I test drove were ridiculous. There was definitely a difference between them, but sometimes it is easier to buy and love it for the good and the bad than to worry about performance and MPG. Both of which affect each other greatly. So pick one, you apparantly can't have both.

I'll pick something in between.

That would be a great deal if you could gain perfromance by disabling DSC/TCS. It just does not make any sense though.

I tried it yesterday after I read the first note and did not feel any difference in high and medium accelaration runs(not measured, just seat of the pants).

I think I will chalk this up as the "placebo" effect. Cover your instrument panel so you don't see the DSC/TCS lights, have someone enable or disable for you without your knowledge and see if you can tell a difference.

If you are hammering your car (high, high-medium acceleration runs) disabling DSC/TCS will help. But with normal day to day driving there's no difference (unless you hammer your car all the time!). If you go into turns aggressively (and before going past the envelope) there's a noticeable difference between having DSC-TCS on and off. But getting back to mileage, turning off your traction control does not improve mileage in my experience.

This is a very interesting thread! I've had my RX-8 for 2k miles and have averaged 14-18 mpg depending on the city/hwy mix. I've always had the impression that the brakes are dragging just a little bit and I'm going to try the TCS/DSC diable to see if there is a difference. It seems reasonable that the DSC on some cars could cause brake drag. I'll do some testing and report in a few days.

Interestingly, my BMW with a V8 and auto trans. is quicker than than the RX and averages 21 mpg!

2nd revival of this thread...

Hoax or real... what was the final consensus?

Also, can anyone comment on CZ Stage 1 w/TCS/DSC vs. w/o?

TCS/DSC = no real change in mpg.

Lots of idling eats a lot of gas = poor mpg.

Driving it like you stole it = poor mpg.

Driving it reasonably (don't WOT/beep every shift, etc.) = good mpg.

I drive mine fairly reasonably, but do have some "fun" too, and typically get 19 mpg in suburban/semi-rural driving.

I forgot about this.

I'm gonna give it a try. I'll be filling up tomorrow (along with my K&N intake install). I'll see how it goes...

Originally posted by w2aew
I drive mine fairly reasonably, but do have some "fun" too, and typically get 19 mpg in suburban/semi-rural driving.
As do I (see my mileage log in the sig). Disappointing, but I've learned to live with it.

i havent noticed a big difference between TC and DSC off and not. freeway = 21-22 mph, city = 17-18 mpg. pussy foot regular driving = 19ish.

btw- the dsc is pretty damn nice. i race a powerful RWD car and the DSC in the 8 is very good, not too obtrusive.

james

holy shiznit! im going to try this. i get a consistant 13-15 mpg tank in... tank out.. and i have even driven like my mother through entire tanks. shifting between 3-4 every time. never taking it above 4.5. and i still cant break 15 mpg. i will do an entire tank. with tsc / dsc off completely and compare it to the mpg when it is on.

I have done nothing special to mine, left DSC/TSC on, horse around with it off sometimes. I now have 5500 miles on it and the more I drive it the better gas mileage I get. I think the engine just gets better mileage as it gets broken in. I averaged about 16 to 17 when I first purchased it and now I am more around 21/22. Mixed driving of course. in both cases.

interesting thread, I am contemplating on testing this out, but at the current rate of premiuim gasoline in california, it was 2.65 last night, Ill switch to my rx7 for awhile until the price per gallon stabilizes.

happy rotoring!

sounds good, im gunna try it :)

Originally posted by RodsterinFL
using regular gas made mine run better (smoother) the first tank of regular I DROPPED to 14 mpg. but it quickly improved. I know I cannot MAKE any of you switch to regular gas but I cannot emphasize enough the difference it made on my engine. THe thing acted like it was choking before on 91. Like it was bogged down all the time. Then with regular it was as if it became free rolling (emergency brake off!!!) I keep reading where people used regular and their engines would barely run or started knocking hard, etc. I have a difficult time with that with all having the same engine and all.

im having a hard time following this... ur saying that 87 octane gas is giving you better performance along with better mileage as opposed to 91 octane?

Better gas mileage when driving like a bat outta' hell? Yeah right! Read how fuel gauges work first:

http://auto.howstuffworks.com/fuel-gauge.htm

Originally posted by doc.marx8
interesting thread, I am contemplating on testing this out, but at the current rate of premiuim gasoline in california, it was 2.65 last night, Ill switch to my rx7 for awhile until the price per gallon stabilizes.

happy rotoring!

Your RX-7 gets better gas mileage than the RX-8? My TurboII gets about 15mpg in comparison to my 8's 21mpg..

I don't have traction control, and still can't get over 15 MPG in my hilly area.

-RUpes

I tried turning off DSC/TSC last night, and was pleased to find even more performance than before. Thanks for the tip!

DSC/TCS off can't boost hp. The car's hp is what it is. Spinning tires doesn't mean more hp, just that the electronics aren't applying the brakes in low traction conditions.
Also played around with it on and off, doesn't seem to be an appreciable difference in mpg. I leave it on these days - probably saved my butt a couple of times and I didn't even realize it....

DSC/TCS off can't boost hp. The car's hp is what it is.
There are a number of sources of replacement ECUs and control chips that boost engine performance. You can invalidate your warranty by swapping control chips and producing too much power. People spend good money to buy canzoomer's ECU mods. Obviously, "the car's hp is what it is" isn't correct.

The ECU is in control of everything, and it gets data from DSC/TCS sensors. There are any number of ways the systems could interact... even a bug in the firmware could be in play.

It would be nice if people with access to performance measurement equipment could do some testing. People here have documented improved performance by timing their cars; it's worth examining in more detail.

Nowadays, with drive-by-wire throttle systems, the DSC and TC systems DO reduce throttle and possibly also timing to reduce power going to the rear wheels. The RX-8 DSC and TC systems DO use throttle and timing control in addition to brakes.

Amen,

I got stuck in a snowstorm in Seattle about 1 week after buying my 8 last year (yes it actually snowed 6" here).

I got stuck going up a steep hill, not because I was spinning but because the TC system was cutting off throttle. Go stick some grease on a dyno and try it if you want to reproduce the effect of a snowpacked road :)

Anyway, it seems kind of odd though that at normal moving speed without any turning or rapid accelleration/braking that DSC or TC would have any effect on fuel mileage. But since my only real qualm with my 8 is that it doesnt even come close to living up to that sticker estimated MPG, I too will be trying this theory for the sake of argument.

Right now I get right around 245-255 miles to the tank with 70hwy/30city driving. I also just got the 'M' chip flash so we'll see if the 2 combined make any difference. :o

I found this video somewhere on the web... although it is in some Asian language that I do not understand, you can clearly see the benefit of keeping DSC switched on... performance and fuel efficiency is way less important than your own safety (and the safety of those driving around you). Although I would love to get more mileage out of my car I do not think disabling safety feature a viable option.... just my 2 cents... check the video out!

http://www.alexruffell.com/rx8/DSC_demo.wmv

our GS model here in Canada has no traction control at all and the car drives very nicely and is very predictable in any circomstances. I think the DSC thingy is great but it makes the driver feel he can do no wrong, hence the false sense of security.

This is all interesting. I have a 6 spd but no traction control or DSC. Has anyone tested a base 6 spd against a loaded one? I literally bought the 1st one off the lot like last july and it wasn't loaded. I had to have it. How much lighter is it compared to the loaded versions? I don't think you can find one now that isn't loaded down.

here in Canada you can... base GS model and loaded GT model !! Only 2 to chose from. You can add nav and roof on the GT, only roof on GS i think

My 8 has TC & DSC a feature that I like for overall safety. I've tried turning it off and really did not notice a difference in performance or mileage. However, the system works by both cutting the throttle and applying the brakes so it may be possible that a malfunctioning system could hurt performance by creating brake drag, a condition that would also hurt mileage! So switching off DSC probably cannot give the engine more power, but it would feel that way if it eliminated brake drag! Also if the DSC was preventing full throttle, a performanc reduction may occur, but this should not affect mileage.

Having said all that, I find that my 8 feels like is does not roll as freely as my other cars. If you coast to a stop without touching the brakes, it has a little lurch like the brakes were applied. It also seems to decelerate very quickly if put in neutral and allowed to coast. Turning off DSC has no effect on this condition and I wonder if I am getting brake drag or if it's drivline friction. Any one else have this impression? I'll try to do some experiments to see if I can verify the drag.

I wonder if I am getting brake drag or if it's drivline friction. Any one else have this impression? I'll try to do some experiments to see if I can verify the drag.

I took mine for a drive... I ended up finding out how many intersections are not really level! :) No problem here, but it's only got 540 miles on it.

Could there be build-up on your rotors, perhaps? The pads contact the rotors even if your foot is off the brake.

I did a test of the DSC off today. Noticed the pitch of the engine hum seemed to be a bit lower. Didn't have any chance to check the hp, got stuck behind a slow moving smelly dump truck :(

I'm getting a theory on what's up with HP vs. DSC, and I think it's how hard you hit the car. I do curvy roads, and with it off, I've been drifting two curves and on the edge of a few others. That couldn't happen at all with DSC on... so...

I think everyone is right. Those who hit hard feel the full performance capability when DSC is off, those who don't, don't. It may not be an increase in HP, but it could be HP available for the slightly insane, that they can't have with DSC on.


[7/5/04] Another thought occurred to me. I'm running the L-Flash. Is it possible that those who feel no change are running the M-Flash?

I try to keep an open mind about things, and I've tried to be fair about the concepts in this thread. I discounted the original claim of "50% increase in mileage" as that's too large to be real. After reading several users test times, I thought there might be something to the claim of increased performance.

I felt it when driving curvy roads on the threshold of traction, and others have reported better results in drag-race type testing. Both of these induce wheelspin, which could definitely result in improved overall performance with DSC/TCS turned off.

I wanted to isolate any real increase in performance (or horsepower, if you will). I came up with a test that removed wheelspin: rolling start in 2nd at 20, measure 25-50... rolling start in 3rd at 30, measure 35-60. Here are the results:

DSC/TCS: ON ... OFF
25-50 #1: 4.02 .. 4.01
25-50 #2: 3.42 .. 3.45

35-60 #1: 5.31 .. 5.31
35-60 #2: 5.28 .. 5.31

I put a Philips ToUCam in the car, capturing tach, speedo and view. These results have been determined using a video editor to choose the first and last frames based on the digital speedo. As you can see, there is no difference at all. If your tires aren't losing grip, running with DSC/TCS fully off does nothing to improve your car's performance. Increased performance only comes when you are inducing wheelspin and have the tires and pavement to take advantage of it.

This book is closed, for me.

I try to keep an open mind about things, and I've tried to be fair about the concepts in this thread. I discounted the original claim of "50% increase in mileage" as that's too large to be real. After reading several users test times, I thought there might be something to the claim of increased performance.

I felt it when driving curvy roads on the threshold of traction, and others have reported better results in drag-race type testing. Both of these induce wheelspin, which could definitely result in improved overall performance with DSC/TCS turned off.

I wanted to isolate any real increase in performance (or horsepower, if you will). I came up with a test that removed wheelspin: rolling start in 2nd at 20, measure 25-50... rolling start in 3rd at 30, measure 35-60. Here are the results:

DSC/TCS: ON ... OFF
25-50 #1: 4.02 .. 4.01
25-50 #2: 3.42 .. 3.45

35-60 #1: 5.31 .. 5.31
35-60 #2: 5.28 .. 5.31

I put a Philips ToUCam in the car, capturing tach, speedo and view. These results have been determined using a video editor to choose the first and last frames based on the digital speedo. As you can see, there is no difference at all. If your tires aren't losing grip, running with DSC/TCS fully off does nothing to improve your car's performance. Increased performance only comes when you are inducing wheelspin and have the tires and pavement to take advantage of it.

This book is closed, for me.

Interesting. Did your tests involve any gear changes? I read in another thread that with the DSC/TCS enabled it seems like it takes a fraction of a second longer for power to kick in just after a gear change. (I have to admit that although I keep thinking about trying this myself, I have never even tried turning the DSC/TCS off! What a loser... :p )

Thanks for the information.

Interesting. Did your tests involve any gear changes? I read in another thread that with the DSC/TCS enabled it seems like it takes a fraction of a second longer for power to kick in just after a gear change. (I have to admit that although I keep thinking about trying this myself, I have never even tried turning the DSC/TCS off! What a loser... :p )

Thanks for the information.
No, they didn't. I intentionally tested without shifting to eliminate subtle changes between shifts in different tests, as well as possible wheelspin in the 1/2 shift. I know that when I want to play, and have visibility and room for things to go wrong, I can turn the systems off.

I almost hit a deer about an hour ago doing some "athletic" driving. It happened just past the apex of a curve as I was accelerating, and I instinctively nailed the brakes. The DSC/TCS systems did their job - I stayed in my lane under hard breaking that threw the weight to the outside front tire in a fraction of a second. Those late-night tests may have saved the deer and my brand new car, so I think I'll have it on 99% of the time and get CZ Stage 1 and high-flow catback exhaust to get some extra kick.

I have read the thread from start to finish. In the begining this dude solved the problem of performance/MPG. Then in the middle of the thread you only get performance, and then in the end of the thread you get NOTHING (BOO), dang I feel robbed. I was hopping to get performance at least. Well I am still going to try it and see how the placebo effect feels like. I have gotten 300 to the tank (89-92 octain) with the L flash and dsc/tcs on, currently have 12000 miles on my 8. I have just upgraded to the M flash, and to make sure I have the m Flash, I did the tap the break 20 times with car off and watched the temp gauge go up and down. I still have to test the car with the M flash with the dsc/tcs on. Well looks like I have another test to due with it off, but thats going to be at least 5 fillups down the road. :D

I Have the 2004 RX-8 with the Grand Touring Package. I kno i havet he DSC but do i have the TCS?

Shouldnt the grand touring package come with that? Ive got those (I have the grand touring package)...

u sure? The button is below the steeringwheel, towards the door...

yup, you have. "Read the manual" (that will answer a lot of questions that come up). Hold the DSC button down for 8 seconds and if you get the "warning there are snakes following your car" (LOL...thats from the "Facts of Life").It will be in the middle of your tackometer.

I think I got my "best" tank recently.

I filled up on Sunday. Drove 295 miles since, and refilled 12.9 gallons. That averages out to about 22.9mpg. 14,200mi on odometer.

Avg ambient temp 88ºF, A/C off, DSC/TCS on, windows down, sunroof open, ~200 freeway miles, ~100 street miles.

One thing that might have helped me was that I never exceeded 75mph on the highways, and purposely accelerated slowly.

My theory:
Having a K&N intake helps gauge how much throttle should be given to attain the best mpg. If you step on the gas pedal far enough to make the intake rumble while accelerating, a significantly greater amount of air gets sucked in. At that point the ecu is probably increasing the duty cycle of the injectors, which results in more gas being used through a shorter distance travelled. So, if you can drive in such a way as to prevent the intake from making that deep growl, your chances of getting better mpg are increased.

Sorry for rambling. It's late and I have no air conditioning. Plus its 90ºF around here and my fan is blowing hot air at me. :(

Here's my first comparison... I'm not sure which of the 3 (or possibly all 3 combined) caused improvements but my MPG is hugely improved-

Before:

Original flash ('L')
93 Octane religiously
Never turned DSC or TC off

Full tank ~ 240-250 miles per tank with about 70% Highway driving

After

'M' Flash
89 Octane
DSC and TC off the entire tank

Full tank = 297 miles w/gas gauge buried below E ... again 70% Highway driving

I'm going to do the same thing on this tank without DSC/TC off to see if there is any decrease. Either way, it's kind of relieving to hit the 1/4 tank mark with 250 miles on the trip meter instead of the low fuel light :D

Has anyone considered the gears you use most often? I do not thing DSC can really reduce your mileage since it only activates when your wheels are slipping.

Instead... I have found that for normal city use I tend to stay in the low gears (up to 4th) and rarely get up to 5th and 6th since the car has poor power at low revs... and high revs in 5th or 6th means you want to go to jail for speeding... keeping the car in its power sweetspot will make the drive more enjoyable but the gas performance will go down the sink...

just my 2 cents...

I found out just this weekend that changing gears at 3000 rpms and driving at 60 on the freeway you can get 300 miles and still have a quarter tank, but it was really boring doing that ( I sacraficed my driving fun) and I got cut off once, so I slapped it into 3rd and cherpt out on the suv driver. Basically even with one or two high reving beeps, you can still get 300 plus to the tank. To get good MPG you have to sacrafice the High Rev experiences.

"One thing that might have helped me was that I never exceeded 75mph on the highways, and purposely accelerated slowly. "


I have a problem with the claim about accellerating slowly. I think it was Car and Driver that did an experiment with a car on two different tanks (or even more...I can't remember). Basically what they found was that it uses less fuel to accellerate quickly. Their rationale is that you achieve your cruising speed (which doesn't use nearly as much fuel as accelleration) more quickly and therefore spend less fuel per amount of time. They even had some cool graphs and stuff.
I haven't tried this out, and I'm just saying what I read, but it seems to make sense.

"One thing that might have helped me was that I never exceeded 75mph on the highways, and purposely accelerated slowly. "


I have a problem with the claim about accellerating slowly. I think it was Car and Driver that did an experiment with a car on two different tanks (or even more...I can't remember). Basically what they found was that it uses less fuel to accellerate quickly. Their rationale is that you achieve your cruising speed (which doesn't use nearly as much fuel as accelleration) more quickly and therefore spend less fuel per amount of time. They even had some cool graphs and stuff.
I haven't tried this out, and I'm just saying what I read, but it seems to make sense.
Ture but when you go 100% throttle you Air to Fuel mixture is richer to prevent pinging so your using more fuel as well.

ok here are some numbrs

with L flash
91 octain
290 miles
filled up 14.567 gallons
regular driving and the
Beeping revs

With L Flash
89 octain
300 miles
Filled up 14.885 Gallons
kept it mostly 70-65

Upgraded to M Flash
87 octain
290 miles
filled up 14.670
70-65 mostly

M Flash
91 octain
283 mile
filled up 13.600 Gallons
had some fun and
was late for work
beeped reved a
couple times

M Flash
91 octain
338.4 miles
filled up 14.481 Gallons
changed gears at 3000 rpm
cruising with a/c on at 60-62 MPH
DSC/TCS off, traveled 338.4 miles in
one weekend 75 % freeway 25 % city

I am currently Driving with DSC/TCS on with 91 octain a/c on and keeping it at 60-62 and shifting at 3000 rpms, let yall know the outcome on the next fill up.

Ry

wow

wow I got to try this DSC thing....

Ok, so far I am at 320 miles with the M Flash with DSC/TCS turned on, shifting at 3000rpm, driving at 60-62 (its hard doing that) and I have the gas warning light on. Gas warning light came on at 320. My conclusion is that DSC/TCS turned off has no Effect on your MPG, but it does have an effect on performance.




I used my G-Timer today to test acceleration with DSC and TCS enabled/disabled. The car felt more lively with the system disabled, but I wanted to test it.

I measured 0-60 without revving the engine prior to launch and allowing no wheel spin at any time. The 0-60 times were slow as the engine really bogged off the line, but I was consistent in all four runs--two in each mode.

Enabled: 7.38
7.40

Disabled: 6.95
7.07


The car also seemed to coast better with the system disabled, so I tried another test. I have a big hill as approach my neighborhood and I usually coast down. I come over the crest about 30 and I usually hit a max of exactly 53 right before the hill levels out at the bottom. Same every day within a mile/hr. or two. With the system disabled the coasting speed was exactly 53--same as always.

It appears to me there is a measurable difference, though not in drag but in engine response. Four runs is not definitive, though there was consistency in the times within each mode. I will test again.

Just to keep the controversy alive.


Thread is now DEAD, now I can have Fun Rev Beeping my 8 again

There is no way to get 320 miles before your fuel light comes on. My experience has shown that light comes on at around 13 gallons used, or 2.8 left. This would mean you averaged 24 MPG on the first 13 gallons, and that is IMPOSSIBLE unless you set the cruise at 70 in 6th gear and drive 320 miles in one direction without slowing down or stopping.

Normal driving will include the startup time in the garage each day, stoplights, acceleration, etc. This will yield somewhere around 15 MPG. Once you average that in, you will be WAY under 24 MPG.

My fuel light comes on around 240 miles, and I think most other people's do as well.

B



S

You know, after reading a lot of people's data based fuel economy findings the main conclusion people are coming up with is :

1. When you drive a lower revs, you get better gas milage.

2. When you drive slower (in 6th gear), you get better gas milage.

3. Higher flow through the engine uses more gas through the engine.

These should be elementary principles of engines, whether piston, rotary, or otherwise. (don't flame me, I'm just trying to make a point... read on)

Since fuel vs rpm vs speed curves aren't linear, is there any information out there that details ml/min of fuel use at different bands in the engine? As the 3 injectors come on line in sequence, there is greater ml/min flow.

If we can get fuel usage curves at different engine speeds (while the car is moving to take into account drag) we should be able to calculate the optimum rpm to run the engine speed at any given car speed.

Anyone (Mazda Engineers, this a plug for you) out there have this information? We can put an end to the arguments with real data.

warning light on
and its at 324.3

so no

B

S

I'm not trying to be argumentative here, but EPA testing shows 18/24 mpg, which means a normal "per-tank" average should be around 20 mpg. You can't get 25 mpg on the whole tank. Every second you sit idling, you are getting 0 mpg. Every time you accelerate, you are getting 5-8 mpg. Average that in, and the "per-tank" average takes a huge nosedive.

I drive 52 miles one-way every morning and every night, to and from work. 90 % of the drive is on the FL turnpike, cruise set at 70. 19-20 mpg every tank since I bought the car.

No offense, but I could skip resetting the odometer when I filled up too, then my car would show 400 when the light came on..... :rolleyes:

I routinely get 285 miles on the odo before the gas light comes on, and average 21-22 mpg.

This is with spirited driving, taking it to redline at almost every time the ignition is turned on.

Could probably get the EPA mileage, but I didn't buy this car to drive it like a grandma.

I routinely get 285 miles on the odo before the gas light comes on, and average 21-22 mpg.......

That's nice.

What do you guestimate your average driving highway/city percentages to be and what type of fuel do you use? I average 20 mpg 50/50 highway/city using Shell 87 octane. I don't drive like grandma nor do I drive like I stole it, but I'm mostly in the left lane.

rx8cited

warning light on
and its at 324.3

so no

B

S

I have similar picture 187 at the halfway mark but i figured no one would believe me anyway.

I'm not trying to be argumentative here, but EPA testing shows 18/24 mpg, which means a normal "per-tank" average should be around 20 mpg. You can't get 25 mpg on the whole tank. Every second you sit idling, you are getting 0 mpg. Every time you accelerate, you are getting 5-8 mpg. Average that in, and the "per-tank" average takes a huge nosedive.

I drive 52 miles one-way every morning and every night, to and from work. 90 % of the drive is on the FL turnpike, cruise set at 70. 19-20 mpg every tank since I bought the car.

No offense, but I could skip resetting the odometer when I filled up too, then my car would show 400 when the light came on..... :rolleyes:
You will get better mileage driving at either 63 or 83 (and 96 if you’re willing) in 6th gear, if you plot your air to fuel ratios you'll see that these are the leanest points in 6th gear. (M flash)

There is a point 70-78mph where the AFR gets very rich I would stay out of that range.

Btw these numbers could be slightly off i haven't dynoed or plotted my A/F ratio in 6th gear only in 4th and 5th and there are slight differences in the M flash map per gears 4 through 6.

And you all wonder why i got a speeding ticket.

Here's my mpg since ~2300 miles. I've got 10300 on it now. My average is 19.544 mpg over the last 30 fillups (all 87 octane gas). There are 6 long distance trips (22.4 mpg average) in there and 2 autocross races (where I got 17.3 mpg). From the graph, I put in upper and lower control limits 2 standard deviations away from my average. There is only one point out of this 2 SD control limit and that's one which has been high due to a long distance trip. (I think statistically +/-2.66 * the standard deviation is how to calculate upper and lower control limits.)

By the way, I have a mix of DCS on and off. I've turned it off when I remember, but sometimes, I didn't bother.

For zooming around town and having fun, 19.544 mpg is alright with me. I give my 8 plenty of excercise. Once they start getting out of control, I'll start to worry.

Anyone have those air/fuel ratio curves in 6th gear???

I'm not trying to be argumentative here, but EPA testing shows 18/24 mpg, which means a normal "per-tank" average should be around 20 mpg. You can't get 25 mpg on the whole tank. Every second you sit idling, you are getting 0 mpg. Every time you accelerate, you are getting 5-8 mpg. Average that in, and the "per-tank" average takes a huge nosedive.

I drive 52 miles one-way every morning and every night, to and from work. 90 % of the drive is on the FL turnpike, cruise set at 70. 19-20 mpg every tank since I bought the car.

No offense, but I could skip resetting the odometer when I filled up too, then my car would show 400 when the light came on..... :rolleyes:


Well Thats you, not me.

Maybe that Florida Humidity is weighing you down :rolleyes:

If you mash the pedal, your gas consumption will suck. I consistently get 11.5L/100km (20.5mpg) around town, no freeway driving. Extended trips, it improves to 24mpg. DSC is on all the time. I've had the car nearly a year (next week is the anniversary), and its got around 14,000 miles on the clock.

I guess "good mileage" is subjective. Sunday I took the 8 out for some laps at Buttonwillow Raceway. The accelerator was pretty much on the floor whenever I wasn't braking or driving in the pits: 114.1 miles, 14.2 gallons = 8.04 mpg.

The mileage more than doubled on the trip back. Average speed about 90, DSC/TCS on, using gears freely, with the A/C full on in the 100+ degree heat: 278.8 miles, 14.4 gallons = 19.36 mpg.

Both of these figures seem reasonable to me, considering what the car was doing. Both were using Shell 89 octane unleaded. At the track, it saw 104-108 mph at the end of the longest acceleration area, and averaged 71-73 mph over the whole 3 mile circuit with many tight curves.

Turning off DSC/TCS has a noticeable effect on the track. The car is much more responsive in situations where one or more tires is sliding or spinning. There's one particular curve that was best taken by turning in hard and giving it full throttle just before the apex, causing a little back-end slide and powerful acceleration. With DSC/TCS on, the car would cut back its power and tweak the brakes in that situation. This showed itself in the max speed after this curve and before the next, about 78-79 with DSC/TCS on and 84-85 with it off.

I really don't think the engine develops more HP with the systems off, but I know without a doubt that the systems rob usable HP and tap the brakes in situations that are otherwise quite controllable - and best executed with power and a bit of wheelspin. The next test will be turning off only the DSC system, so the car can drift a bit but I won't get wheelspin on just one side.

I personally don't benefit from turning DSC/TCS off for street use. I don't start hard, and I don't often corner hard enough to bring them into play... the car is so fast that there are few places it's safe to corner that hard. I'd rather have the peace of mind of knowing they will help me through the unexpected maneuvers - like avoiding a deer suddenly bounding across the road.

RandyP,
Nice writeup! :)
rx8cited

Thanks, rx8cited...

Maybe it would be fun for people to see what it's like in an RX-8 on the track. I film my driving using a webcam, with the laptop buckled tightly into the right seat.

- Lap 1 - 15Mb (http://www.eldoradosoft.com/temp/Buttonwillow1-Lap1.wmv)
- Lap 2 - 15Mb (http://www.eldoradosoft.com/temp/Buttonwillow1-Lap2.wmv)
- All laps - 64Mb !!! (http://www.eldoradosoft.com/temp/Buttonwillow1-All.wmv)

There's no sound - the files would have been more huge, and with the windows open it was not much more than wind noise, anyhow. Lap1 and Lap2 are in All laps. In the last lap of "All laps", the engine cut out briefly on the long, high-speed stretch. That's when I saw my yellow low-fuel light on, and was pretty sure I only experienced fuel starvation. But this blinking engine-shaped idiot light came on, so I backed off the rest of the last lap before taking it into the pit. It all came out OK - the engine light went off when it decided it was nothing major, and I filled up my 8.04 mpg tank.

The curve that needs the power is the first right after exiting the pits, which is also the first right after the start/finish line. It starts a bit tight, goes uphill, then gets REALLY tight. That's when the RX-8 does best with full power and a little slide.

The car really held its own against some fast cars. However, you'll see a Z06 gobble up the RX-8 on the straightaway... 400HP vs. 238HP is no contest. An unidentified BMW also pulled away pretty strongly. What I need is a third rotor! :)

Nice Post RandyP,

+++Karma Points

RacingBeat has a 3 rotor engine for sale. It runs methanol and get 1000 HP, but it costs $50,000. I was at RacingBeat getting my Cat Back exaust. They also said they are getting closer to finishing their bench for the reprograming the stock ECU, they said they had to fly a guy out here from Japan to figure out the coding. Once that was done, they tweaked it abit and are getting 10-15 hp increase, just need to finalize everything and in will be ready. The plan is you bring your stock ECU RacingBeat Flashes it then tests it on the Bench Engine and you get it back the next day. How does that sound RandyP???????
Also they are developing a closed box intake system that will be quieter then K&n's intake, but it is like 2 hp less then K&N's. It also looks like the stock intake, so no worries of Warranty Violations with just eye balling it. :D

DUDE!!!!!!!!!!
RUDENAEUR, you are amazing!!!! i was always worried about the mileage of the car and how it boasts a 24 mpg and i get about 17 especially with the high priices of gasoline here in LA. thank you so much for the tip and i never even knew about the TCS disengage . THANK YOU again

RacingBeat has a 3 rotor engine for sale. It runs methanol and get 1000 HP, but it costs $50,000. Uh... I'd probably go for the Z06. :o

I was at RacingBeat getting my Cat Back exaust. I hope you like it... it's the system I have in mind. There's a thread about it -here- (http://www.rx8club.com/showthread.php?t=13923) where you can tell people what you think of it.

They also said they are getting closer to finishing their bench for the reprograming the stock ECU, they said they had to fly a guy out here from Japan to figure out the coding. Once that was done, they tweaked it abit and are getting 10-15 hp increase, just need to finalize everything and in will be ready. The plan is you bring your stock ECU RacingBeat Flashes it then tests it on the Bench Engine and you get it back the next day. How does that sound RandyP??????? It sounds like competition in aftermarket ECUs, and that's a good thing. After looking around this forum for a while, I'm getting more and more impressed at how well Mazda tuned this little 1.3L powerplant and its components. Of all the mods made by all the owners, ECU mods bring the most HP. Here I'm leaning towards Canzoomer Stage 1. I like to tinker and optimize things for my driving style and environment. CZ1 gives me detailed control over the ECU map. I also want to update the Mazda ECU flashes myself. Finally, CZ1 can be totally removed whenever I want the car in totally stock condition.

I'll probably look at the tires and suspension after the ECU. I'm interested in getting around the track quickly, and I think I get more bang for the buck in sway bars and sticky tires than other engine mods.

I've been ignoring the MPG claims, but for some reason I wanted to look into them myself last night. There's a question about Mazda's 24mpg figure, and whether DSC/TCS affects mpg.

I decided on an mpg test I thought would be reasonable for Mazda to conduct to get its freeway rating: 65mph, cruise control, clear night, still air, temps 60-63. Test is approx. 100 mile loop in very flat terrain, half in each direction to make up for any air movement and hills. Same gas - Shell 89 octane, same station, same pump, less than 30 seconds from the freeway. I shifted by the book: 14, 22, 29, 36, 46 mph (very boring). These speeds work out to 3000 RPM in each gear.

- With DSC/TCS on, 104.7 mi, 4.41 gal = 23.74 mpg
- With DSC/TCS off, 86.5 mi, 3.63 gal = 23.82 mpg

The test with DSC/TCS off was second. I turned around at a different place because it was getting late, so it's a bit shorter. The temperature was 1.0-1.5 degrees cooler, which would raise the mpg slightly. And while I tried to fill the tank exactly the same, I'm sure it was off by some amount... so to me these numbers are "the same". DSC/TCS should be left on for all normal driving because of its safety factor, but if you're driving hard in a controlled environment, turning the systems off lets you use all the power the engine can deliver.

As far as Mazda's claim of 24 mpg goes, I got very nearly that value. If I ran the test at 100kph/62.5mph I bet it would hit 24 exactly. I think it's amazing the car can go from 8.0 mpg at the track to triple that value for casual 65 mph cruising... or 19.4 mpg at 90 mph, A/C on at 100 degrees.

I guess if you're getting 17 mpg, you're just having fun with your car. :D I certainly didn't buy an RX-8 to drive around shifting at 3000 RPM...

[QUOTE=RandyP] I like to tinker and optimize things for my driving style and environment. CZ1 gives me detailed control over the ECU map. I also want to update the Mazda ECU flashes myself. Finally, CZ1 can be totally removed whenever I want the car in totally stock condition.

How much is the CZ1? Is it like 600$ and can anyone(laymen) change the mapping or could I get some advice from you on how to make the proper adjustments. Is it user Friendly to the point that I wont blow an apex seal. This is my first time having a really computerized car to trick out. My 1979 rx7 sooo much easyer to work on. That CZ1 seems to be a good choice since it is hidden in the spot where the stock ecu goes. For warranty issues. If I go with the CZ1 at least I can swap back my stock ecu easaly for when mazda snoops around the car, during inspections/oilchanges.

How much is the CZ1? Is it like 600$ and can anyone(laymen) change the mapping or could I get some advice from you on how to make the proper adjustments. Is it user Friendly to the point that I wont blow an apex seal. This is my first time having a really computerized car to trick out. My 1979 rx7 sooo much easyer to work on. That CZ1 seems to be a good choice since it is hidden in the spot where the stock ecu goes. For warranty issues. If I go with the CZ1 at least I can swap back my stock ecu easaly for when mazda snoops around the car, during inspections/oilchanges.That's the right unit. There is a data cable and programming software for the CZ. You'll need those if you want to tune it (or have to). It's very important to me that the unit be fully removable; I'm wondering what will happen if RacingBeat flashes an ECU - then a Mazda dealer checks its software rev and maybe a checksum and finds out you have a little surprise in the EEPROM.

I'm no expert with CZ1, to be sure. I've read enough to know a lot of people bought it and liked it, and a few people flamed it. The flamings come from people who don't want to tweak, but something like this *is* for tweaking. You'll need to read the dozen or more threads on the CZ's to get comfy, as I've been doing. When you feel you know what it is you're buying and know the principles of its use, you should be self-sufficient (or find answers in CZ threads in this forum, or from Canzoomer). I think every question you'll come up with has been answered here, somewhere.

Take note of intake systems as you look around, and the many concerns that have been posted. I feel the safe route is CZ1 + RB Cat-Back, and nothing more for the engine. Use your own judgement, but from what I've read... intakes give little gain and have potential problems, flywheels change the car's driving characteristics and make over-revving very easy, and underdrive pulleys have been noted to cause severe damage. Call it frustrating - or call it excellent, optimized factory design - your choice. :)

EDIT: I just read about the Group Buy from CZ, and it isn't going well. Caveat emptor! I'll wait for a couple months and see what's left after the dust settles.


As for this thread...

side note: If you notice the thread author has not posted since September has had less then 30 posts total, of which most of his posts dwell on mileage issues. It seems this person was very eager to find a magic bullet to improve mileage, I don't think this is it. ... it seems we have been victims of a practical joke... or wishing thinking.

I have found that my average city/highway gas mileage has increased by 50%!! Before, it was averaging 15 to 16 mpg. NOW, it's at 24! Has anyone, anywhere hit 24 mpg average city/highway? I nursed my RX-8 last night with nothing but pure cruise-control highway driving and it just about got to 24. The claim of 24 avg city/highway should have triggered my BS-sensors a long time ago.

I will try to get this car to a dyno sometime next week. I am extremely interested to see what kind of power variance (if any, a tip of the hat to skeptics) the car is putting out with the system on and off. ... and that was the last post of the thread's author. It was made last September.

So... this is my last post on this topic. I've tested the heck out of this proposal, and I've come away with respect for the DSC/TCS system and no indication at all that it affects mileage. Performance is affected, but that's to be expected when DSC is trying to PREVENT you from getting sideways. It has to react to first indicators of trouble situations quickly - it can't recover you from a spin you've already entered. So, it's reasonable that we note improved performance when we're driving hard, but it's unlikely the DSC/TCS systems are causing the ECU to produce too little HP under normal driving conditions.

Have fun with your 8. It's a "pay to play" world, and winding it up to 7K every shift costs a bit of money. So does riding the X at Magic Mountain. If you don't believe it can get 24mpg on the highway, do the test I did last night and see for yourself. If you think you can get 24mpg avg city/hwy like the author did... maybe you're smoking something other than your tires? ;)

.......
Has anyone, anywhere hit 24 mpg average city/highway? I nursed my RX-8 last night with nothing but pure cruise-control highway driving and it just about got to 24. The claim of 24 avg city/highway should have triggered my BS-sensors a long time ago.

Rotary Nut (automatic transmission) posted a few weeks ago getting around 26 mpg on a road trip. I'll try and find the link. Here it is: Its about time... 26 mpg Woot! (http://www.rx8club.com/showthread.php?t=32947)

rx8cited

I hope you get better MPG with 'ur automatic since the manual has 41 HP more with 2 extra intake ports.I checked out the thread and chose this as a good quote... then saw who posted it.

I know what I did last night, and it was the bare minimum power necessary to take the two round trips. My A/C was off, my speed 65 on cruise control, windows closed - everything set up for best mileage. (Note, the car has 2700 miles on it and may not be running as well as it will)

Well yes I use 87 octane Exxon regular, used the cruise at 10 mph over the limit the whole way and yes I have an automatic. Yes the AC was on the entire trip, upper vents were used only, and no, the recirculate was not on so it was sucking in fresh air from outside, except of course when I was traveling up the BQE on my way through the city.So... I had no A/C, 65mph, 6th gear MT and got almost 24 mpg... RN has A/C, 75-80, AT and got 26?

Someone in the thread asked what he gets on the return trip. That's an important question. I've driven in winds that add or subtract 4-5 mpg, and without a round-trip it's possible he had tailing winds the whole way. I also used the same pump each test, as different pumps cut off at different points due to different vapor capturing features or different pressures/periods in the pressure pulses used to determine fullness of the tank.

I have to think that Mazda would advertise 26 or 27 mpg for the car if it obtained it reliably. I'd need to see a more controlled test to be convinced that the car can repeatedly deliver that kind of mileage. I wouldn't give up my 6-speed for it, though! :)

Rotary Nut (automatic transmission) posted a few weeks ago getting around 26 mpg on a road trip. I'll try and find the link. Here it is: Its about time... 26 mpg Woot! (http://www.rx8club.com/showthread.php?t=32947)

rx8citedI had a thought. If Rotary Nut's car reliably gets 26 mpg at 10 over with the A/C on, he should be able to run the round-trip test as I outlined and get even better mileage than 26. Right?

I think he's proud his car *got* 26 mpg, and I'd be impressed if mine did under those circumstances, also. I don't think he's telling us the car gets 26 mpg on the highway routinely.

And - back to the topic of this thread - Rotary Nut didn't claim he saw it in mixed driving, or that it was a 50% increase in mpg.

Noting will happen with Racing Beats Ecu, the dealer will reflash it and erase all previous programming on it, and there will be no error.

You then would have to send you unit back to RB to have the programming put back on it.

I have to think that Mazda would advertise 26 or 27 mpg for the car if it obtained it reliably. I'd need to see a more controlled test to be convinced that the car can repeatedly deliver that kind of mileage. I wouldn't give up my 6-speed for it, though! :)

they CAN NOT advertise any mileage other than what the car tests at during the EPA testing. period. whether in the real world it gets lesser average or can reach a higher maximum under strict conditions. they are just not allowed by law. also someone said a page or 2 ago that 18 to 24 means an average of 20. not entirely accurate. the 18 is an average number for city and the 24 is an average number for highway. rotary nut is not the only person on this board to get above 24. i have seen several one way trips that have been over 24 including numbers in the 25 -26 range plus elara managed a 27mpg on one trip. they run the 2 tests 2 different ways. so you really can't average those to numbers. look at the window sticker and below those avg numbers you will see the range for each figure. will most of us ever see those higher numbers in the real world? no because you hardly ever have ideal weather and road conditons.

as far as your round trip being "more accurate" maybe so. but that is not how the highway epa test is done so i dont see what that proves, positvely or negatively, really.

Very interesting, i'm actually going to get up right now and go outside and give it a try. I will let you know how the mileage is over the next week.

[QUOTE=PoLaK]You will get better mileage driving at either 63 or 83 (and 96 if you’re willing) in 6th gear, if you plot your air to fuel ratios you'll see that these are the leanest points in 6th gear. (M flash)

So, air/fuel ratio is the only factor in gas mileage? Afraid not; air resistance is a major factor at these speeds, and it goes up at speed/squared.

Mitch

[rabid troll]
woohoo with dsc off it has so much more power! i can peel out and do continuous donuts now! when dsc was on my 8 couldn't do any of that! woohoo!
[/rabid troll]

[insomnia] so far my best 13 gallons has gotten me 290 miles, 75% highway, 25% street, with dsc on. turning dsc off has never made a difference.

So, air/fuel ratio is the only factor in gas mileage? Afraid not; air resistance is a major factor at these speeds, and it goes up at speed/squared.
Mitch Course not but I found it interesting that doing 95-99 yielded me a better MPG coming back from my dyno day then doing 75-80 going to my dyno. And the AFRs concurred.

Course not but I found it interesting that doing 95-99 yielded me a better MPG coming back from my dyno day then doing 75-80 going to my dyno. And the AFRs concurred.

One thing that was the dyno didn't capture was AIR RESISTANCE. That is going to put more resistance you the car travel than anything else at that speed. There is a lot more resistance put on a car at 95-99 mph than at 75-85. I doubt there is more gas milage at 100 vs 85. That would be difficult to swallow.

I went through some articles from Mazda about the DCS and TCS, appearently the traction control system controls the torque, if the tires loses traction, the torque is lowered (short version). It says this in the manual that comes with the car as well. So, if the tires slip at all, the torque will drop, producing less power.

I tested it out and so far have noticed some improvement in fuel economy (not much but enough to make it worth while).

Which is more important, a little more gas milage or the life of you or your loved ones riding with you. That is the question we must all ask ourselves. :eek:

I have to say I'm rather perplexed by all your obsessions with mpg.

Why did you all by such a performance car if you are just concerned with mpg?

I own an Elise and I've got to say I'm not fussed at being so much below advertised mpg rates as I just love reving the nuts off her and enjoying that fantastic acceleration braking and conering power.

So peeps for goodness sake like that last chap implied... go out enjoy your cars and be a prper petrol head.At least you US guys don't have to pay close to 45p a litre like we do in the UK.

Have fun

Love

ASHUS BUY AN ELISE!!!!!!!

At least you US guys don't have to pay close to 45p a litre like we do in the UK.


You paying 45p a litre, where?

I have to say I'm rather perplexed by all your obsessions with mpg.

Why did you all by such a performance car if you are just concerned with mpg?...........

Why the bloody hell are you so bothered by our "obessions" with mpg?

Just because we're concerned with understanding and improving our mpg does not imply that we're not enjoying our cars.

Not everyone in the world likes your favorite ice cream buddy, so do you think you can respect that, eh?

rx8cited

Yeah, I don't understand why I keep seeing the "well, you bought a sportscar..." cop-out.

The issue is that hp/lb/gal, we are way under everything else out there and the EPA rated us much higher than what nearly everyone is experiencing.
So, we are curious.
I don't think there are too many people here that are so concerned that they would give their RX-8 back if given that option.

I have over 12k on my 8 with A/T and I use 87oct most of the time though I feel a little more power with 91oct gas. New with the cruz at 65 and A/C on I got 23.5mpg. I was happy, but it got much better! Now with same conditions I have on 3 seperate tanks got 27.5mpg. It's hard to just set there in the slow lane. People think "He's got tickets" or " He's breaking it in" or is "He's going for what can this thing really get gas mileage wise?" Most of the time I get 18-23mpg. Tomorrow I have a long streach that I have to do 55-60mph on. I'm going to set the cruz and see if it can do any better. The thing is I will be at 2000 to 2500 rpms and the torque is low and mpg might not be any better. I will let you know tomorrow.....

45pence thats in the uk.

try reading the elise forum to see how we do things over in the UK.

http://www.british-cars.co.uk/cgi-bin/gen5?runprog=lotusbbs&access=&mode=tlist&subject=2001

We seem to be more obsessed with improving performance and avoiding speeding fines than MPG but like someone said we all like different flavours of icecream. :cool:

By the way has anyone got a spare rotary engine to pop into elise cos then you'll have some serious performance with such an improved power/weight ratio

Yep I did the below 3500 rpm thingy for half a tank and it certainly makes a big difference. 1 injector and good gas mileage! So folks all I can add for a cent is that it all revolves around the weight of our big feet! All the traction control aids off will make no difference except in the mind, the car SEEMS faster due to slip and sliding at full throttle.

How do i turn the dcs and tcs off, i have an automatic rx-8. Please reply or email me at qdog145@aol.com. i am very intersted and thankful that you mentioned this

If this is true, let's do a poll of users to find a trend on whether driving without DSC/TC will yield better fuel efficiency/performance. The poll would ask who has the base 6MT model and what is their mileage so far as all base models do not come with DSC/TC.


2004 Manual 6 Spd GT ( no mods except a green drop in filter)

Hey Guys,

Responding to the poll question and wanted to see if I was not alone on this. I have learned a lot of great stuff from all the threads and this one here seems to be on of the most interesting. So I am trying this test! I switched off the dsc/tc system every time i got in to the car ( for a period of about 1 week) and wanted to see how far it would get me ....guess what I pulled of about 21.22 miles to the gallon! Which was great. I did not baby the car either on at least a couple of occasions I would redline it between 1,2-3rd, both ways to and from work. Prior to I have been averaging about 18-19 miles to the gallon. I use 91 premium, live here in Toronto Canada and drive about 60/40 split city/ highway. It definately seems to work and maybe I need to get the car dyno'd first but it sure seems to have a better punch on take off and gets through the revband a lot sooner. Also I was wondering with the traction system turned on does the computer retard the timing on the engine to prevent excessive spin, just curious.


Hope this helps.

There's a post in the beginning of this that mentions if a purchase took place before August 26th you could receive a refund of 500 dollars and maintenance on the vehicle. What year does that date fall in?

I purchased my 8 at the end of march of 05.

There's a post in the beginning of this that mentions if a purchase took place before August 26th you could receive a refund of 500 dollars and maintenance on the vehicle. What year does that date fall in?

I purchased my 8 at the end of march of 05.

That year was 2003, so before August 26th 2003.

(holy dead thread batman, btw)

There's a post in the beginning of this that mentions if a purchase took place before August 26th you could receive a refund of 500 dollars and maintenance on the vehicle. What year does that date fall in?

I purchased my 8 at the end of march of 05.


August 24th of 2003

Looks like being the new kid on the block finds me at the end here...Just bought my '05 RX-8 three days ago and noticed that the fuel indicator dropped more quickly than I had expected. It sounds as though keeping the shifting to around 3000-3500 probably ensures the best mpg when that is important?

Looks like being the new kid on the block finds me at the end here...Just bought my '05 RX-8 three days ago and noticed that the fuel indicator dropped more quickly than I had expected. It sounds as though keeping the shifting to around 3000-3500 probably ensures the best mpg when that is important?
Barry, don't worry about your MPG with this car. If you shift that early you could risk lugging your engine and causing more harm than good.

Besides you should be able to rag on it pretty hard and still get 17-18mpg. If not, check your tire pressures, or maybe you've got a bad apple. Have fun with your new car!

45pence thats in the uk.


Dang, where do you get it? I am over here (US Military) and it's 95p / liter. Thankfully I don't have to buy it, since I just get my gas on base.

I love the car. And I hate the car. My only problem has been the mpg ( and the summer tires, but that I can change).

City driving, Brooklyn to Manhattan, 12mpg at best. I get 160 miles a tank.

Highways, NJ shore to manhattan during summer: 16 mpg at best.

I have driven the car balls-out, WOT, for two tanks, city driving: 10.9 mpg.

Driving style, tire pressue, revving hig or low. Nothing makes a difference. (I'll try diabling the traction control, maybe it will help...)

Mazda USA says they defer to the dealer when troubleshooting problems. My dealer said, " Nothing's wrong with the car. Fuel system etc is within spec. You have to live with it."

I don't want to complain anymore. This mpg issue has soured me on the whole car and is keeping me from spending ANY money on upgrades and performance parts. The aftermarket has lost me as a customer.

It can't be that people are getting 18mpg city and I get 12mpg, and both cars are "normal".

Something is wrong with my car. No one wants to help.

What do I do? Trade it for an '06 RX8 and hope it's better? Trade it for an Acura TL? Or a Jeep Cherokee with a HEMI engine? Or a BMW X5 4.6?


Such problems.....

Heh ... this is the first thread I ever read when I was a noob back in 2003.

Beefyjoe ... let me ask you something ... what's the traffic like in NY? My guess is stop and go, bumper to bumper with lots of idle. Then that's no doubt you're getting such crappy mileage. In that instance, it's not your fault. Maybe ask some of the local NY guys in your area that do similar drives to see what they are getting. Not sure what's going down with your highway driving though ... what RPM are you using?

Highway? I cruise along in 3rd.... :hahano:

All I can say is, my driving is normal. I shift to 6th as soon as practical.

The real burn is that when I drove WOT all the time, for two tanks, I got 10.9 mpg - only 10% off my normal city mpg.

So my car ranges between 12 and 10.9 for city driving. That really sucks. :mad:

Beefy,
Are you doing an extended warm-up before leaing home (Five or ore minutes)? My first tank was 13 mpg but all I did was drive it out of our building on mornings and drive it back in on evenings, letting it warm up 5 to 15 minutes for 2 weeks and taking it to my home on the weekend Now that I'm using it more, things have improved I just got 19.2 on my last tank that was mostly highway with some spirited stuff thrown in as well.
A general rule in the autmotive game is don't start your car and leave it idling to warm-up unless you have no option, like you live right next to a highway that you must use and merging requires heavy throttle input or something.
Paul.

Beefy I think you were making a joke (big smiley)... but if you're serious then for your highway, IMO 3rd gear is too low to cruise in. I don't know what the exact speeds you're travelling at but I know if were to go 100km/h or roughly 60mph (i think), my rpm would be near the top 1/3 of the rev range. At 100km/h in 6th gear, my RPM would be in the 3000 range. So perhaps this is where you're burning all your gas during highways.

OH, just thought of something ... how old is your car and how much on the odo? I remember when I first got the car, during the break in period the mileage was HORRID (12-13mpg). As the mileage accumilated the consumption improved.

I think everyone was saying around 3k miles there was a sudden large improvement in mileage.

I avg 17-19 mpg now. I saw the improvement around 10K miles. When I first got my car, I got 12mpg too...it DOES get better

I've had my car for a little over two weeks. I do about 75/25% Highway/city and have been averaging 16mpg. Usually average about 80-85mph, 6th gear @ about 400rpm... I have about 1000 miles on it and I hope it will get better as it breaks in. I'm in MI and we have snow.... So it will be a while until I can try disengaging the DSC.


Question: does it always reset when you turn the car off?

so by holding it for 5 seconds we can turn it off... but what about turning it back on? just hit the switch?

i'll be downstairs to test it out but what if it doesn turn back on again? haha

I live in a semi-rural area, so I don't have a lot of traffic lights. I do a lot of highway driving when I drive into town. I'm averaging 19mpg with about 1,000 miles on my car.

so by holding it for 5 seconds we can turn it off... but what about turning it back on? just hit the switch?

i'll be downstairs to test it out but what if it doesn turn back on again? haha

Turn the car off and back on again (I've actually done this while rolling down the road at 80mph when it started raining - I drive a manual).

Notice the manual never tells you how to fully defeat the DSC/TSC. It says something like if the TSC light stays on turn the car off, then turn it back on again -like there's a problem with the DSC/TSC. This is probably for legal/safety reasons.

After reading 10 pages of this thread I gave up. But the reason for the increase in mileage with the DSC/TSC off is most likely due to more conservative driving to prevent wheel slippage or sliding.

Should I let me car warm up or not? In the mornings when i go to work i hop in the car, turn it on and go. I average about 16.5 mpg (50/50 highway/street) no matter what i do. I can shift at 3500 rpms and get 16.5, i can drive like a 16 yr old in a ferrari and get 16.5 mpg, i can do 100% highway and get 16.5 mpg. It's crazy. My car loves the 16's. Yes yes, a few times i'll get 16.3, or 16.7 or something like that, but it always averages out to 16.5.

I've never once let me car warm up. I've come from BMW's and they say never let a car warm up by just idling.

I've never once let me car warm up. I've come from BMW's and they say never let a car warm up by just idling.

I've read this same thing many times in car magazines, but I probably wouldn't take it to 9000 rpm until it has had a minute or three to warm up.

I've read this same thing many times in car magazines, but I probably wouldn't take it to 9000 rpm until it has had a minute or three to warm up.

Oh I give the car at least 10 minutes to warm up before i get on it.

I dont drive it hard til it warms up for a minute or so

I've read this same thing many times in car magazines, but I probably wouldn't take it to 9000 rpm until it has had a minute or three to warm up.

Actually you can't... I know because it freaked me the hell out this morning!
I was late for work and didn't let it sit for very long before I took off.

As I went down the street in first gear, i hit 6.5K and the engine cut out like it does if you redline it. I was shocked! I tried it again and the same thing hapened. About ten min later when the car had warmed up I tried it again and it had no problem at all. So this car is so smart it won't let you over rev a cold engine! Now that's pretty sweet.
G

Actually you can't... I know because it freaked me the hell out this morning!
I was late for work and didn't let it sit for very long before I took off.

As I went down the street in first gear, i hit 6.5K and the engine cut out like it does if you redline it. I was shocked! I tried it again and the same thing hapened. About ten min later when the car had warmed up I tried it again and it had no problem at all. So this car is so smart it won't let you over rev a cold engine! Now that's pretty sweet.
G

This feature is explained in the owner's manual. :stickpoke

This is very interesting and I certainly will try it. Another trick you may try is removing the engine cover. A few weeks back I was in a hurry and after putting in some oil I failed to put the cover back on. Result...my overall milage jumped from 16/17 to 21/22. Not sure why, maybe better air flow. At first I thought maybe it was a fluke, but i've driving it now this way through at least 6 tanks and it has yet to drop. Try it out and let me know if it works for you. Goodluck.

I have no engine cover on mine, doesn't seem to help any, in fact it seems to take longer for my engine to warm up. However, I will try disabling system to see how that does.

Removing the engine cover reduces the airflow through the engine compartment and raises engine compartment temps. It also exposes your hood to higher temps. This is not advisable for anyone in hot climates for sure.

This is very interesting and I certainly will try it. Another trick you may try is removing the engine cover. A few weeks back I was in a hurry and after putting in some oil I failed to put the cover back on. Result...my overall milage jumped from 16/17 to 21/22. Not sure why, maybe better air flow. At first I thought maybe it was a fluke, but i've driving it now this way through at least 6 tanks and it has yet to drop. Try it out and let me know if it works for you. Goodluck.

very interesting

I just can't really see that happening MazdaManiac.... But who knows... A lot of things on the RX-8 serve a purpose.

This is very interesting and I certainly will try it. Another trick you may try is removing the engine cover. A few weeks back I was in a hurry and after putting in some oil I failed to put the cover back on. Result...my overall mileage jumped from 16/17 to 21/22. Not sure why, maybe better air flow. At first I thought maybe it was a fluke, but I've driving it now this way through at least 6 tanks and it has yet to drop. Try it out and let me know if it works for you. Goodluck.

Bruiser wins the inaugural Gomez Award. This award will be e-presented annually to the most ridiculous claim made on this forum.

Congratulations Bruiser1255...... :rolleyes: :rolleyes:

Bruiser wins the inaugural Gomez Award. This award will be e-presented annually to the most ridiculous claim made on this forum.

Congratulations Bruiser1255...... :rolleyes: :rolleyes:That's nothing. I once forgot to fasten my seatbelt and managed to get 24 miles per gallon, instead of the usual 18.

I dare you to doubt my claim.

My milage improves when I fart...

Extra "gas" I suppose... :bootyshak

That's nothing. I once forgot to fasten my seatbelt and managed to get 24 miles per gallon, instead of the usual 18.

I dare you to doubt my claim.

OK JH, in honour of your momentous achievement in fuel conservation, I'll implement a change in the frequency of the award e-ceremony.

You win the Gomez Award for the hour of 0200 UTC, 18 Jan 2006. It's probably a good thing I give these awards out hourly, there are quite a lot of bullshit claims on the forum :naughty:

Cheers,
Gomez.

That's nothing. I once forgot to fasten my seatbelt and managed to get 24 miles per gallon, instead of the usual 18.

I dare you to doubt my claim.

I wish I got18 MPG!! I've been in the 13 - 14 MPG range! And i don't even drive her that hard! ;)

My milage improves when I fart...

Extra "gas" I suppose... :bootyshak
The *weird* thing is... MY mileage improves when you fart!

I have yet to break the 200 mile mark to a tank of gas. My tank is bone dry at the 198 mile mark. When I fill it the pump shuts off at 14.3 gallons. So I'm getting 14MPG. Thats just about all city driving. Don't understand how people are getting 18MPG city driving...I dont drive the car hard

I'll try turning off DSC/TC on my next tank and see what happens....

I swear, the only reason people will see an improvement is because they're being more careful with DSC/Trac off.

The *weird* thing is... MY mileage improves when you fart!

:lach:


Glad to be of service...

BTW, turning off DSC/TC sounds like a BAD way to save gas...

I'm looking forward to seeing how the UK model behaves in these circumstances. First, any MPG figures I report will be based on Imperial, not US, measurements - to compare I multiply the US figures x 1.2, which certainly gives me hope for getting reasonable consumption from my car.

EDIT: Before anyone says "the multiplication won't change the consumption" - I know. I mean, that if I got around 23mpg in UK terms I'd be happy - so 23mp(US)g looks like a good figure to me.

Secondly... I haven't driven a powerful RWD car for some time. My Supra may have claimed to have 200bhp, but it was a lardy automatic thing, and quite old - I very much doubt it was really generating that much power. I'm torn on whether or not I will have the reactions/connection to drive enthusiastically with the DSC off, but I also think that learning the car's handling with DSC off is the way to go. I drove my X1/9 enthusiastically without any driver aids, same goes for my 924S, Manta and other cars.

My Beetle has traction and stability controls. With them off, it really does handle like a pig, which makes me think that in fact, they are only intrusive when you do something it interprets as silly, but are doing something all the time.

Gah, this is going to be the longest month EVER.

Well gents, I find this thread very interesting. We have two 8s both are base model 6 speed units. My wife and I both get 20-22 mpg regularly. While we do not get the chance to run curves alot, we do drive on the high side of 80, a l o t.... As stated, both cars are the base model units so neither have DSC or TCS. I have always wondered why our mileage was above the norm. I think that there should be some additional research done on these systems.

Lastly, we don't miss having them.

I have a base 8 and I get 14-16 MPG...

the dealer asked me if i wanted one with tcs i said f no my right foot is my tcs.

the dealer asked me if i wanted one with tcs i said f no my right foot is my tcs.Please post the inevitable pic.. thanks..

Twin 8's --
My GT gets 21-22 mpg consistantly, and just leave the DSC on all the time. That's using 87 Shell.

I cant believe this useless thread is still alive :Kill2: :Kill2:

It was established ages back that turning off your DSC has no impact on your MPG.

Mods, please lock this thread...!! Die thread, Die..... :rl: :rl:

Twin 8's --
My GT gets 21-22 mpg consistantly, and just leave the DSC on all the time. That's using 87 Shell.

Probably because you are using the not recomended lower Octaine gass.

87 will not burn as fast as 92/93 there for you will certainly get better gas milage.
That's still pretty high and hard to believe but you probably do a lot of highway driving and not so heavy on the gas.