Raptor75

Enjoying my new RX-8 quit a bit but I just got slapped with the MPG issue. My 1st tank full produced 12.5 MPG. I could watch the fuel gauge move as I drove. I am driving it gentle the 600 miles, keeping revs down no racing , ect.....Weather has been around 40 and my driving is suburban/city.

I was not expecting anything great 15 to 17 was my target but 12.5 is horrendous. Here is my question. How many of you experienced poor MPG that got better with time? If so how long did it take? What did you get at the start and now what are you getting?

Spin9k

Not being a wiseguy - but yours is the 1,000,000 post concerning mileage on this board! You can search and find 100's of threads to read and help/confuse yourself on this topic, easily.

Some advice - I don't think you can trust 1 tank fillup as the correct mileage... wait a few tanks for a better reading - make sure you calculate correctly from one gas slips gal amount (not tank capacity) to the next ..plus.. using your trip meter as the correct mileage. Sorry if this insults your native intelligence, but it isn't how some calculate... and then MPG is wrong.

Last cold weather/city driving/short trips is the worst for the car. That's just fact.

Enjoy your new ride and give it some time before you pass final judgement. Cheers!

Flop

There are MANY threads on this subject.

Personally, I regularly get only 190-210 miles on a fillup of gas. This is with premium gas, and driving it city and some highway. When I go all highway, I can get 330-350 miles on a tank. My driving style is calm (70%), agressive (30%) in the city.

toca

its a sports car if u wanted gas milage get a civic hybrid

RotaryNoob

First tank got me 220 miles. After that I couldn't get past 180 on a tank until the latest flash. I now have 22K on her and with the latest flash I get about 220 a tank again.

Raptor75

Please no stupid replies like this. The 350Z, S200, Z4 are all sports cars and all get at least 33% better gas mileage then a normal RX-8. I expected that but the numbers I report are well below that average. So please CONSTRUCTIVE contributions here.

Based on several posts this MPG seems below average but as SPIN9k has pointed out, it is only the 1st tank. Then again the 2nd tank is not looking any better.

I would like to hear what other users have obtained new and if it has gotten better. I have read many of the past posts on the MPG issue but I'm targeting a specific time frame here.

I know this is beating a dead horse to many on this list but I want to understand why this is happening. The car is being feed to much fuel, why? If it gets better with time, why? Could there be a defective sensor in the fuel delivery system? Is the compression in my car worse then a car that gets 17mpg city?

There are a lot of posts about the poor MPG but very few that try to address why that is. The rotary is basically an inefficient engine this is physics not much we can do about it. Much of the energy is lost to heat in a rotary. But why do we have large discrepancies between similar cars, assuming similar driving styles and conditions. If drivder X can get 17MPG why can't I?

I'm looking for information form those who know the car and the engine well.

Thanks in advance.

Rumboo

^^^ He's got a point. I mean, 12.5?! That's way below your typical 8 mileage.

Hope it gets better for you, Raptor.

Raptor75

Thanks, how many gallons do you put in at fill up.

rabinabo

The mileage should improve, but it's not going to something you notice from one tankful to another, but over thousands of miles. Also keep in mind when you compare our mpg numbers to others that you NOT use the EPA estimates, since they are not representative of the mileage that is actually achieved with the way most people drive. If you look around at cars of the same class (like the G35) you'll see they get about the same mileage.

IZoomZoomI

i'm getting advertise mileage no problems here. You can't expect much on stoplight to stoplight traffic. Checked your tire pressure? If your shifting past 3750 rpms thats the main culprit thats when the secondary injectors kick in.

Roaddemon

12.5 is way too low unless your driving short distance in 0* weather or driving The **** out of it to redline. Tell your dealer and keep any eye on the next few tank fulls. Could just be the gas or the car breaking in. Should get up to 18 in the city normal driving. I do.

Raptor75

Understood, I compair long term test drives mpg reports from trade mags when I speak about milage.

Kevin

Mugatu

iTrader: (1)

if you want something constructive, you should try typing "gas mileage" in the search field and enjoy the plethora of existing threads on the subject JUST LIKE YOURS.

AirlockRX

I concur with your statement, couldn't have said it better.

Gord96BRG

Says who? If you've followed long-term tests in Car and Driver, Road & Track, Edmunds, etc, you'd have seen that the 350Z (for example) mileage IS nearly identical to the RX-8.

Not to be rude, but you're already being told "Please, no stupid questions like this". It's patently ridiculous to base a whole thread about poor mileage on the first tank - assuming (lots of those assumptions around, eh?) that you actually mean the FIRST tank, as in the tank was "full" when you drove off the lot, until your first fill-up. How do you know that tank was actually full to start with? For gods sake, run a few tanks through at least before you worry! (To your credit, at least you are talking MPG, and not the pathetic "miles per tank" that some people who can't figure out the math post here!)

Despite your claim, there ARE dozens, if not hundreds, of threads discussing WHY the RX-8 doesn't get great mileage, differences in city stop-go vs. just low speed vs. highway, initial vs. post-break-in mileage, and so on.

The car isn't being fed too much fuel. You likely don't have a defective sensor or poor compression. Driving styles vary. However - your engine is brand new. It does need to break in. Stop'n'go traffic gives significantly worse mileage than steady speed driving - idling is where the rotary inefficiency hits worst.

So, my advice is: Give it a few hundred miles, get it broken in. Drive it hard, don't be afraid to rev it to redline! Get a few tanks under different conditions, calculate the proper mileage (I will completely ignore stupid posts talking about miles per tank), and read more mileage threads, go waaaay back in the forum history. Amongst all the nonsense, you'll find maybe 5% of the posts are from people who understand the issue and make well-considered points.

Last point - stop over reacting! It's the first tank on a brand new car! Enjoy the car.

PIGBAIT

My first tank of fuel took me 150 miles. I bought the car new in November and now I'm averaging about 190 miles on a tank....I reset the trip odometer with every fill up and it hasn't broken the 200 barrier yet, although I've come close with 198.9. But that was with the gas needle pegged on E. Don't worry your mileage will improve.

Raptor75

Road & Track's long-term test drive has the 350Z averaging 20 while the RX was around 16. My mistake, it is only 25% better. The Z-4 and S-2000 are even better. Come on, lets call a brown shoe a brown shoe. RX-8 mileage is a weak point. Every review, article and most postings on this board confirm this. The only real question left is how one RX differs from another and what should be considered abnormal.

As to your other points I have to agree with you. One tank is hardly an indicator, although it was a full tank so the mpg is accurate. I've been reading through the past posts and have been monitoring them for some time. I'm curious if the newer cars were doing any better. I may have started this tread prematurely but I have read about enough users in a similar situation that I figured I'd start collecting info.

I agree on the miles per tank issue, mpg is a definable measure.

I'll be logging all mileage and we'll see how it goes but their is so much conflicting view and reports out there with so many variable not being defined that I am attempting to narrow the variable to get a more accurate picture.

If you have time I have posted a poll for mileage but requested only 6MT doing 100% city respond to it. Again trying to gathered data that will mean something.

I consider your post constructive because you bring up valid points. Thanks for contributing.

BunnyGirl

I copied this is from the printout I got for my 2006 RX-8 that I am still waiting to arrive.

CITY MPG: 18
HIGHWAY MPG: 24

Actual mileage will vary with options, driving conditions, driving habits, and vehicle's condition. Results reported to EPA indicate that the majority of vehicles with these estimates will achieve between 15-21 MPG in the city and between 20-28 MPG on the highway.


So, if your car gets between 15-28 MPG you are fine and is what is expected from the car.

BunnyGirl

What is up with everyone talking "I got x miles in a tank." Doesn't anyone know how to actually figure out miles per gallon??!! Getting x miles in a tank is just fuzzy math at best. It does not take into account how much gas was actually used versus how much was left over, et cetera. Someone could get gas everytime they get around half a tank or around one-quarter of a tank and still call it a tank of gas!!!!

Please people, if you are going to debate your MPG at least learn how to calculate it!!! You may find that you are getting higher than what you think you have.

Here is how you do this:

Take the number of miles driven (on a tank starting from 0 until the point where you get more gas). Then divide that by the number of gallons you get at fill up. This will give you the answer. This is like second or third grade math!!!! It's really easy.

EXAMPLE:
Drove 250 miles on a tank.
Got 12.5 gallons on fill-up.

250 / 12.5 = 20.

You got 20 miles per gallon.

See how easy that is? Next time somebody posts about their mileage actually bother to calculate the MPG instead of the per tank crap!!!

NgoRX8

iTrader: (1)

^lol BunnyGirl got mad.

I get 19 mpg all highway. I guess I could get better mileage if I stayed below 3750, but thats like 73 mph in 6th gear. It's horrible!

Rupes

It sounds like this will be an ongoing problem if one of your first posts is about how bad the gas mileage is. Personally I don’t think getting another 5 MPG, which will save me what, $10 a week, is worth worrying about. The car cost me $30k, why worry about a few dollars in gas? I think most of us have come to this conclusion, and if they haven't, they've bought other cars.

I also had no idea what kind of mileage I got on my first tank because I was busy enjoying the car. Hell I don’t think I started paying attention until I drove across the country several months after owning the car. Your statement about getting only 12.5 MPG is very rare, however, and you should expect the posted 15-20 city MPG to apply as time goes on.

This car doesn’t get good gas mileage unfortunately. Sorry.

rabinabo

Yeah, the miles per tank can vary enormously with every person. I mean, do they drive till the low gas light comes on or do they refill at 1/4 tank, etc. It makes a big difference.

BunnyGirl

At least at my house general rule of thumb is that if the light comes on you can put at least 20 more miles on. My mom's MPV can safely do about 35 more miles. She had a Protege that could get around 50 more. Never tried pushing any of these vehicles past this point. My mom's MPV gets around 21-22 MPG and the Protege she had regularly got 36 MPG and once got 42 MPG on a cross country trip.

My friend in Virginia has a yellow RX-8 6-Speed and she averages approximately 19-21 in city driving and around 23-26 on highway driving. She fills up after her light comes on, usually about 25 miles after the light has come on and stayed consistently lit. I know in my mom's cars they sometimes light up and then go out. I think it probably depends on the angle of the car thinking there is less gas than there is.

Spin9k

Raptor75, you bought the car already doing research and knowing these mileage facts and falacies about the 8's mileage ...why? ...and now you want us to explain it to you? ... being an IT guy you argueably are more analytical than that and know what you're getting into. I don't get why you're a bit defensive about answers you get... you know here in the forum we've been through this with hundreds of stories like yours. You must appreciate where many of the comments are coming from....frustration w/new owners frustrations mainly lol!

You could help your knowledge quest if you gave us (who have come before) and you (who want to learn from us) a tad bit more personal info... auto or manual? detailed driving style? .i.e., .. what gears do you favor and drive in at what speeds? e.g., some never use 6th... some drive in town in 2nd or 3rd only ... some correctly shift up whenever the load and traffic allow. Are you using premium or 87 octane? What's was the weather like? And has been metioned several time... do you figure your mileage as suggested... fillup to fillup using mile driven/gallons? These are things that affect all our mileage, but we don't know much about yours. Of course waiting to post these after a 1000 mile or so would be best when you're more in-tune w/the car.

(off soapbox) Please take the above as, for what it's worth, constructive criticism.


My personal theory, (and that's all it is, a theory, not proven or quantified) concerning 95% of the poor mileage sagas in this forum, is this: "The only real question left is how one RX DRIVER differs from another and what should be considered abnormal as it affects mileage".

Myself I drive to 8-9000 rpm whenever possible in whatever approriate gear, traffic permitting, then shift up to the highest gear possible after that and drive peacefully. City mpg is 16-18, highway is 19-22, mix is often 18. Roughly the same mileage as my 1992 2.3L Eagle Summit wagon (rest its soul) and roughly the same mileage as my 2003 PT Cruiser Turbo. But a hella lot more fun So don't worry just enjoy the ride, isn't it worth the few pennies per tank entra even if it is higher than you'd like?

Another way you might choose to look at it is this: Calculate whatever extra cost you anticipate for gas over any of the competing makes you are comparing the 8 to. Got that number? OK...so how many hours do you need to work to cover that? Perhaps 5..10..20..30 at most depending on your salary... doesn't seem to important does it...rather just enjoy the ride like we all do.

RX8_GT

Personally I get about 18 to 20 MPG in all my RXs - including my 18 year old RX7s. It's about 60% highway - 40% town.

But given that the difference between the RX-8 at 16 mpg and a 350Z at 20 mpg based on 12000 miles per year, is a total of 135 extra gallons or about $320/year ($26.50/month), I'll drive the stylish, fun to drive and responsive RX-8 rather than the box with an engine 350Z anyday - period.

This is RX8Club.com ....not the Prius Club of America or the Any Sporty Car Club .

My 2 cents on the RX-8 mpg issue.

PS Chill on the mpg issue - $26.50 per month extra is a deal IMHO.