CERAMICSEAL

Don't mean to sound rude but we need to keep fuel economy scientific. Set your trip meters at the point of filling up (To 0) and at whatever point you next fill up check how much fuel you are able to put in (To fill to the same point), check what distance has been covered and do the divsion. Amount of miles divided by amount of gallons as an example provides miles per gallon.
As an important side note: Always fill only to the point that the pump clicks off. DO NOT OVERFILL THE SYSTEM.
It's obvious that our rotary engines are thirsty, but let's not make it seem worse than it actually is to our piston powered cousins or to those who are considering purchasing this fine car.

klegg

There is something wrong with your car. Call MNA, see what they can do.

LoveMy8

Well I have owned my 8 for about 3 months now. No complaints whatsoever. Anyway, I know the car is known to get crappy gas mileage, but for some strange reason, the last time i filled up I got 230 miles to the tank, alot of mixed city/highway driving. Before then I was only able to get like 200-205. Well when I got 230 I drove the car alot harder, chirping 2nd alot and just driving harder. I usually fill up as soon as the light comes on, so it is not like I filled up later than usual this time. Im going to continue to drive hard and see if the numbers stay consistent. I will let everyone know.

conedodger

I got real decent mileage for my very first tank full. After that, I was only averaging around 14 mpg. Don't know what happened between first and subsequent tank full's but I'm hoping my mileage goes up when I get my car out in April. I only have 1500 miles on my baby so maybe things will be better as the engine loosens up. I drive fairly aggressively too. Love to hear that engine rev!

markd

Interesting. I don't know that it makes any sense that aggressive driving = better gas mileage, but you never know. Keep in mind, too, that your gas mileage will improve the further out you get from your break-in period, so that might have something to do with it.

On a related note, I know it's been said here that you should shift around 3500 rpm if you want to save gas, but is there a point on the lower rpm range where it becomes counterproductive to shift as early as possible? I mean, sometimes I shift at 2500-3000 rpm thinking my gas mileage will improve even more, but it seems to be worse. What's the absolute lowest rpm at which I should shift (I also have a/t, not sure if that makes any difference) and still see beneficial gains in fuel consumption?

markd

bump

BlueFrenzy

I did an experiment for this tank of fuel. I usually shift at 3500-4000 and cruise at around 3500. I decided to go grandpa styles and shift at 3000 and cruise below 3000 (very similar to the shift points that Mazda recommended in the manual). I found that I got an additional 50km (~31miles) out of the tank. It was really boring though.

Nick Alvarado

Hey boconnor....good luck with your ride. I have had mine since Nov. It was a Mazda showcar, loaded with 3,200 company miles. I have had some issues with oil seals etc. but am holding my own cause I love the car. As far as you gas milage concern let me tell you...I average around 14 miles per gal and now have around 4,700 on it. So as you can see milage has not really improved much from your car. What I have been able to pick up from our fellow RX8'rs is that there is sucha a thing a Flash card update for the computer gas settings. As a matter of fact Mazda sent out service instructions for cars to be updated if they were manufactured before such and such a date.(you will have to look this up) One of the RX8 members posted it recently. Now the catch is that some drivers have had good luck while other say they use more gas. Your call....now as far as optimal for myself, I will be glad if I can get an average 19 city and hwy. Keep in touch

NgoRX8

iTrader: (1)

I as well have had bad luck with the 8's gas mileage. Sadly, I drive an automatic. But with that besides the point, here are my figures:

using 91 octane

mileage total----mpg---------Manual shift
1748-------------13.28-------------No
1908-------------12.57-------------Yes
1988-------------12.66-------------Yes
2159-------------15.07-------------Yes
2348-------------15.48-------------No
2402-------------13.25-------------Yes
2559-------------14.48-------------No
2717-------------13.18-------------No

Also, I drive about up a hill about 10-20 times a tank, which is about 6-12 miles of revving up it. I usually shift it or get it to autoshift at 3-3.5k rpms.

It is sad to watch my fuel needle move down so fast, probably wont get over 200 miles on the tank.

Experiment: Basically on this tank I am manual shifting at about 4k. According to the needle it seems to be about 10-11 mpg, but we all know how accurate that is. I will provide my data after my next fill. I want to find the cost of mileage for having some fun.

How much of a gain in mileage would a lower octane provide?

Cynik

Hello, this is my first post to this forum, new reg user etc.

I have recently purchased a 2007 A/T RX8 (52K Miles), doesn't appear to have the DSC or TPMS or the cool stuff you know? But it is a lot of fun to drive. I previously owned a '79 RX7 for about 6 years, so I have some of the basic knowledge of owning and maintaining a rotary engine, but I wonder if there are a few things I may not know about this generation of the Renesis engines that may relate to my MPG problem.

I have filled about 3 times since I bought the vehicle, first tank I pulled about 15mpg, second tank I pulled around 12mpg, and the third I average about 14mpg. I have been reading about all these owners that routinely acheive 17-18 or even 19 mpg, driving hard and/or driving granny style. (I realize that some of these are M/Ts which would naturally get better mileage than an A/T)

I have tried to use the M to control shift points, I have driven in fully auto mode, stomped the gas, rode it like a tricycle for one tank, and I haven't seen anything make any difference in my MPG. I also premix 2-3 oz of 2 cycle oil with every fill, as I always did with the 7.

I have been reading these forums for a week now, and have learned much about this topic, (great site!). One thing in particular I read was that a drop in MPG can be the first symptoms of fouled plugs or possible a clogged cat? As I was not the owner of this car until two weeks ago, I have no idea what happened during the break-in period, or if the plugs are originals, or what.

Can I get some opinions on whether or not anyone thinks this may be happening to my car? Again, there is no way to tell if it was getting better mpg before recently, so I know without that info it is difficult to tell.

I live in Orlando, FL, which is basically flat, so elevation isn't really a factor. Are these numbers common for other AT owners (2007 model)?

Any help would be greatly appreciated. I love my car, but I certainly believe it can do better than 12-13 mpg. Thoughts?


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I have seen some other users that also get 12-15 mpg so this may just be normal. Still would appreciate any thoughts.