Best rpm to cruise at for mpg?
 

So, although it might seem logical to drive in the highest gear possible, some times it's not the case, as you are at such a low rpm you are bogging the engine down.

Now I'm just doing an experiment on how good the gas millage of the rx8 can be.

So...

I've read the manual, which if you look under normal acceleration has you shifting at around 3000-3200 rpm, and for coasting, 3000 rpm from 1st-4th gear and under that for 5th to 6th.

Reading on the forums states keep it under 3750 so the first set of valves don't open.

So I try to shift around 3200-3500 rpm.

But would riding the highest gear possible be the best for this car? I know in my old car for whatever reason, depending on the speed, if you kept it under 2000 rpm for coasting, you got slightly worse mpg than if you kept it just above 2000 rpm (might of been my imagination, who knows)

Just trying to confirm here.

Thanks

I think there are two answers. For getting the best mpg, yes, I suspect the highest gear possible is best, assuming you're not bogging down the engine.

But many believe the rotary needs to be revved to be healthy, otherwise it risks excessive carbon buildup. Me? I generally drive like you, for better mileage—but I temper that by running to redline a couple of times a day, and also driving in the upper (4K-7K) rpm range a little every day, too.

Forget MPGs, all I know is in 6th gear 3700 rpm is 72mph, which is a good speed to avoid tickets on a 65mph interstate (i.e. all the ones round here). If I run up around 4500, that's cop-magnet speed!

Shouldn't cruise any lower than around 2.4k. Like you said, you don't want to bog the engine. The rotary needs to be revved as well, you don't want carbon build-up. When it comes to shifting for gas mileage, shifting before 3750 is pretty much the only thing you can do, however, it's still a sports car, so stretching its legs every once in a while is a must.

As an alternative, try learning some ecodriving techniques if you're new to the subject.
http://en.wikipedia.org/wiki/Ecodriving

i've found 3000rpm to be the 'sweet spot' for this engine

I always thought the sweet spot was around 8000+...

3000rpm for loafing around, i should add...

"When accelerating, the engine should be kept in the peak of the torque curve, this is usually at around 75% throttle Citation needed. A slow acceleration is less efficient. "

can anoyne cite that on the wikipedia page? i'd love for that to be true. lol.

stoplight gran prix? yes please.

Well I hit redline...a lot :)

I'm just comparing how much gas I'd save with sane driving vs redline every traffic light :p

According to the owners manual:
Recommendations for Shifting
Upshifting

Normal Acceleration
1 to 2: 23 kph/14mph
2 to 3: 35kph/22mph
3 to 4: 47kph/29mph
4 to 5: 58kph/36mph
5 to 6: 74kph/46mph


For Cruising
1 to 2: 23kph/14mph
2 to 3: 34kph/21mph
3 to 4: 45kph/28mph
4 to 5: 56kph/35mph
5 to 6: 68kph/42mph

So I'm assuming as long as we're in the mid range of the cruising speeds we should be okay...?

i think i shift into 4th at 40mph, 5th at 50mph, and 6th at 60mph. dunno about the lower gears.

I chatted up a guy at a gas stop and this is how he drives. He says he gets more than 21mpg in New York City. His technique is to keeps RPMS below 3k. I was thinking... 'Why'd you get this car?'

I put approximate RPMs next to your table.

Normal Acceleration
1 to 2: 23 kph/14mph (3150)
2 to 3: 35kph/22mph (2950)
3 to 4: 47kph/29mph (2850)
4 to 5: 58kph/36mph (2550)
5 to 6: 74kph/46mph (2750)

For Cruising
1 to 2: 23kph/14mph (3150)
2 to 3: 34kph/21mph (2850)
3 to 4: 45kph/28mph (2750)
4 to 5: 56kph/35mph (2450)
5 to 6: 68kph/42mph (2500)

My typical shift points:

1st to 2nd: 9000
2nd to 3rd: 9000
3rd to 4th: 9000
4th to 5th: 9000
5th to 6th: 5000

:)

Accelerating I use about 1/2 throttle and shift at about 7k when I reach cruising speed I go to 6th unless I' going up hill, then I like to keep it at about 4k up the mountain 4.5k cruising. I get 20-23.5 mpg usually over 22mpg, lower in the winter though. I use 87 octane Shell. 35k on 2004 that I bought new. Down hill I coast except down the mountain 3rd gear to hold speed.

I'm with you stew - lol

I have a A/T and these are the MPG I got at different speeds.
At 55-60mph I got 29.5mpg
60-65mph I got 27.5mpg
65-70mph I got 24.5mpg
These were all done with more then half a tank of gas. Its very hard to stay in the slow lane for 200+ miles with the big trucks at just over 2000rpm on your tach. It takes patience too do this twice to verify your results, but I was curious what this my seventh Rotary would do at best. At 3000 RPM my speedo says 73mph, but I believe its really approx 70mph. Normal driving city 16-18mpg hwy 20-23mpg, it all depends on my right foot. My first rotary RX-2(in 71) got 12-city 20-hwy with half the HP.

How did you calculate your mpg at different speeds? Separate tanks and doing all your cruising at that speed?

me too stew...but thats well over 100mph....3rd to 4th is about 96mph...and i cant remember what 4th to 5th is at the fun 9,000rpm...still haven't had the opportunity to experience how much fun 4th to 5th or 5th to 6th...soon though

I drove more then half a tank at each speed range twice to verify. All hwy, Lots of patience. See what yours will do. Many times I would start to do my mpg test and a situation would arise that I would get out of the zone and start going too FAST....you know what I mean, the car is just asking for a reaming out.

Ok, gotcha. I thought for a second you were using a scanguage or something like that to calculate it, but you're doing it the most accurate method. On a long round trip with my recently installed K&N, I got 26 mpg, with a normal cruise at 75 mph. This was probably 98% hwy, though. I normally get 21-23 mpg in mixed driving.

9200 Rpm

If you're even half serious, that's pretty impressive!

Last week I finally had the balls (and the room) to redline 4th. Before that, about 6 or 7 times total I managed to only hit the warning buzzer in the same gear.

Edited away my comments. never know who is lookin'

i cruise at the lowest rpm (usually about 2-3k) as long as i'm on flat ground. up hill usually requires atleast 4k or the engine will be boggin. basically...if you bought the rx8 for gas mileage, you're stupid. go buy a civic! people always ask me..."you get good gas mileage?" and i laugh...i bought it to drive it...not to save at the pump. my whip has this addiction to get as close to tha red as i'll let her...who buys a sports car for gas mileage! get unleaded at arco if you're worried about it...lol....either way...i love my car...she's my mistress...

I found that anywhere in the 110-117km/h range give about 460km per tank, and 120-125km/h give about 440ish and anything over that i only got 410km for a tank

so for me the ideal range was probably 3200-3400 rpm in 6th.