Jesus1199

I busted wanted to know what are other people mpg. my is 12mpg and sometimes 9mpg. Does anyone know how to improve the mpg. I know by nature the 8 drinks a whole lot gas but I heard of people have 15+.

thanks for any responses

TheWyvern

~13 City, ~22 Highway. Some say premixing helps with mpg. I've not really noticed a huge difference.

Chrishoky

iTrader: (9)

I get about 200 - 225 miles per tank, so around 15-16 MPG. The health of your engine contributes a lot to MPG. Hows your compression and ignition?

Loki

iTrader: (1)

That's not normal. Like said above, check/replace ignition coils and spark plugs. Drop the catalytic converter and examine it forclogging or breakage. Do this fast, those things will kill your engine.

I get 380-400km from full tank to the the light. 240 miles. 70% highway.

wcs

iTrader: (2)

buy a civic

edit: oh I'm with Loki I get about 400 ish + to a tank

Reoze

I get about the same, if not worse. Compression is 7.5-7.6 all the way around. No Cat. I always assumed it was just a side effect of my lead foot.

yurcivicsux

400km ish out of boost
300km spirited driving in boost

UnknownJinX

My Fuelly Page

Only 3 tanks so far, 15~16 MPG with fairly spirited driving(redline yeah!), mostly city driving. I use Idemitsu Premix as well.

9 MPG is not normal unless you are at a track. Check your ignition, blah blah blah... You should know by just reading some of the stickies.

To be fair, my V6 Accord is getting better mileage, but the handling difference is enough to offset the gas mileage difference, not to mention the 9000RPM redline of the RX-8.

Reoze

This is the second RX8 I've owned, and driven identically. With the same gas mileage. Ignition system is working perfectly fine. I'm aware of what some of what causes of low fuel economy are.

But when my AP is telling me an average of 9-11 mpg depending on the day and is calculated solely based on injector load and RPM. I don't think it's a mechanical or electrical problem. The instantaneous fuel usage at WOT is about 2-4 mpg for me. Combine that with craploads of traffic and high RPM driving in between, it's not something that surprises me in the slightest.

This isn't anything exclusive to our cars. If I drive my 35 mpg altima the same way, I'll get 10-12 mpg out of it too.

UnknownJinX

9 MPG just sounds insanely low to me, but I suppose under certain circumstances, it's possible.

I personally tend to keep the RPM between 2.5k and 4k RPM for cruising around. What's your cruising RPM?

One other factor for bad fuel economy I could think of is how some people will religiously wait 5 minutes or so before they start driving their RX-8, which to me sounds a bit ridiculous. I just drive it as soon as the navigation loads up. I do make the point of never revving it past 4k RPM before the variable red lines go away, though. I know for modern piston engines with fuel injection, waiting until it fully warms up is harmful. The only time I wouldn't start driving until minutes later will be because the car is covered in snow and I need to wait until all the fog goes away.

Reoze

That's the thing, I'm rarely ever "cruising" with the road conditions around here. I'm either stuck in stopped in traffic, weaving in and out of it, or trying to get ahead of it. The only time the roads are clear around here is after 9PM. I'd say my average (moving) highway RPM is somewhere between 5.5-7.5k. Another way to put it, more often than not I'm in 3rd/4th gear on the highway.

I'm fully aware of what I'm doing though and I'm definitely not complaining. If I did then I'd have to be a flaming idiot. I could care less about the extra $40/week I probably spend in gas. I'm just saying that it's absolutely not out of the question for these cars to guzzle gas like that without a mechanical problem.

As far as not waiting for the car to warm up, that's debatable. I'm fairly certain the fuel economy is significantly worse while the engine is cold. I'll usually let the thing warm up a good way before driving. If I'm in a rush I'll let it tick the needle on the gauge. If I'm late for work, I'll end up doing what you do though.

40w8

I put a scan guage II on my 07 6speed auto, and was averaging about 8 to 10 mpg on a H2R track at San Marco, Tx.

You're full throttle up to about 90 mph, brake hard, and coast corners at around 30 to 40 mph.

By around 20k miles I was only getting 5mpg and some misfires.

I put in the BHR ign kit and fuel pump, and started getting better than new mpg: aprrox 10mpg average of 20 minutes on track.

At 10 years old and 34k miles I was driving 120 miles at 75mph, and averaged 26 mpg on a 60 deg day with no AC. No wind or maybe a little behind me.

This is pretty much best scenario of mpg on a healthy RX8.

UnknownJinX

Makes sense then, it's just kinda unfortunate that you have to go through that kind of traffic. Then again, I personally don't drive my RX-8 much for school since I live so close to school; I typically take my RX-8 out for a rip at night when there is no traffic around. Of course, there are also times where I have to suffer through traffic, but just not very often.

As for the warming up the car thing, remember, you get 0 MPG when you are idling. And like I said, idling for a long period of time when the engine is cold can lead to bad carbon buildup on fuel-injected piston engines. I'd love to see the effect of cold idling on a rotary engine. I just take it easy when it's cold, as I know it takes a while for the heat to distribute evenly around the entire rotary housing. On my S2, it doesn't take long for the 5k redline to go away, but the 7k one can take a little while.

wannawankel

There is a BIG differenc ein MPG for driving ~ 70-100% city and 0-10% city driving. Mine is 13-15 in the city and 18-21 on the highway.

Jesus1199

I got about 68,000miles on the engine. I gutted the catalytic converter so its free of any clogged. I changed sparks and ignition back on when It was on 66800. However the ignition coils were pretty cheap one from amazon. Spark plugs were ngk. IM thinking its probably the AFR sensor.

Jesus1199

before my mpg was 12 but dropped back to 9. One time is dropped to 7mpg guessing it from the AC. I live in NYC so traffic is pretty bad depending where I am heading to. I just wanted to know how I could I improve this mpg. Im guessing probably the cheap ignition coils I put on. I bought a son adapter recently not yet installed. But Im guessing to probably the AFR sensor?

Plus I gutted my cat I don't think that will have any affect on fuel economy.

I premix my gas well just started to. How do you guys premix your gas?

Reoze

Step 1. Pump Gas
Step 2. Pour oil into cup
Step 3. Pour cup into gas tank

If you're asking about which oils at which ratios to use. There's a giant 176 page thread on it, and a smaller one that was started up a few weeks ago.

Chrishoky

iTrader: (9)

I do the opposite to allow the premix to better mix with the gas.

1. Pour premix into gas tank
2. Pump Gas

Reoze

I started doing it this way. Then ran into the unfortunate incident where I didn't transfer money onto my debit card and went to the pump. Only ended up with 3-4 gallons but 13 worth of two cycle in there to throw off the ratio pretty significantly. After that I started doing half first, half after, but it was just too much of a pain in the ***.

Loki

iTrader: (1)

That's pretty unlikely, O2 sensors don't read lean when they fail. They read inconsistent and your computer can detect and tell you that. Diagnose, don't guess. Get an OBD2 scanner and reading the sensor data your engine is seeing.

Jesus1199

The scanner won't throw any codes....filled the tank today now I have 13mpg. I'm guessing is the way I drive at times. Depending on traffic and short trips.

speedieone

I bought my 2010 R3 last fall with 25k miles on it. My mpg has ranged from a low of 13 to a high of 23. The 13 was right after I got the car and involved a lot of high speed runs. The 23 was on a recent trip back from DGRR. During the DGRR trip I averaged 21 to 23 during highway driving with most of the driving being done in the rain. Around town normal driving I'm averaging about 17 mpg.

Squeegee

desert racing I got 5