CarAndDriver

I did a 109 mile trip. 84 miles was on 4 lane highway at speed averaging about 70MPH. The remainder of the 25 miles was urban driving.

Averaged 22.5MPG on 91 octane. I had a/c off and sunroof wide open the whole time.

In comparison, I did a quarter tank of complete city driving with lots of stop lights and engine on and offs, 3 people in the car and averaged 16MPG.

Q121825

In more than 70,000 miles of driving, mostly highway, I have a combined MPG of 21.1 with my best tank of 23.1 and my worst of 17.8.

Tim Benton

Driving to Fla, 30 miles of city driving and basically the rest where pretty much highway driving - 24.78 mpg. The next tank of gas was 1/2 highway, 1/2 city while in Fla and it was 21.30 mpg. This is in an unmodified 05 auto RX-8.

Tim

CarAndDriver

Just did a 70 mile highway trip with gentle crusing and acceleration. I averaged probably 70-75 the whole time on the highway. I got at least 23.1MPG if not a tiny big higher. A/C was not on.

I think the RX-8 can easily meet the EPA highway estimate considering how easy of a test it is. I'm curious how much my mileage would increase by dropping the speed down to 65MPH or so.

DrDiaboloco

I'm about to do a very long highway stint, over a thousand miles, so I should have three fillups on an all-interstate run... Four if you include the top-off at the other end. Unfortunately the AC will be on the whole time and that will roon it, but maybe the return trip will need less AC... I'll report later.

Hopefully very little of that trip will be at 65mph.

MazdaRich

Yep I'm about to run about 2500 miles in mine. I hope to average about 22mpg, possibly by slowing down to 70 or so.

PhotoMunkey

In LA traffic and cruising up the 101 freeway north to Pismo Beach, I got 21.24 MPG. Coming back down the 101 and through LA, including getting stuck in the I-91 traffic for an hour, I got 21.9 (all the way out to Palm Springs)! The very next tank, cruising across the desert heat, with the A/C (A/C was on for ALL of the other tanks too, BTW) on I got 16.93 mpg, with no change in driving style.

What does this car do when the intake air temperature goes up? Is it pulling timing back? To drop 5 MPG simply because the ambient air temp has gone from 90 to 105 is fairly ridiculous. Fifteen degrees shouldn't make that much of a difference to the engine's systems. On the way over last Sunday to LA, through 109 degree temps, the car recorded 16.7 MPG so this isn't a statistical abberation.

PhotoMunkey

Also, the mileage doesn't seem to change until AFTER the car is shut off and restarted in the desert heat. It's like the computer checks the ambient air temp at start up, then assumes that's where the setting remains for the rest of that key-on cycle.

My kingdom for a plug-in, real-time data analyzer!
Eric

cruzdreamer

19mpg city after 35,000 miles on her!

RX8PDX

I havent actually calculated the MPG, I just pay attention to how many miles I fill up at..... And usually its well after the light comes on, the needle practically is on the line. I think when I look at the slip its usually around 13.4-13.7 gallons? That sound right?

I usually get 200 miles to a tank, driving 15min to work, all city and the lights are close.

I had a friend who just had a lung transplant up at Seattle, (hes doing great), so I drive from Portland to Seattle, and get well over 300 miles to the tank.

So I started driving like a sissy, shifting around 3500 or less.... its painful, but i got about 250 to the tank.

Wasnt worth it to me, I enjoy driving like every light is a race to the speed limit :D. That and I love hearing my wife say "Do you have to drive that fast". Why yes honey, I do .

I think one thing to think about too. A lot of people see 1.3L and expect that kind of mileage. But we have 3 combustions per RPM vs a piston. So its more like a 3.9L. Maybe my logic is bad there.

DaGnome

I don't have any fancy spreadsheets able to post atm but figured I'd chime in here as well.

I've a 2005 MT RX8, purchased Feb 05. (White) I live in South Florida and use the car mostly for commuting to/from work (23miles each way). It sees full highway speeds on occasion, about 1x per month.

I've tracked every single fillup since I owned the car (thanks to a nifty Smart-List-To-Go database I wrote for my Palm).

I've now exactly 69 fillups recorded, over the spam of 16.7k miles on the car.
I'd estimate about 85% were from the same Station, and about 90% were complete fillups (over 12 gallons, I'm one of those who relies on the light before I stop).

My average MPG have actually been slowly increasing since day 1... I started at about 17.0 and it's been steadily climbing to now at 18.1mpg. The highest I've ever gotten on a full tank was 20.8, and the lowest was 14.2 (one very odd fillup, average lowest was around 16ish).

Average distance between fillups has been about 230-250 miles. Worst was 191 and best was 271.

Not the greatest gas milage in the world, but then again my previous car ('93 Eagle Talon, only got about 23-24 in the same town). I'd drive this car over my Eagle any day

CarAndDriver

Well some are saying that the new engine flash post recall work is affecting mileage a bit. Itll be interesting to see.

SecrtSqurl

I got the flash a few weeks ago. I thought that it would be worse for gas mileage. But..... I am getting 10 miles per tank more than before the flash. I drive the same route to and from work everyday and have made no side trips.

They did replace 2 of the three plugs (odd?) at the same time. I found this odd since i just had all the plugs replaced 3000 mile ago with the "new plugs", and could not figure out why only 2 would be replaced.

Do you think the plugs wear that fast, and do new plugs make that much of a diference after so few miles?

BunnyGirl

Not that is means anything other than what I observed, a few months after I got my car I had to go in to get the plugs changed since the "new" plugs had been on backorder and so they weren't available when I picked up my car and had to wait for them to come in. They were replaced with the previous type of plugs at time of delivery. Well, the first full tank of gas with the new plugs I got 25.62 mpg with my same route and everything where I usually got an average of 23. Of course, it then promptly settled back down into my average range so I don't know that the plugs caused this to happen. Probably just dumb luck.

CarAndDriver

My mileage seems to have got worse with the recall work. I did 70 miles of highway at 70-75MPH with gentle acceleration and got 20.5MPG. I think I was doing at least 22-23 before.

Wish I was getting better and not worse.

Razz1

I'd like to see one comparing MPG vs RPM.

Range 4 to 5K
Range 5 to 7K

for those drivers that use this range consistently. I just got 10.3 MPG it was in the 6 to 8k range, and alot near 8k.

Funny thing normal driving varies greatly, but I can get 20 plus on the freeway.

zeblien

I have a AT, and I drive in the range of 5k - 7k 75% of my miles. I get 18mpg. I red line it once a day or more.

Raptor75

Well have driven my car painful genitally in the past and got no better then 13mpg city. Driving normally I get 12 to 12.5 mpg. Rotary God said that he could get 18mpg city in any RX-8 by shifting at 3K rpm I disagreed but figured I should give it a try. So for 10 agonizing days I drove 97% of the time below 3k and the results were 13.6 mpg and Mazda still says the car is working fine.

Loved the RX but I hate Mazda and their "who gives a ****" attitude!

zeblien

I belive some cars are cursed with unusualy bad Gas Millage. I agree with Rotary God that any car capable of gettin 18mpg can get that driving in the city. Some cars like yours, cant obtain that so its worthless to try.

I wish the reason that some cars dont get more then 12/13mpg was discovered though.

Raptor75

Here in lies the problem.

It is obvious to all that a select group of RX-8 have a problem that Mazda has chosen to ignore. It is decisions like this that earn them a place at the bottom of all car manufacturer for servicing their vehicles as reported by JC Power. It also costs them in bad PR and lost sales. I myself will slam this car and Mazda in this respect every chance I get to anyone considering a Mazda. I have decided not to get a C7 because of this poor support. I have had a hand in swaying other to choose a different car manufacture after relaying my problem.

What it would cost Mazda to just analysis and fix my car they have lost 10 times over in lost sales that I have been a contributing factor yet they sit in there offices wondering why they are rated so poor and what they can do to correct this. Fix your damn cars, stand behind your product.

Love the RX but MAZDA SUCKS!!!!!

zeblien

Well telling us here doesnt do any good does it? Not buying a C7 doesnt hurt Mazda if they dont know you were going to buy it.

Complain to mazda, not to us.

Raptor75

My friend, you don't know that Mazda monitors this board???

This board not only tells Mazda but it airs their dirty laundry to their client base. I'll share something with you, when your screwing something up as a corporation the last people you want to know this are your potential clients. I can think of few more effective ways of telling Mazda then posting on this board and unlike a letter, once this is posted it can haunt them for years to come.

zeblien

You think complaining about it here for the..... 100th time will change their minds. Im sure a Mazda PR looks at a lot of sites. Why dont you send them a personal letter to let them know you want a serious answer.

Raptor75

Actually I know it can. Zoom 44 once pointed out that several issues raised on this board had a direct effect on Mazda. Your idea of a letter is good if not one dimensional, rest assured that I am pursuing this on several fronts.

zeblien

Your calling my idea one dimensional? Its not an idea its the best way to get anything done. Email is still a very unformal way of communication.