WTF!

I know this has been beaten to death but I just needed to share this you guys and gals and also get your opinions on what I just observed.

I was finaly able to get my 8 out on an "extended" road trip this past weekend. I drove to the Short pump mall in Richmond VA from my home in Newport news.

Now normaly one would think that the more highway miles driven on a tank the better the mpg or for that matter being able to get more miles driven on that tank. But nooooooo, not with this car!

On my last tank (19 Feb) I drove mostly city driving with one 70 mile round trip to VA beach. I drove 245.3 miles on that tank over a period of eight days. Now the last tank I got the following:

Miles driven: 245.3, Fuel used: 12.820, MPG: 19.83

Now this past fill up (on 27 Feb) The total miles driven includes the trip to Richmond (and then some) which was 198 miles round trip, straight highway driving while using the cruise control, driving at 70-75 mph for most of the trip. In three days of driving I got the following:

Miles driven: 253.0, Fuel used: 12.608, MPG: 20.079

Technicaly I was only able to get the same miles (253 vs. 245.3) per tank between the two fillups. The low fuel light came on just before filling up on both tanks. The mpg was for the most part the same whether I drove 70 miles or 198 miles highway between tanks. I only saw a .249 mpg increase for 128 miles more miles driven at highway speeds.

You would think I would have gotten better mpg or at least more miles on the tank while driving more highway miles. This is totaly whacked!

P.S. I actually heard the RPM warning buzzer during a spirited jaunt on I95! Whoo hoo!

you're into the rich 2nd intake open maps when at 75. try cruise at 65 next time . you should be able to get 24 or better there depending on conditions. btw same gas and octane between those 2 tanks?

OK, I just went on a road trip and cruised at around 75-77 and was able to pull off a tank full at 300.5 miles. It took 14.11 US gallons. That's 21.3 mpg, a record for my 8 and I was traveling into a slight head wind. I was close to running out of gas by my caculations and stopped at the first station as soon as pulling into town.

My mileage on the whole trip never went below 20 and I did it all at 75-77 mph. I will never complain about the gas mileage again, it only sucks in town even if I granny drive which I ain't no granny.

i have no complaints on the highway. i get 20-21 highway at 65-75 MPH but 100% city is bad. 12-13 MPG but my commute is 5 miles each way. by the time its warmed up i'm at work and shutting it down. i'm taking it in on the 12th for the 2 recalls, brake squeal, clutch noise(when not engaged) and i'll ask about the ECU flash then.

Zoom 44 - yes the same station, same 89 octane

D MENAC 7 - My low fuel light comes on at the same point and always takes the same amount of fuel (12.5 gals) so how can you get 14.11 on the tank. Didn't you not get the low fuel light?

Oh, I got the low fuel light and I was 35 miles out of town. Don't think that last 10 I wasn't making plans on who was the closest who could come and bail my ass out. LOL I was starting to sweat it and did slow down to 65 and drafted a huge RV for that last few miles.

Oh yeah, 87 octane all the way there and back.

In town, just like RX-GR8, I get 13-14 mph and I also have a short commute with about 6-7 miles one way but a lot of lights and stopping and going.

all my 8 has ever seen is 93 octane. menac have you ever tried 89 or above? why 87?

hell i put 1/2 gallon less than capacity in after doing 310-315 in mine with the light on for the last 9 miles. most of the last 25 were on regular roads not higways. it was super scary at night in unfamiliar area in northern cali with my wife glaring at me from the passenger seat. wont push it like that again- wife would hurt me really bad.

Yes, I have tried 89, 90 and 92 and none have proven any more or less for the way it runs or the gas mileage.

Why 87? I have read the thread on here about 87 and it seems to do just fine. Why pay more for nothing in mileage or performance. I have recorded all my tankfulls and driving habits and cannot see any varience.

Originally posted by zoom44
hell i put 1/2 gallon less than capacity in after doing 310-315 in mine with the light on for the last 9 miles. most of the last 25 were on regular roads not higways. it was super scary at night in unfamiliar area in northern cali with my wife glaring at me from the passenger seat. wont push it like that again- wife would hurt me really bad.

Yeah, my wife was there and I assured her we would make it. I had her believing me more than I believed myself, didn't sweat it, I am a good poker player. :)

i was sweating buckets and she could tell even in the dark. i kept saying "we'll make it dont worry" but i really had my doubts.

I've driven 12000 miles so far. Every single tank except maybe the first 2 or 3 has been between 18 and 21MPG, with the vast majority being about 19.5. Many different types of city/hwy driving, and I take it to 9K whenever I can.

Originally posted by D MENAC 7
Yes, I have tried 89, 90 and 92 and none have proven any more or less for the way it runs or the gas mileage.

Why 87? I have read the thread on here about 87 and it seems to do just fine. Why pay more for nothing in mileage or performance. I have recorded all my tankfulls and driving habits and cannot see any varience.

yea i read that thread too. just was wondering if there was a performance loss and a MPG gain from using it.

I don't understand the panic about the low fuel light. Sure, I fill up soon after I see it -- why not get it over with? -- but I'm not afraid I'll run out of gas.

Instrument readings and mileage claims may not be reliable, but when a car manufacturer says its tank holds 15.9 gallons, it holds 15.9 gallons. That doesn't vary in production; it doesn't shrink with age. 15.9.

Once you have seen the light on your car a few times, and noted how much less a full fillup is than 15.9, and made sure it is about the same amount under 15.9 each time (in other words, that your light comes on at the same point each time), you can be damned sure how much gas is left.

The miles left calculation is pretty exact, too. Based on mileage before the light comes on and the kind of driving you have been doing, you can tell if the car is giving the same mileage it has in the past. Then you just apply that past mileage to the kind of driving you will be doing with the light on, and you know how many miles you can drive before it really goes dry.

Think, then relax.

Ahhh, I couldn't remember how large the tank was, I thought it was in the 14.5 gallons, not 15.9. Hell, I didn't have to sweat at all then. I didn't have my manual so I just didn't really know. That needle was past empty and I haven't had my car long enough to know it that well. So, from now on, I have a better understanding.

My wife does bitch at me once in a while that I shouldn't let the tank get so low that it isn't good for the car. I always wondered about that because I hardly ever fill up before it's almost to the E.

She claims her mechanic Father always said that it wasn't good and I always argued that with todays's car's fuel injection and computer management it didn't matter. What does anyone think about that??

I've been told that the RX-8 begins to run very lean at 4200 RPM, after your break the 4200 RPM barrier it starts to inject more fuel. Keep it under 4200 RPM and you should get better fuel econ.

[QUOTE]Originally posted by Rotary Nut
[B]WTF!

I know this has been beaten to death but I just needed to share this you guys and gals and also get your opinions on what I just observed.

I was finaly able to get my 8 out on an "extended" road trip this past weekend. I drove to the Short pump mall in Richmond VA from my home in Newport news.

--------------------------------

short pump mall????

god how it must have changed, short pump was just a place you might get gas on the way back from wintergreen. a mall, thats wack.

as to the milage issue. for me worst 18mpg best 23mpg. most lite city with ac.

i think if you go above 75mph. it goes down.

beers

Originally posted by Rotary Nut

P.S. I actually heard the RPM warning buzzer during a spirited jaunt on I95! Whoo hoo!

probably lost a gallon right there! :D

I just got 25.0 mpg on a trip to Dubuque, IA. It was mostly 2 lane roads. I cruised at 60-65. It you go over 70 you RPM goes to high and you really burn the fuel.

Hell, I wouldn't complain if I say anything near 19-20 mpg. I've observed 14.5-15 mpg since I bought the car, with one tank dipping down to 13. The last tank consisted mostly of hwy miles driving a 35 mile stretch each way for the most part and still barely cracked 15! Gotta look into getting that ECU reflash.

Originally posted by RX-GR8
yea i read that thread too. just was wondering if there was a performance loss and a MPG gain from using it.

I have not noticed any appreciable performance loss by using 87 octane. I have considered putting an octane booster in just to see what that would do but just have never taken the oportunity to do anything abouut that. If I do, I would want to do it with a bit of semi-accurate testing, not that I can do it to the nth degree because I do not have any real test equipment. It would have to be done with the seat of my pants observation.

Does the RX8 have a trip computer that measures average MPG?

-Eric

Nope. Trip computers A and B only measure miles traveled since reset. Mazda didn't include the Average or Instantaneous MPG or speed functions. Too bad.

m

Originally posted by Positron
Nope. Trip computers A and B only measure miles traveled since reset. Mazda didn't include the Average or Instantaneous MPG or speed functions. Too bad.

m

they were afraid to include that feature:D

I've achieved urban and combined gov mpg figures in my UK car and others have acheived 30mpg (uk gallons) not far off 32mpg max as stated by gov.

It takes a whole lot of patience, slow acceleration, changing below 3750rpm, accelerating slowly, not revving high , accelerating slowly...

When I tried I got 25% more miles out of my tank than normal (250 instead of 200). Was THE most boring tank of fuel but you CAN acheive the right numbers if you try. Dont expect economy if you trigger the 2nd fuel injector.

Originally posted by MaRX8
I've been told that the RX-8 begins to run very lean at 4200 RPM, after your break the 4200 RPM barrier it starts to inject more fuel. Keep it under 4200 RPM and you should get better fuel econ.

At 70 mph she was barely turning 3100 rpm so that can't be the problem!

Correction: at 70 mph in 6trh gear you would be turning around 3500 rpm. But your point is valid - the secondary injectors still shouldn't be a factor.

Everybody talks about when the secondary injectors cut in, but
is the auto and stick shift the same? My auto at 3,000 RPM is doing 73mph. This must be one of the reasons the auto is rated at more mpg!

Got to love Mazda dealers...

I called mine today. Talked to the Service Manager. I advised him I was getting terrible gas mileage. He said "No kidding? We haven't been getting any complaints."
Tom

Originally posted by DemonRX-8
Hell, I wouldn't complain if I say anything near 19-20 mpg. I've observed 14.5-15 mpg since I bought the car, with one tank dipping down to 13. The last tank consisted mostly of hwy miles driving a 35 mile stretch each way for the most part and still barely cracked 15! Gotta look into getting that ECU reflash.

I hear ya bro...

I'm the same way.

Just tell them it's been idling rough and starting hard... or some similar line. I'm sure they'll look at it and probably re-flash (hopefully)

I do have a newer flash, if not the newest, the one right before. I did some spirited drving this past weekend on some country river roads, in and out of the valleys. A lot of 7-8k runs and managed 16.6 mpg. I have not been on strickly hwy for sometime, which I did get 21 mpg before hitting 1000 miles.

It does appear to be getting better as the mileage increases, and I jsut started to use 89 oct for the last 2 tanks and it runs as good as ever.

Originally posted by DemonRX-8
Correction: at 70 mph in 6trh gear you would be turning around 3500 rpm. But your point is valid - the secondary injectors still shouldn't be a factor.

Well correction back at cha! That would be nice IF I HAD A SIXTH GEAR!

Check my sig I have an Automatic!

:D

Im sorry but the MPG issue is not getting silly when its claimed that this car gets per say 24 mpg on the highway (automatic) and I am getting 12-14 mpg on the highway... I just dont see how its getting silly... I dont find it funny... I want at least 19 MPG for a car of this size... and when you say you bought this car dont expect X amount of MPG, I would understand that IF THEY SAID THE CORRECT MPG ON THE STICKER!!!

Originally posted by Mitch Strickler
Instrument readings and mileage claims may not be reliable, but when a car manufacturer says its tank holds 15.9 gallons, it holds 15.9 gallons. That doesn't vary in production; it doesn't shrink with age. 15.9.

Once you have seen the light on your car a few times, and noted how much less a full fillup is than 15.9, and made sure it is about the same amount under 15.9 each time (in other words, that your light comes on at the same point each time), you can be damned sure how much gas is left.

The miles left calculation is pretty exact, too. Based on mileage before the light comes on and the kind of driving you have been doing, you can tell if the car is giving the same mileage it has in the past. Then you just apply that past mileage to the kind of driving you will be doing with the light on, and you know how many miles you can drive before it really goes dry.

Think, then relax.


Just because the tank can actually hold 15.9 gallons, it doesn't mean that the fuel pump can actually suck all 15.9 gallons out of it before starving and cutting out.

Keep that in mind...

Originally posted by jniamehr
Im sorry but the MPG issue is not getting silly when its claimed that this car gets per say 24 mpg on the highway (automatic) and I am getting 12-14 mpg on the highway... I just dont see how its getting silly... I dont find it funny... I want at least 19 MPG for a car of this size... and when you say you bought this car dont expect X amount of MPG, I would understand that IF THEY SAID THE CORRECT MPG ON THE STICKER!!!

I understand your issue.
If you are getting 12-14 on the highway, then something is wrong with your car. I think that most people are getting 20+ on the highway.

Most of the MPG issues people have rasised are that they get slightly less the EPA ratings, most get 20-22 on HW and 16-18 city. 12-14 is a problem.

(Heck, I get 16 in what I would call City, but actually Country driving. And I redline all the time, I never shift below 7K unless stuck in traffic. Country roads are fun :)

Visited with the Service manager at the Dealer this AM. He checked with Mazda and Mazda claims the L flash is ONLY a fix for a CAT error code. Will not do anything for mpg. He will do the flash on my car, based on the antidotal reports I gave him, the lack of other alternatives, and my very poor mpg. But doesn't think Mazda will do anything about mpg until they come up with a reflash for the high number of flooded non starters coming in. He's betting they will sneak it into that flash.

Originally posted by jniamehr
I would understand that IF THEY SAID THE CORRECT MPG ON THE STICKER!!!

Just a reminder... "THEY" is the EPA not Mazda, and YES the EPA estimates are pretty much fiction.... Mazda has nothing to say about them, they just submit the car, take home the result, stick it on the sticker. That's the law, love it or hate it.

If you have been reading on another thread, Prius and other hybrid owners are complaining too, not getting their 60mph and all, I think only 35-40 or so.

I don't think anyone's accused me of granny driving, and my RX-8 consistently returns 18 to 20mpg around town. On a recent road trip, I got around 22mpg. While I think it would have been nice to have gotten 24mpg, I think that would have reduced the entertainment value just a smidgen to much.

Whoa buddy - This thread is like 2 years old.


Hey, atleast you searched..

Matt Damon!

Just to add more confusion: The RX-8 in the UK is rated 18.1 mpg city and 32.5 mpg(!) "extra urban" - which I think means highway.

20+ highway?

Does everyone drive like some little old lady?

If you do below 80 on the turnpike here, you are ROADKILL. I average between 88 and 105 on the turnpike... 65? Don't make me laugh. Thats a fucking obscenely slow speed for anyone on the highway.. I do that on SURFACE streets, and then some.

I wish we had a real 6th gear.. because the mpg thing is really kinda insane.. even when I *try* on the highway.. 19mpg even. There is no way in hell I or anyone should have to drive unsafely slow to get a reasonable mileage. And 65 IS unsafely slow. Just try to do 65 on I-95 and lemme know how that works out for ya...

Psy, you are absolutely correct. My experience as well. Jersey pike (I assume?) is 80-90+ mph REAL speed limit. You go under that, and you'll get run off the road. Even growing up in the DC Metro area and being weaned on the traffic here, it shocked me up there. Crazy people.

I-95 and beltway around DC isn't quite as intense, despite still being crowded and often insane. Around here it's 65-75 in the 55 zone as the "real" speed.

lolo.. i thought i was the only one getting 12mpg on highway. i used to get 14mpg witht the m flash, but now with the r i get less. go figure... at least i have more power :)

denward

Just to add more confusion: The RX-8 in the UK is rated 18.1 mpg city and 32.5 mpg(!) "extra urban" - which I think means highway.
That's not directly relevant - an Imperial Gallon is 20% bigger than a US gallon! Of course the UK rating per gallon will be higher, for that reason alone.

(1 Imperial gallon = 1.2 US gallon
1 Imperial gallon = 4.546 litres
1 US gallon = 3.785 litres )

A UK rating of 32.5 miles per Imperial gallon is the same as 27 miles per US gallon.

Regards,
Gordon

I haven't talked about this issue for months as I quit worring when I realized there was little I could do about the 10-11 mpg I was getting in town.It had been tested by the dealer and everything and they varified the low milage but could find no problem. I was driving many short trips and back and forth 3 miles to work. Then a couple of things changed. I moved and now drive 10 miles each way. I got the Recall and new flash. Now Im getting 14-15 in town. Honestly I am almost sure that part was the longer trip and part is the more recent flashes. In any case I am very happy. I now have 9500 on my car and that may also be a factor. I definetly saw a change after the M flash. I've had the newer flash for three weeks and things are about the same. That is except I now have a blanket under my gas tank. lol