zerobanger

Ok...

I didn't want to start another MPG thread but this one is different than the usual. If the mods dont like it, feel free to delete it.

I went to reno this weekend. I go there alot and over the last 2 years I have taken my 94 Rx-7 there probably every 3 months on average. This is the first time since buying the 8 I went, so I took the 8.

Its 230 miles each way. On the way there I hit some semi heavy traffic in sacramento. while it never got to the point I had to stop the car like stop and go, I had to slow down, pass and speed up a good bit for about 1 hour. Cruise control on for most of the trip (except sacramento) I got 23 MPG. I was around 65 MPH or 3300 RPM. This matched what I get for my FD exactly. Keep in mind this direction has some serious elevation to climb about the last hour prior to getting to reno.

On the way back I put the cruise control on from 58-62 MPH. I did this for 89 miles. There was no stop and go and during this time atleast half of it was a steep decline. It was about 33 F outside also if that matters. Just outside of sacramento when it was near flat again I put gas in my car and got a 26.3 MPG. I was very happy because my FD would get me 25 MPG.

Ok, so this is the interesting part. I drove the car for 95.2 miles before this fill up. The traffic was not bumper to bumper, there was only about 2 maybe 3 occasions I had to pass another car. I changed the cruise control to 60 MPH. or nearly exaclty 3000 RPM during this test. I could tell from watching the gauge that my gas mileage was way better. If you look at the gauge, there are large tick marks that seperate the gauge into quarters. When I pulled into the gas station at 95.2 Miles the needle was on the lower part of the 2nd large white tick mark, which is what I will refer to as the 1/4 mark.

So I filled up the tank, the same way I always do. As soon as the pump stops and I hear a "CLICK", its done. I dont put any more gas in after that. It came to 3.15 gallons. My gauge was again all the way to the top. There is no mistake and no miscalculation. It appears that 60 MPG in 6th gear is the key. You can go above that a few MPH but then it starts to eat more gas for some reason. Oh yea, while my FD gets 25 MPG at 3000 RPM during the same circumstances, its actually at 80 MPH vs the Rx-8's 60 MPH.

I used chevron 91 octain on all these tests.

BTW...this is one AMAZING engine.

Sea Ray

Sounds like my next trip anywhere will be at 60 mph! If you can duplicate this it would sure help make everyone a believer.

beachdog

zerobanger, sorry for being cynical, but I 'd like to see you duplicate the performance. since you don't top off the tank, you could be off. Different gas pumps have differnet sensitivities for the auto cutoff. Out west those pumps have a sealing cuff to prevent vapor from escaping and could easily be tripped before the tank is really at the top. My old car, a Mercury, could take 4-5 more gallons after the first time the pump tripped off.

zerobanger

thats another thing I forgot to mention. I would like for someone to do this. Drive it for 100 miles on a freeway both directions. Use cruisecontrol like I did.

Also if this matters when I had to speed up or slow down I rarely hit the brakes or the gas, instead I used pressed the cruise control either up or down to increase or decrease the speed. Its actually quite easy to do this and probably saved some gas. In situations where I did have to pass someone or had to slow down quicker I hit the gas/brakes.

I did this for a reason. I wanted to know for myself about the gas mileage. I was driving like a granny, but I think MOST of the problems people have with gas mileage are due to the way they drive it. Some may have engine issues, I dont know.

zerobanger

again, the needle in the car was in the same position. Anytime I have ever "topped" off my rx7 it was ounces of gas before it overflowed. Again, I got 26 MPG the first time, 30 the second. The 2nd time was a lower RPM.

Dont take my word for it, one of you guys should try it.

i3man

I think when you'e filling so few gallons (only 3) you're susceptible to a much larger margin of error than when you're filling 10+ gallons. I don't mean to burst your bubble either but I don't think experiment proved anything.

It's like shooting 2 free throws and making both, then proclaiming yourself a 100% free throw shooter. Now try and shoot a 100 free throws and tell me you made 100 in a row. A larger sample size will always produce more accurate data.

JeRKy 8 Owner

I thinkposts like these that peoplemake about getting high mpg are redudant anduseless. OFCOURSE you guys are going to get great mileage when youdrive 100% highway on atank. Thats the same storyw/all cars. What Im still waitingto see is someone get 18 mpg or more w/100% city mileage. Who caresabout these great tanks you guysget out of highway miles? I didntbuy this Rx8 to drive it all over the freeway did I? Hell no!!If anything Im tryingto show it off in the city. Iappologize for sounding like an assholeif I am but I am tired of seeing these high mpg posts thatare just b/c of highway miles and nothing on the terrible pathetic mpgyou get when you drive in city all thetime like me.

P00Man

thats got nothing to do with it, if he used 3.15 gallons, then he used 3.15 gallons.

3.15 is 3.15 any way you cut it.

i3man

Based on your thinking if I were to coast down hill for 30 miles, fill in 1/2 gallon of gas, and say that I got 60 MPG...you'd agree with that too I assume LOL.

There is actually scientific data that validates the premise behind probability and statistical sampling. You can believe what you want about this little experiment but I think most will agree it proved little if anything at all.

The point is we can always skew the results by testing under the most favorable conditions. Most of us aren't interested in hand-picked results in a "controlled" environement.

zerobanger

You make no sense. I drove my car 89 miles the first time at one RPM and drove my car 95.2 miles the next time at a lower RPM.

It not like I said "Hey Im gonna fill up at 3.15 gallons". 95 miles is MORE than enough freeway miles to make an accurate sample of what the car is capable of interms of Miles per gallon.

Also, I have no idea what you are talking about with a "margine of error". it doesn't matter. I drove the car so many miles, filled it up and got my results. Its a fair test and your theory is flawed.

zerobanger

what do you consider city? If your in stop and go driving constantly, then yes you will get 14 MPG. Most of us do combination city/highway. When I drive to work for example its city/highway 18 miles each way. I get 19 MPG. I'm VERY happy with it.

I take my car and drive it crazy I get 16-17 MPG. I'm still happy with it. I posted this because I have seen many people post that they get 12-14 MPG no matter how they drive the car. Also, I was not aware that others were getting such great gas mileage or i would have not posted this.

i3man

Alright fine. You are MILEAGE KING. Sorry for trying to be a voice of reason. No further responses from me in this thread.

zerobanger

Im not trying to be a dick, but again I did not coast down a hill for 30 minutes and fill it up. If read my post, the first time was mostlly down hill and I got 26 mpg. The second one was 95 miles of up and down, it was more like peaks and valleys with no steep hills or decents.

I only did this to see if the EPA numbers are correct and according to my tests it gets better than the 24 or 25 MPG the epa rated it highway.

8_wannabe

No, you're wrong and I3man is right. Everything is subject to error; the trick is to minimize errors so they are no longer significant. This is a basic premise of statistics, and if you don't know or understand this you should not be trying to do statistics. And yes, MPG is a statistic.

here's why 3.15 is not always 3.15. Did he fill his tank to the EXACT, PRECISE same level it was previously? The answer is no, he probably came close and he may have come close enough not to matter much, but it is never exact.

Let's say the level AFTER filling was 0.2 gal less than before making the run. It's a function of temperature, ground terrain, nozzle configuration, and probably other variables. Let's also say he burned 13 gallons on the run. So the error introduced by the fill level is 0.2/13 or 1.5 percent. Now let's say he made the same 0.2 gal error with a fillup of 3.15 gal. Now the error is 6.4 percent. The error is 4 times more significant with the same 0.2 gal mistake. Now, further add in speedo error which we all know is there, maybe a pump calibration error, and the next thing you know you think you got 26 mpg when you really got 21. Most of the error could be eliminated by running a larger tankful, i.e. running it to almost empty. That is by far the largest variable in the equation.

I agree with I3man, this is too small a data sample to get excited about. Now if a few people replicated it then maybe we're onto something. But it's safe to say between forum participants we've had many thousands of fillups under countless conditions and this is one of the first to report this, on a downhill run. He probably got better-than-average mileage, but without that average wouldn't be average.

kingcar

Don't let if get you down there are a lot of people who get some kind of thrill over correcting people and trying to prove someone wrong and this forum is filled with them.

I do however agree that to have more accurate results you should fill after an empty tank and recalculate.

zerobanger

King..

I have absolutely no doubt that If I drove the entire 230 miles and re-filled up I would not have substained that 30 MPG, because I hit some traffic later. had I kept cruising the entire time It would have been close.

as I mentioned in the beginning of this thread my first fillup was with a full tank when I made it 230 miles and I got 23 MPG. that was going up hill most of the way and hitting some bad traffic. those #'s are identical to my FD's.

Considering my FD gets 25 MPG doing the entire 230 Mile trip back, I would guess the rx8 will be similar ..maybe 26 MPG.

I just did this to demonstrate under semi-optimal conditions what the car is capable of. I hope someone else does this test also.

rx-7~rx-8

I take your word...

Zerobanger how did you break-in your rx-8 ?
How many miles do you have on it ?

zerobanger

well this is my 3rd rotary car so Im used to rotaries, bad gas mileage is no big deal to me, lol.

for the first 700 miles I drove the car from 3000-5500 RPM on the highway and kept varying the rpms. I would not let the car stay at any RPM for more than a minute or so, then I would downshift.

I also did some stop and go. I never did a full throttle launch and never redlined it. I hit 7000 by accident once or twice.

after the 700 miles I slowly broke in 6000 RPM, then 7000 and then 8500 and finally 9500 rpm.

after about 900 miles I pushed the car really hard on a really winding road around me. I redlined the car, kept in the high rpms in the twisy's really pushing it hard.

I have 1528 miles right now.

I bought the car Dec 30 with 24 miles on the odometer.

8_wannabe

king, none of us are getting a thrill trying to prove him wrong. Personally, misuse of statistics just jacks me the wrong way anywhere I see it (and I see it everywhere.) That, plus there is so much rumor, innuendo, and false starts on this forum that someone has to try to put things into perspective. My intention is not to argue with Banger or convince him he's wrong, but there are others less informed that, for lack of a dissenting viewpoint, might read his post and conclude it is gospel. It ain't.

Banger concludes with "I hope someone else does this test also." Come on, dude. Many of us have had our cars for six months. Do you think you are the first to try this? Or that your run was unique in some way? You're not, and it wasn't. While the results you posted aren't impossible, they are exceedingly improbable, there are other explanations vastly more likely considering the hundreds of thousands of fillups that have occured with the '8. This isn't a "me vs you" thing, but if you're putting out one possible side of a story, many readers would benefit from hearing other possible sides. And not accepting as "fact" that which is opinion or slim possibility.

zerobanger

8_wannabe, Please dont call me "Banger". Thanks.

You know what? Screw it. Keep your miserable 14 MPG cause you dont know how to drive it. This is my 3rd rotary powered car, its nothing new to me.

I'm getting canzoomers mod done to my car in about 2-3 weeks. I do plan to take it to the track and do a before and after and post the results, but screw it now. I'm sure my test will be flawed cause its not perfect humidity or something. I dont like the reception I am getting.

I'm fine that some of you dont think its valid. One last time, my point was to prove that the car is capable of the EPA's estimate.

Forget it, I dont care any more.

Doug Green

WHO DRIVES 60?

doccable

Exactly. I know that if I drive a constant 65-70, no matter the vehicle, I'm gonna get good mileage. I've gotten tot he point where I just don't care about the mileage. if I drove the car daily, and had todrive more than 10 miles a day, then I'd worry about it. I know that I'm lucky in that respect to be able to keep my 8 garaged until the weekend, or at least when the weather and road conditions allow.

8_wannabe

No offense intended. I truncate everyone's name here and didn't want to call you Zero. That sounded disrespectful. But as you wish... How about ZB?

RX-GR8

zerobanger cmon calling out 8 _wannabe for calling you Banger? it's part of your userid. if you take offense to that maybe you shouldnt have Banger in your name to begin with. you called kingcar "king" so what goes around comes around. pick your battles. BTW you can call me GR8

zerobanger

what a dumbass you are. I told him not to call me banger and he responded decent to my request. For the 16 year old kids like you that are too stupid to figure it out, "ZeroBanger" means my car has no cylinders.

and yes, "Zero", "ZB", "Zerobanger" is fine with me. And I will not be calling you anything.