6MT Horsepower Question
 

How much horsepower is generated by the 6MT stock RX-8 rotary engine at ***7500*** RPM? Tried searching for this answer on RX8club and Google, but could not find an answer.


EXILE

232 SAE rated Horsepower at 8500rpms.

I know :P For some reason I had the redline of the automatic in my head. :P

I want to know what it is at **7500** RPM on the **6MT**...is there any way to calculate it or is there a graph of a horsepower/rpm curve?


EXILE

212 SAE is what the 6port engine is rated at for the 6AT @ 7500rpm.

edit, had it right the first time.

212
-R.

That's my redline.. ;)
I think I can go past that on paddle shifts though..

I was looking at the 2006 spec sheet for the RX-8 and I noticed something curious. Both AT & MT have the same 6 port renesis engine now, but the MT redlines at 9000 RPM while the AT redlines at 7500 RPM. But the maximum torque is listed as the same -> 159 at 5500 RPM. I assume that the the difference between the two redlines is because of the AT torque converter. Conversely I was wondering if the 6MT had the same horsepower at 7500 RPM which is the redline for the AT. If so, I find that to be interesting and noteworthy.


EXILE

They're tuned differently.

If they have the same torque at the same rpm, then the HP is the same. Straight physics: power is torque times rotational speed.

Makes me wonder if the engines are now the same, other than the converter-mandated red line. Dyno plots will be interesting to see.

Ken

Check the sticky on dyno graphs.

Also many are not listed there. Also do a search on dyno's

Thank you all for the info. I will search the dynos. I think the RX-8 is a truly spectacular car.


EXILE

Something doesn't make sense.

If the suto and the manual have the same engine, same torque, same weight, both have 6 speeds, same ports, and both have the same hp at the same rpm's with the exception that the auto only goes to 7500 (making 212) and the manual goes to 232 at 9000 rpm, wouldn't they both run about the same times in 0-60 and 1/4 mile? But they don't, not even close, which would mean that they are tuned differently, making it possibly that the 6mt actually is getting it's hp/torque down faster then the auto.

So, just because the auto is making 212 at 7500 rpm, it would seem the 6mt is making more then 212 at the same rpm... of course, I may be totally wrong, which brings up the point, why is the 6mt faster in the short run?

The gearing on the auto vs manual used to be vastly different. I don't know much about the new 6 port automatic, but assuming that remains true, it wouldn't effect the hp numbers since they're rating it at the crank.

I don't find it surprising at all. I think there are 2 main factors at play:

1) Auto tranny robs power.
2) 1500RPMs of high power is not there.

And possibly, like the other poster said:

3) Gearing may be different to compensate for the narrower powerband.

With a 130hp engine, my 2003 Protege made 90whp with an auto, while a manual version made 100whp. That's a 30% vs a 23% driveline loss.

1500 RPMs of high power is quite a big difference. Also, this means that with the same gearing as 6MT, you'd be landing at lower RPMs after shifting.

You are out of luck because the only dynos you'll find on here chart power to the wheels. I doubt you'll be able to find an answer to this question.

I guess I don't feel so bad for not finding the answer after searching :)
No problem, I like both cars for what they are. In the end they are both great rotary powered cars depending on ones needs and tastes. I have enjoyed the discussion in this thread.


EXILE

the 2 6 ports are the same. Port timing, intake, everything. Peak torque says that tuning is the same. The 4 port made more torque at peak due to tuning and port timing. The 6 port engine therefore makes 212 SAE hp at 7500rpm. No question, that's your answer. Dynos won't tell you much because rated hp may not be exactly correct, no one actually knows the drivetrain loss, and dynos depend on many factors and aren't all that comparable from car to car and day to day. So 212hp is the rated hp at 7500rpm. That's probably as good a number as you'll ever find without engine dyno'ing it yourself.