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:

mmjames

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

RX-GR8

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.

Rudenauer

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?

Genom

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

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!!

PoLaK

iTrader: (1)

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.

Wing

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!

TJRX8

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.

RotorGeek

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

nk_Rx8

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.

JeRKy 8 Owner

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?

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:
I would also like to quote myself from 8-18-03 in a huge thread about dyno results called R&D here:
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...

Tronics

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.

TJRX8

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.

mikeb

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

pelucidor

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.

ramfann

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

Shocka

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.

mmjames

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

Charles Cope

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

RobDickinson

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

rxeightr

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.

meat

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.

downshift

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.