Gosh, I just don't see how it's possible to hit 12.5mpg...anyway, here is my data:

19.x mpg my first fill up, not sure how you got 12.5 but where you in heavy traffic and keeping the revs over 3.75K alot???

But yes...this is a dead horse topic...

 

There are 3 ways to get bad mileage:

Drive hard
Stop and Go
Short distances

at least from what I can tell.

 

OK, a little background on my driving and me. I'm 44, married with 2 kids so the RX-8 was a nice fit for the family. I'm IT Director for my corporation and have a degree in Mathematic & Computer Science with a minor in mech. engineering. (Calculating gas mileage is not that taxing for me). I have a long love for sports cars and a strong knowledge of automobile engineering. I have rebuilt 4 engines in my time and am highly mechanically inclined. I have always loved the rotary because of its uniqueness.

Driving style. Once the car is broken in I'll be driving it hard about 20% of the time.
Presently, let me requote from my original post: “I am driving it gentle the first 600 miles, keeping revs down, no racing , ect.....Weather has been around 40 and my driving is suburban/city.”

The car is a 6 speed Grand Touring, Black. I’ve replaced the stock tires with 245/40/18 ultra performance all season tires, Avons.

I am convinced that there is something causing the wide discrepancy in mileage. I have seen people report good mileage while driving very hard and seen other report 10 to 13 driving like an old lady. The personal driving style cop out doesn’t cut it for me. I have been driving like an old lady and got 12mpg. As I have acknowledged it is only the first tank so this number is hardly conclusive.

Justifying a sub standard performing car with excuses like” it will only cost X dollars more per year” or “it is a sports car so don’t worry the excess $” just doesn’t cut it for me. I want the performance level I paid for.

 

I don't see either unless there is a problem. Now if you were getting 12.5 mpg would this be a dead horse issue for you?

 

Did you calculate out how many miles were driven on the tank versus what you got a fill up, knowing if you had a full tank to start with, or did you divide however many miles on there it said by how big your tank was? I am just asking because I know so many people who do it the last way. I would say to wait for your second tank and calculate out that way since with the first tank it's hard to tell if everything was set right on the trip and everything.

 

Raptor75:

It is IMPOSSIBLE to get a true picture of the MPG without doing the following:

1. Record the mileage at the initial fillup.

2. Fill the car personally to the very top.

3. Drive until Empty Light on.

4. Record mileage.

5. Again fill it up again to the max. Record gallons.

6. Go back to 3 at least twice.

7. Finally do the math - Total distance from first fillup divided by Total gallons. Remember NOT to add in first fillup.

Unless you have done this - the MPG you are reporting is useless IMHO. a single calculation will not cut it.

As for comparing drivers - it is very difficult. My opinion about how I drive is totally subjective.

Finally my point about annual / monthly cost is that the RX-8 is a sportscar - ENJOY it.

You state " I want the performance level I paid for." but have stated nothing about the PERFORMANCE of the car - just the mileage. You paid less than 35K (Basically the max I think) - for a exceptional sports car which is ESTIMATED to get 15 to 21 mpg

Again my 2 cents

 

13.5 - 13.9

And a tank is from FULL to the light coming on. I wouldn't call it a tank filling up with 1/4 left...

We all have the same size tank and the light comes on about the same time also.

 

My first 05 I broke in around Atlanta traffic. I figured I get bad mileage considering the traffic situation. Surprisingly, I got 17 MPG on my first tank with 100% city driving < 4K RPM (mostly).

My second 05, I broke in on a long highway drive from KC. 100% highway varying my speed between 55 and 70 the entire way (mostly). Got 22 MPG.

I'll say this. I can get real close to the posted 18/24 but its pretty dull driving. I figure my poor mileage at times, is 80% my right foot weight and 20% rotary inefficiency. I cant blame the car.

12.5 is low but I agree with most. Keep track for the next couple of tankfuls and try not to vary your driving style too much and see what you get. Also, try different gasolines. I get the worst mileage using Chevron. Premium recommended.

If it doesnt get better, take it back to the dealer to verify the latest flash is installed. Good luck.

 

I believe the empty light comes up when 2.8 gallons are remaining in the tank. Can anyone verify? Also, what is the tank capacity again, 15 or 16 or?

 

NgoRX8:

Beautifully put - it is almost impossible to compare mpg for different driver - each with their own view of their driving style and manner.

Most driver consider themselves better drivers than they are - and that includes yours truly. Stop and go traffic is a killer - and I note the original poster in in Chicago. Once flew into Chicago on Thanksgiving eve - took two and 1/2 hours to travel from the airport to the I-80 - normally 20 minutes. Boy was my MPG poor that trip.

Sports cars (driven either as sports cars or as commuters) get poor and very variable mileage. My wife's CRV on the other hand ......

Nothing personal about the original poster but RX-8 and MPG are not spelt the same - PERIOD. But FUN/Unique and RX-8 are.

I'm not an engineer BUT it would seem that if an RX-8 was getting very poor mpg due to improper fuel injection etc. there would be true performance issues - Perhaps someone more technical could advise.

 

Raptor75:

Are you getting performance issues with the car? Stalling / exhaust smell/ poor idling /poor acceleration - etc to suggest major drivetrain or fuel injection problem.

 

380km on first tank then got 430km from full to empty without refueling, last twenty km after fuel warning light comes on. Please SEARCH

 

Man...

Some of you are "search" snobs...

The "search" function does work (and usually works well), but this guy is asking something else other than another plain vanilla mileage question -- he wants to know if something is wrong with his car... I mean 12.5 MPG on the first tank is pretty bad... I agree that he should wait a while to see how things settle out...

BUT some of y'all need to chill out, take a breather, or just simply "get some" from your significant other...

REALLY...

You're going to pop a aneurysm...

 

No the car runs great, looks great and dose put a smile on my face. In hindsight I do need to wait a few more tanks fulls as many suggest. But I just heard from a few of you who were getting good mileage out of the gate.

BTW, an overly rich mixture could cause poor mileage with out noticeable performance issues.

 

Raptor75:

Enjoy that car - it sure is a trip to see that 9000 revs and the engine just going.

Still think the variable MPGs reported are generally due to variable driving and driving situations - not some other issue.

But do track it for a few tankfuls - and if less than 17 or so - get it checked for sure.

 

I don't think anybody remembers what their mpg was on their first tankful on the top of their heads. I didn't even care until I started trolling on this forum and saw people whining.


The gas mileage is directly related on how hard you mash the pedal and not only the shift points. Sometimes I get better mileage shifting at 5k than I do at 3.5k. I can practically tell my mpg on each tank: 16-19mpg mostly city sprited driving. I've seen a thread here where all these geeks brought out their excel spreadsheets from day 1. Don't worry and enjoy it for now.

 

Sooner or later, you're going to have to face the fact that the 8 does not get very good gas mileage. That's just the way it is. The RX-8 MPG has been hacked and trashed to death on many forums and the final analysis is always the same; the RX-8's MPG is less than the cars it seems to compete with. You need to weigh this fact against the attributes of the 8 (which are numerous) and decide if its worth it for you. Compared to some of the competition, you may (probably) have paid less for the 8, and that should be factored into your overall cost of owning and operating the vehicle.

1.3L

 

If your gas gauge is like mine, the dealer could have shorted you 2-3 gallons and it still would have registered full. That would have definitely impacted the mpg calculations. Like others have said, give it a few tanks. Hopefully you will see it rise.

I get 18-19 with 95% city driving.

 

You know if you use the search button you'll see plenty of threads of people asking the same question, with similar mpg avgs!

 

I recall reading a 15.7 gallon tank.

 

actually that's 71 mph in 6th gear. (Remember our speedometers are 2 mph faster than we really are).

As for the main thread... your mileage is very bad for a first tank. The RX-8 gets bad mileage, yes, but not that bad. From what I've observed from this forum, a majority of people get about 15mpg city, 21mpg freeway with an average of around 18mpg mixed driving. That's pretty much what I get now. There are some people who can't seem to get under 18mpg, even driving somewhat aggressively and 100% city. And there are some people who can't get better than 12mpg, even granny driving 100% freeway. Those people are definitely not in the majority though from what I've been seeing.

When I first got my 8, my first tank of gas (as in I drove it till near empty and then filled, divided miles driven by gallons put in) netted me 15 mpg... mixed. I changed my driving habits a bit since then and now I get about 18mpg mixed.

The tank size is 15.9 gallons and the light comes on around 13.5 gallons used I think.

btw here's my improving gas mileage tips thread. maybe it'll help a bit?

 

Well you asked about 1st tank mpg. I picked my car up from the dealer on 1/28/06 and filled up on 2/3/06. The guage registered full at the dealer as they topped it off. I got 267 miles on 13.48 gallons that's 19.8 mpg. I estimating 30% city and 70% highway on that tank. I did see some of the upper rpm range on this tank but not for long.

And yes I'm loving the car. I had a 2002 vette that I traded in a year ago and interestingly I averaged 22 mpg on the daily work drive I'm doing with the RX-8. But then again that car managed 31 mpg on the highway on cruise at 78mph. The 8 compares to Vette in handling, is a little softer overall but, of course, doesn't hold a candle in torque and top speed. But then again it doesn't cost 50k either!

 

The 1st tank should be disregarded until your 3rd. Dealers will put cheap gas in the car, vs. quality. This is an assumption, but it could explain your bad mileage. My experiences with different gases was an eye opener. Never realized that it was such a HUGE difference..basically, stopped by a cheap gas station (Space Age - I think), filled it up, drove no more than 4 miles, and the sucker sucked 1/4 tank!!! WTF??? So, from that point on, if I have to drive the extra miles, I'll get mine from Shell/Chevron/76..all the other wanna-be can drop off the planet...

My 2 cents worth..so..try that out and get back to us on how well it works/not work...hope this helps!!

 

My mom's last five cars going back to sometime in the 80's have all been Mazda. The dealers in our area (at least the various different ones we have been to) have recommend using Chevron as the preferred "best" gas as it is supposed to be cleaner with that "Techron" they add to it (includes Texaco with Techron now also). Second choice has been Shell with V-Power on what is recommended. When we are back in Wisconsin visiting relatives the Clark station always seemed to have great gas that gave great mileage. I don't what gas company they are through.

 

Haven't tried Chevron on a tank-basis. Been mainly Shell and getting 17mpg during my city travels. During my highway trips, getting 22-23mpg...but, Bunnygirl, you got me curious on whether Chevron is "better" than Shell. Will have to test them out for a couple of tankfuls to compare...