IcemanVKO

I watched an Rx8 review video, and they mentioned that the 6 speed, had less torque than the auto, and they alluded to the fact that it had to do with gearing.

I made a statement on Hymee's thread and was talking about WHP, not Engine HP, but after thinking about it, Dyno runs are done without gear changes, and you aren't moving the mass of the car, but instead a fixed mass, so gearing really shouldn't affect torque numbers on a Dyno.


I do think I read that the reason for the reduced HP, in the auto was due to the auto not being able to handle the high revs, at the same power level that the manual would.

So someone tell me why they put more torque in the Auto, than the Manual? Cause I have confused myself.

therm8

It's all in the tuning. The 6-port is tuned for high rpm power, and in general you have to sacrifice a little lower down to get it up high. The auto, not needing to make power above 7500rpm can be tuned for a little more lower end power. 'Low' being a relative term. I'm not certain but I think intake runner lengths has a lot to do with the difference.

IcemanVKO

So noone really knows how much Torque either transmission can handle.

We do however know that the Auto cannot handle the RPM's that the Manual can.

I would think, that the Auto would handle more torque, just because of the liquid nature of the auto. The Manual transfers the Torque to the gear teeth, and clutch.

Anyone else lose a transmission yet, other than the Petit Turbo one?

mr2000x

This isn't entirely true.

Nobody can say why mazda made the decision it did, but the original version of the auto had the same rpm as the manual. When the car went into production that had changed.

you can read my comments here about why i think some trannys in the auto's are different from others:-

https://www.rx8club.com/series-i-specific-performance-mods-97/rx8-4at-owners-only-46710/

JeRKy 8 Owner

See rotarygod posts like this one

https://www.rx8club.com/series-i-specific-performance-mods-97/heres-why-engine-has-less-power-potential-than-6mt-20148/

Do a search on his name for more

rotarygod

Damn I wrote alot in that thread!

The 4 port engines make MORE power than the 6 port engines up to about 7000 rpm. It's hard to notice this though since the auto transmission sucks up alot of power. The 6 port engines are only mor powerful from 7000- 9500 rpm.

IcemanVKO

Man after reading all that It sure seems like it takes alot of work to get HP gains out of this engine.

Icemastr

I believe it is not because the automatic transmission cannot handle the HP in the higher RPM's it is because the potential reliability problems of a street car with an automatic transmission running to 9000RPMs.

zoom44

not true! I can emphatically state why mazda made the decision it did. The reason there is no auto on the Hi-power engine is because the auto tranny available to them in time for production was unable to handle the 9k rpm of the hi-power. it was simply destroying the auto trannies in testing. since they did not have the time or money in the budget to engineer or source another auto tranny the decison was made to only offer it in the standard/low power renesis. they are however continuing to research and test alternatives for future years including a SMG type tranny.

mr2000x

And that's that.

I stand corrected! :p

IcemanVKO

I swear stuff like this should simply be added to the Faq. I read so many different opinions, when we find that something is a fact, lets add it to the Faq.

mr2000x

But where are the facts??

The only true fact is this:-

Nobody really knows but the Mazda engineers!