Takashi 7

I got my 8 in January.

My tank before last I got 18.2 MPG. I had about 600 miles on the car.
I just put gas in it again today. This time I got 20.8 MPG and I'm at about 820 miles on the car.

I drive the car normally just as I've always driven a car and I'm doing about 40/60 city/hwy.

PhineasFellOff

Finished the first tank with the "L" reflash today (Saturday). I got 23.3 mpg! This is 80/20 freeway/city averaging around 68 mph in LA/Orange County with some freeway traffic jams. Believe it or not, I even had the AC running the first 50 miles.

Note that I accidentally put in 89 octane for the very first time and I wonder how much of the high mileage was due to the lower octane.

Anyway, I'm back on 91 octane and about ready to take a trip that should get at least 16 tanks of data.

rx8rookie

23?

Yay! That's more like it! 20 would be good too!

Painless

I am averaging about 18 mpg while driving like an old lady as well. I am soon to try a three part fuel mielage increase test. First is an air filter, second is a tornado, and thrird is an exhaust system. Does anyone know why rotary engines specifically are so bad on gas? My friend has a Miata and said the same thing about his.

MEGAREDS

My favorite response to this question: "the thermodynamic inefficiencies of igniting an oblong volume," per this thread. Don't know if it's true, but you gotta love it!

Anubis Rising

Stupid rookie question, but whats confusing me about the Renesis
from the FD is they do claim that you get more mileage than the
old one.. but I have driven the 2nd gen, and had a constant 28/30
mpg.. also, looks like there is hope for our renesis, as some of our
members cars put some mileage, mpg is rising! With the flash, things are looking up! but I was wondering, since I was never
blessed with the 3rd gen, did that car have to have premium gas? some have experimented with the lower octane, but curious why Mazda went that route?

KrustyKlown

Yeah, my Miata wasn't afraid to drink some gas. For me this was caused by two things. I drove that little thing like I stole it (90% of the time) and the thing only had a 9 gallon tank. Even 9 gallons on that little 4 banger doesn't go far when you drive it fast. If I drove it gently it wasn't bad. IIRC I think it was better than the 8 but I am not complaining. In a perfect world I would still have my Miata sitting next to the 8.

One day....Miata Turbo and RX8....together.. I can see it now, the Miata, tireless and pregnant popping out little 3's.... Maybe Grant Wood could rise up from grave and repaint his classic American Gothic with the RX8 transformer holding a socket wrench with the Miata at it's side. Man it is late....what a tangent.

sferrett

The 3rd-gen does require premium gas because of it being turbocharged. (all 3rd-gen rx7's were turbo'd)

The 2nd-gen non-turbo specified 87 gas, I don't know for sure but I would expect the Turbo-II 2nd-gen called for premium again due to the forced induction.

Simon.

Anubis Rising

Thanks Sferret. I did drive the non turbo one.

bobclevenger

reset

ByeByeSaturn

lol megareds you b*$%h, quit makin fun of me (j/k)

I'll try to clarify

A combustion chamber like that found in the rotary is worse than the usual piston engine combustion chamber because:
1) it has a higher SurfaceArea:Volume ratio, so the amount of heat that is radiated away as opposed to being converted into work is greater.
2) when the spark ignites , the flame has to travel a greater distance to combust all of the fuel, leaving some unburnt fuel by the time the exhaust stroke is reached. That is why there are two spark plugs - to reduce this inefficieny. With Renesis, the side exhaust ports allow them to be placed closer to the intake ports, thereby allowing combustion stroke to last longer than with the old peripheral exhaust port rotaries. This reduces the amount of unburnt fuel (I think) Also the compression ratio is greater than previous rotaries, which helps as well.

I should add that this is only why IN THEORY the Renesis should be more efficient than previous rotaries. We all know however that it isn't exactly miserly with fuel. Keep in mind though that it is the most powerful normally aspirated rotary yet built, and more power has to come from somewhere, so.......



How's that - and I didn't even use the words oblong or thermodynamic, even though those words are precious to me, as they are the first ones I learned as an infant.

misterdc

I get 10.6 MPG with my automatic and varied driving in the city (no rush hour/bumper to bumper). I'd say that's a problem. Dealership says it might get better, but, "hey, rotary engines never have good gas mileage".

I am livid.

sjt

The best I've managed to get in my auto 8 is 17.46mpg but that's in a little over 2000 miles of driving so I'll withhold judgment til I break 5000 miles since other have reported that their mileage improved after that point... so we'll see....

I'm just getting kinda sad & poor at throwing down $30 every 3 or 4 days... man... CA gas prices blow donkey nads.

KrustyKlown

I have just over 750 miles on my 8. I am at half a tank and I have traveled 125 miles of 40%/60% cty/hwy driving. This is MUCH better than it has been. I live in Atlanta and the weather has been warm. I also do not have the "L" flash or any mods at all.

Oh and I "got up on it" several times. So I am not keeping it below 4k rpm all the time. 5-6k is average. But I have hit 9k a few times during this tank. :D

Right now I am pretty happy at the way things are going.

One other thing to note. My oil light came on right before I filled it up this time. I was at BP and it was at 2AM so I had to make do with what I could and it was 5W-30 Castrol. I topped it off with a little less than 1/2 a quart. Not sure if that has made any difference. I doubt it but I thought I would put that out there if anyone is taking notes.

Psylence

You can definitely get the stated mileage if you are willing to drive @ 55 on the highway...

But why did you buy an A/T misterdc if mileage is of paramount importance? You know that the added drag of a torque converter on any car does terrible things to gas mileage...

boarder

Slow down... I don't think someone complaining about ~10MPG should be chided about a torque converter. They have only a minor effect on gas mileage, and it does not corrolate to 10MPG from a base of 18-24. Now if he sets his car in Nuetral and revs like crazy for 20 minutes, then you can (and should) yell at him to your hearts content.

I have a manual, I am not happy with the mileage either, though I can live with it.

misterdc

I believe the sticker on my car said 18 city (15 to 21 range.) I can live with 14! But 10? Just because I don't need to be speed racer doesn't mean I don't deserve a fun car with reasonable gas mileage.

Roaddemon

Your beating a dead horse with a stick. The epa mpg is tested according to EPA standards. 18 city and 24 highway. Your milage will depend on your driving habits and conditions of driving. Unless of course you have a mechanical problem. Thats why you have a warranty and dealer. You dummies don't have a chance. Leave it alone already.

Rotary Nut

Nothing to report other than the friggin' price of gas! I also had to add 3/4 quart of oil.

Kagero

I thought I would try to see what I could get gas mileage wise if I took it real easy. Well I was surprised! I was real careful filling it all the way up real slow at the end three times. 27.5! Best ever, boy it was hard to keep it at 65mph. It was on 87 gas useing the cruz. This is an automatic. Most of the time I enjoy it more and get about 20 or 21 on the hwy.

beachdog

After 4 tanks of 89 octane (93 was my norm) and keeping the highway speed below 72 in 6th and getting consistantly mid 19mpg's, I decided I was tired of every car on the road driving faster than me. Last tank I ran through the gears consistantly hard, most shifts between 5-7.5k and highway speeds back up to 80 with frequent runs of 90+. Also hit a lot of bumper to bumper and long red lights. Last tank ? 21.1mpg!

I haven't had any work done but the miles are up to around 2500 now. Could this be the break-in/loosening up?

On a totally unrelated note, Mazda paid for my last fill up and will be comping my oil change next week. My title paper work was delayed in processing and I called the dealer to inquire. No big deal. They acknowledged it was their fault and offered the freebies as an apology. Hope my dealing with the service dept next week for the oil change and airbag recall go as smoothly.

ByeByeSaturn

Could it be the leaner fuel mixtures at the higher RPMs, or just the fact that the low RPMS are excessively rich?

Or could it be that in 6th gear you were actually putting more load on the engine due to the combination of less engine torque and less wheel torque, and therefore your throttle was actually open a fair amount?

I know this topic has been gone over a million times, but stories like yours make this a continuing source of intrigue.

Rotary Nut

Mpg is getting marginaly better. Maybe 5000 miles on the clock is a magic number!

JERCS

i'm at 15k and mpg is only getting better and better.

KrustyKlown

I knew it!!! Another reason I love my rotor motor...