310Guy

Why wouldn't the PCM "reset" to the driving habits without disconnecting the battery? I'm not saying over one tank but if you've changed your habits for two or three tanks (approximately 500+ miles), wouldn't the PCM correct itself?

Silver04RX8

180-200miles per tank people, drive it like you stole it.

guy321

Wouldn't you rather know for sure than to guess?

It is part of the scientific method to return your experiment to a baseline before making changes.


Also, this was just a helpful suggestion. Use it or don't. I really don't care.

StewC625

OK: Results:

I honestly didn't see much difference. Maybe I didn't do it right but I tried to drive at 3500 RPM at all opportunities - picking the right gear, and adjusting speed to get there - about 70 on the highway in 6th, 55 on a side highways in 5th, 45 on the arterials in 4th, 35 on the main streets in 3rd and 25 on the residentials in 2nd.

My tankfull that I tested this on got me to 224 miles before the light went on - this on Chicago reformulated gas, which always delivers shitty mileage - at least a 10% drop in mileage - or more.

Ok, now that all said, my normal mileage to the empty light is about 205, so 20 more miles per tank IS a 10% increase - but not nearly as much of an increase as I expected, and not worth the hassle of trying to pick the right gear, staying under 70 on the highway (I run 85 or greater most of the time on the open interstate), etc.

alnielsen

iTrader: (4)

To me the problem isn't so much the mileage issue, but the 15 gal tank. Don't get me wrong I would like to get more than 15 mpg. But a 17 to 18 gal gas tank would be better.

Xyntax

Yup, I've done this experiment and I have gotten great results. My problem is this though. Because I have been used to less MPG, the moment I realized that I have more to go after the half tank, I get all excited and rev to 9K a lot and even cruise at 5K for some time. I dont know, it's silly, but the car just pushes you to drive it harder once you get to that "sweet range". It's an evil car I tell ya.

I no longer drive under 3K, both for sanity and mileage. I can't stand how differently it feels to drive under the 3250 range, it sucks for the lack of a better term. I was also getting the worst mileage back then when I cruised at 6th gear at 45mph coz I thought it was going to save me gas.

Like I said in several threads, its not the price of gas or low gas mileage that really bothers me so much... it's the frequent visits to the gas pump. I kinda wish this car has larger gas tanks.

NgoRX8

iTrader: (1)

yes it would be so much better. the hill up to my house kills me, im getting 13-14s right now. its my first tank, so ill see if there's a difference next time.

RotorGeek

I.ve done this the past 2 week and have gotten 50 more miles per tank.

Feras

iTrader: (1)

call me a little bit of a braggart, but i enjoy going to the gas station and talking to people about my car. (happens a lot)

StewC625

oh thank god! I thought I was the only one that enjoyed that ...

I did this expermment and it does make a difference - but ... read this next little bit, THEN I'll show my results.

Recently, in Car & Driver there was a big article about gas mileage, hybrids, the EPA cycle, etc. One thing they recommended is quit thinking in terms of MPG but instead of "gallonage per distance" - because that's where driving habit changes really show. - The example they gave is that for a typical SUV driver, a minor change in driving habits may result in a 15% difference in gas mileage. However, because you're only getting 10 mpg out of that ExpesuburaH2, improving to 12 mpg doesn't seem like much improvement. BUT - over a distance, that really adds up - or over a tankful. A 40 gallon load of fuel at 10 mpg lasts but 400 miles but at 12 mpg, you go another 80 miles on that same tank load.

So goes the test results here. My typical "all city cycle" mileage is about 200-210 miles per tank until the fuel light comes on - about 16.5 mpg. Using this technique got me to about 18 mpg - doesn't seem like a big difference, but seeing that magic "250" on the trip odo before the fuel light came on WAS a big difference.

Yes, it's all in the psychology of the numbers. But mileage/fuel consumption changes are much easier to spot and much more impactful when you see a change like that! It's the reason that the traditional "metric" way of measuring fuel consumption is not "KM per Liter" (as the incremental changes would be two decimal places down), but instead "Liters per 100 Km" - because the consumption can be more easily noticed that way.

FYI

rx8daniel

'braggart'
I live in an area that is far less of a 'car place' than most larger American cities. What I mean by that is few people notice any cars, period, much less know or care what they are. That said, I do get an occasional comment on the car. But I'm seeing more of them on the road lately so those occasions are dwindling to next to nothing. But that's because of where I live, nothing to do with the car being less appreciated by those who care.
anyway-for my part of the experiment-I had quite a few more miles around 60MPH that I used 5th instead of 6th. My mileage suffered. I was under 19-about 18.6 I think. Next tank I still tried to keep the 3250-3750 range in town, but at 55+ I used 6th again. That tank was about 19.7. It appears it didn't help my own situation. So in town when I might normally be in the low 2000s I'll keep it a gear lower to keep in the upper 2000s or lower 3000s - which is really a very small change. I'll see how that plays out over the next several weeks. I'm thinking my normal way of shifting is close to the optimum based on what I know is going on with load, gearing and any immediate or near-term pending throttle requirements.

rx8wannahave

Thanks to the person, sorry I'm in a rush and I forgot the name, and everyone who cares about MPG. Yes, we know what sports cars are about and that MPG is not really the most important thing in a sports car but who does not care about SAVING MONEY?

I know it's not much, but those $20 a month can go towards something for the car (after you saved it up). You could save those $20 for when the 8 get's older and it needs repair.

If you save $20 a month on gas and save it you will have $240 for the year. Then after 5 years you will have $1200 to spend on repair (just in case) or better yet on some performance parts for the 8. (note, per one of the posts, it can increase to $40 for some drivers)

So, don't nock the person trying to get the most out of their 8 and don't have a money tree at home. Anyone that has not been rich all their lives understands that $20-40 per month is SWEET!!!

I don't have an 8 yet but this post was very helpful and has finally calmed me down on the MPG issue. Like I said in another post, it's in the driver and his/her habits how much fuel you use. Those that like running the car into the ground, go ahead, but please let me know so I don't end up buying one of your 8's. Anyone that loves sports cars will rev and play with them, for this is the reason we love them, but if you do it every stop light and/or punk who wants to race...then I"m sorry, but you are beating to heck out of that car of yours...don't cry when the tranny dies right after the warranty or the engine needs to be rebuilt after 60,000 miles. Any auto engineer would agree...

Play with your baby, but give it some TLC too...