LesPaul

I tried a search and didn't find anything on this particular point.

I travel on roads that have a long streach of 45 mph.

Is is better to stay in second gear at about 6,000 rpms or go to third at around 4,400 rpm?

I've read the engine 'loves to rev', that gas consumption may be better at high revs and that the rotary behaves differently than conventional engines. Any thoughts would be appreciated.

oosik

personally......i keep the rpm's around 3k when just cruising with little to no other traffic. with other vehicles around I run it a little higher in the powerband just for E&E......

LL7

I drive mine in 3rd or 4th at 45. I tried it in 6th for a while to save gas, but it didn't seem to do anything but make the car feel like an old Tercel if you stepped on the gas. I think 3500 to 4500 is a good cruising speed.

druck

According to the analysis of the US engine maps, its running rich under 3600 and over 6200, and lean between 3600 and 6200. So the bottom end of that range would be best for crusing.

Cheers
---Dave

Winning_BlueRX8

when cruising i usuall shift at around 4000 rpm

f1michel

You mean it burns more fuel at 3k then 3600? I just find this hard to believe...

Goldenhue22

Me as well. I I want to conserve gas I would think the lowest RPM's...the better. Therefore cruising in 6th even at 30--35 mph would save more fuel than 2nd gear at 5K RPM @ 35mph. But would love explaination.

RobDickinson

it runs lean mid rane, but that doesnt mean it burns less fuel at higher RPM.

Lower RPM will always burn less fuel I bet.

f1michel

I just don't get why it runs rich under 3600, makes no sense to me.

druck

See the tread in the Tech Garage Official word from Mazda on dyno'ing RX-8 interesting stuff starts at page 9

Cheers
---Dave

Reeko

Rich at low RPMs and lean at higher does not mean that it burns less gas at higher RPM. It only means that there is too much or too little fuel being injected at a particular RPM.
Also, remember that that Air/Fuel Ratio that was measured was probably at Wide Open Throttle (where the ECU goes to Open Loop Mode, relying on maps instead of measuring the exhaust).

ptiemann

Agreed.. look in your RX-8 manual, I think on page 5-9 it has the shift points - really early. E.g. 21 mph shift into 3rd.

That's how to get those 24 mpg (not that I'd do it)

I personally keep it around 3500-4000, depending on the steepness of the road.

-Peter

ptiemann

Thanks Dave - this link to that thread was GREAT. I think it's the best thread I've read on the board so far.

Everyone should read it!

pelucidor

For maximum fuel economy the manual suggests the following shift points:

1st : 0-14mph
2nd: 14-21mph
3rd : 21-28mph
4th : 38-35mph
5th : 35-42mph
6th : 42-145mph

Having tried these out once (I stopped at 115 in 6th) I find that the book means one has to change up to the next gear at around 2800rpm, which then drops your revs to 2000rpm. That is if your aim is fuel economy...

However anyone who drives like this all the time would of course be missing the point of the car and should have got a Toyota Prius instead. Personally I tend to accelerate hard (8k-9k) and then go to 6th around 45-60mph.

LesPaul

Thanks Druck. Don't know how I missed that thread. Hope canzoomer puts his work on the market soon.

druck

Well its hard going for the first 8 pages with lots of people arguing over Mazdas statement and various conspiracy theories. But then canzoomer comes in, he's done the research and he really knows what he's talking about.

Cheers
---Dave