What kind of driving are you doing?
What oil are you using?
Are your plugs and coils old?
These all atribute to gas mileage.

FYI, I get 14-15 consistently, I do very little highway driving at all.

 

oh alright thanks for the feedback from everyone, I have about an 11 mile commute to school and back, if I go the speedlimit of 45 I can make every stoplight in green. and after school I have a 4 mile commute to work which is pretty close, I am using 5W-20 regular motor oil. The cars relevently new, a 2007 so I don't believe the coils or plugs can be that old either, my dad picked up the car begginning of january 08 brand new, and the way it has been driven hasn't changed. I was before getting 17-18, and going about 240 miles per fill up, on my last fill up my car said I only drove 177.6 miles :/

 

your using the synthetic oil that is recommended with the car? hmmmmm

 

wow, I'm retarded, sorry. I'm using 5W-20 regular motor oil

 

That still seems low...even for our cars. Since you are under warranty, take it over to the dealer and have your plugs and coils checked out. Best first step.

 

Better question than how old are they, how many miles are on the odometer?
How cold does it get where you live? Do you warm up the engine before you drive or do you just start it and go? I think it may have something to do with all the short trips your making. Not 100% sure though.

 

I'm 20. I have 13k on the odometer, I live in Arizona, It's ridiculously hot here. I warm up my engine. and I've been driving the same route for atleast a year and a half.

I know about rotarys, I had an 88 rx7 when I was 16. Lasted me nicely til some punk totaled it, so I know a good handful about them

 

Right on, have you changed/cleaned your air filter recently. Could be dirty? I'm really not sure. May want to check the plugs and coils for good measure. Have you had it into the dealer recently, they have a new reflash that could help. may be worth a shot if all else fails your still under warranty.

 

Do you mean you turn the engine on and let it sit running a few minutes before you drive it?

 

yupp

 

This is a little off-topic, but I would worry about using 5w-20 oil in Arizona, no matter what the manual says (not trying to start another oil war, just bringing it up, search and there's lots of info on this).

 

oh wow, I'm kind of curious about this. Why should I not?

 

That is part of your problem. You are using quite a bit of gas idling, combined with a fairly short trip.

 

It doesn't take my car any longer then 2-3 minutes to warm up, and from that break in between school and work my car is already nicely warmed up, and after my work shifts my car is already 1/2 warmed which takes half the time. and on days I'm in a hurry I just drive it out of my garage and let it warm up on the way there.

 

I think 14mpg is very realistic ***if** it's purely city driving with short trips. If you are trying to say that 14mpg is an average of city AND highway driving then something is defintely wrong. If you drive your Rx8 calmly for first few minutes, there's no need to warm it up beforehand, just wait until it's warm before you hit the redline ceiling. This is particularly if you live in a warmer environment. If it makes you feel any better I used to get close to 14mpg in city driving when I owned an Rx8. The fact that the worst I now get is 22mpg, average 28mpg and best of 39mpg in my MX5 NC is another story.........

 

Is this about the same MPG you got on your "88 rx7"?

 

Couldn't tell. haha, the car didn't have a trip meter. But I have buddies rx-8s with strictly city driving who are getting their 17-18 mpg

 

here is the recommended oil weights from the Aussie Manual



i probably would sport 20w50 most of the time in southern AZ from Havesu across through Phoenix etc maybe a 10w30 in Flagstaff

 

My last few fill ups I have only got 12.5 MPG

 

Releasing the parking brake helps quite a lot. This also improves 0 to 60 time tremendously.

Every time an MPG thread comes up, it reminds me of an age-old story about one of the first Volkswagen Beetles to show up in the US. The proud new owner constantly bragged to his neighbors about the fantastic gas mileage he was getting with his shiny new VW. Finally, one of his very annoyed neighbors started adding a little bit of gas to the VW's tank every week. The owner was estatic at the MPG. Then the neighbor upped the ante by adding even more gas each week. Now the VW owner is out of his mind and brags incessantly about the fantastic MPG.

Then one day, the neighbor starts syphoning a little gas out of the VW's tank each week. For some reason, all the bragging stopped.

-1.3L

 

I ALWAYS do short trips in my 8. I take it out for the occasional drive now and then, but my week consists of driving to and from work, maybe to the store afterwards. I do NOT let my car warm up, and I do redline it at least once a day. I usually sport 15-16 MPG avg. Why not try NOT warming it up fully before leaving, just for the 10 seconds like the manual states, and drive it around on that just for one or two tanks. See if your mileage has changed at all.

 

I do Mixed Hiway and City driving and get 18-21 MPG...

 

yup, seems most are consistent

20+ pure highway
16-19 mostly city
sub 15 mpg pure city AND SHORT TRIPS

if i drive 100% city, stop and go, i will STILL get mid to upper teens, but for whatever reason the short trips (turning car on, drive 2 miles, turn off...back on, drive 1 mile, off...etc) is really what puts me sub 15 mpg. once i realized that, i changed my habits; i will idle my car (ie drive thru bank instead of go in, etc) or combine trips and i haven't gotten sub 15 in a long time. the short trips is what really kills it, not necessarily just the "city" driving...

 

I was thinking of upgrading my '04 to an '09 r3, but frankly it is the mpg that is holding up my decision. I don't know if I can handle 15-20 mpg anymore. Hopefully they figure things out with the 16x because this kind of mileage is no longer acceptable. I wouldn't be surprised if the gas guzzler tax would be slapped on the car if there is no improvement. I know I was looking at GTOs before I got my 8 and there was a gas guzzler tax on that vehicle and if I remember correctly the sticker mpg on that was damn close to the 8.

 

Short trips and low mpg is less costly compared with long trips and high mpg. You can have one or the other. I choose short trips and low mpg.

2 miles at 14 mpg vs. 15 miles at 19 mpg for example.

With a little common sense and mathematics, anyone can see that low mpg is the way to go.

It is really not about looking at your trip meter at the fillup, and seeing whether you broke 180 mi or 200 mi or 210 mi. That's just a sham.

It's really about how many days you last before you must fillup. For example, 180 miles per tank but filling up every 9 days vs 210 miles per tank but filling up every 3 days.

Once you see through these fake numbers, and once we factor in all our circumstances, the entire rx8 community will realize that all our engines are identical in gas consumption
in each scenario. Then we can stop worrying if there's anything wrong with our engines. I know what 19 mpg is, and I know how long you must commute to reach that,
and I know how often you have to fillup if you're getting 19 mpg.

Don't let all these "mpg" lie to you. This is rx8. There is no mpg.