rx8montreal

is the rev limiter really is at 9k on the rx8? because i can rev mine up to 9400k and i have not flash the ecu.....

Flashwing

The rev limiter is set to 9,000 RPMs on the stock tune however as you climb higher in the RPM band the tachometer is more inaccurate. It's already about 200 rpms off in the lower parts of the RPM band.

The PCM reads the actual RPM amount and will limit you at 9,000 RPMS regardless of what your dash instruments tell you.

ARE-EX-8

SO basically if im reading 9500 .... im actually doing 9000. HMM interesting

nycgps

iTrader: (1)

At stock tune, power after 8500 rpm is dropping so fast that there is no point revving further.

The engine itself can handle MUCH higher RPM, its just that if you're not making power, wtf is the point? you're just wasting gas.

So they limit it at 9000 rpm.

You might ask why not limit it at 8500 then? well, 9000 looks better than 8500 rpm thats for sure. and the power level between 9000 and 8500 is about 5 hp. so

Nubo

An additional consideration is: where in the powerband will you be after you shift? While there might not be much power to be gained after 8500, shifting later will get you further into the power once you upshift.

PhillipM

^^Which is why we have a 9.5krpm limit on ours

kersh4w

iTrader: (3)

you can rev yours up to 9400k? that is amazing.

i've never seen an engine run at 9,400,000 rpms before. how much horsepower do you have? you must have the elusive mazdaspeed8.

CyberPitz

I jumped into this thread expecting this post every time...then you're the only one!

kersh4w

iTrader: (3)

i cant stand it when people do that.

nycgps

iTrader: (1)

damn, I missed that part

Im sure his Rx-8 can do 3 minutes or less at Nuburgring

tubingchamp

iTrader: (3)

Yeah, I was just going to reply with 9,000,000 rev limit is HUGE, what kind of mods did you have to do? Only the ram-air intake can allow such high RPMS..

rx8montreal

http://www.youtube.com/watch?v=NhpbhxBEU-E

i think that now we can see what i meant when i said 9300-9400rpm cut-off!!!!
stock ecu

Snrub

If 9000 RPM is represented as 9400rpm on the tach due to error, shouldn't the error be something like 9000 +/- 4.4%? Alternatively it could be something like 9000 +/- 4.4% +200. Both are standard ways of expressing measurement/instrumentation error. I've never heard of a RX-8 with a fuel cut reading under 9k. Logically it doesn't make a lot of sense to calibrate the tack with an additional fudge factor to ensure it's always above 9k (that doesn't mean it isn't the case). Thoughts?

I don't think it's fair to say that the engine can handle much higher revs, at least not on a sustained basis. As Nubo said, it makes sense to rev beyond peak power to maintain the maximum amount of power under the HP curve (average engine output).

ShottsCruisers

Reving an engine like that (even a rotary) without any load on it is plain dumb. You're asking for troubles.

tubingchamp

iTrader: (3)

See his answer?? He's going to get a 20b......

HAHAH!

Anyways, atleast it's not cold.

MazdaManiac

iTrader: (3)

Don't forget, at 9,000,000 RPM, the rotors are only doing 3,000,000 RPM.

ZumnRx8

sounds nice & get that CEL cleared!

MazdaManiac

iTrader: (3)

He's running a Jet "V-Chip". No control over the CEL.
Looks like he's gonna switch to an Int-X, so I don't think he cares about the CEL.

ZumnRx8

^ thanks im googlin it, never heard of it for our cars..

Flashwing

The rotary, by design, is capable of handling much higher revolutions. The primary limiting factor is the harmonic frequency of the apex seals which is probably around the 13,000 to 14,000 RPM range.

The secondary (and more important) limiting factors are the transmission and the airflow. The transmission isn't designed for those excessive RPMs and the engine's VE falls above 9,000 RPMs which is why there's a power drop off.

It's hard to say why there is a % error with the tach. It's not off by 400 rpms as it's more like 200 to 250 rpms but the error gets worse the higher you are in the RPM band. When I hit my 9500 RPM fuel cut my tach reads nearly 10,000 RPMs.

In my case I wanted a high rev ceiling to keep me in the power band but also to avoid hitting fuel cutoff. Various other vehicles pull timing at redline while the RX8 pulls fuel. The last thing I need is a freakish lean condition with the motor spinning that fast under full load and KABOOM. Only side effect I've found is having to run very rich above 9,000 rpms. I'm in mid to upper 11's otherwise the car gets really upset.

Snrub

^ Correct me if I'm wrong, but I thought chatter marks and bearing wear start to become a concern with sustained use even in the 9-10k range? I thought even the Grand Am cars (Koni and GT) run lower RPMs than realistically possible to ensure longevity. I believe the R26B in the 787B was detuned significantly detuned as well as it's race day peak power was @6500rpm.