Big disscusion on the 7 board about an 8 tranny in a 1st gen 7. It would be great to have the 6 speed, but there seems to be some disagreement whether or not the 8's tranny is strong enough. Anybody have any comments? Quite a few people seem to have HEARD that there is problems with this transmision. Any help would be appreciated.

 

There is much talk that it is not as strong as the ones in the FC Turbo or FD. But to be specific as to how much power it can handle, I can't answer that. As compared to a transmission in an SA/FB, I would think the RX-8's is strong than those. But I may be off on that also.

 

I can't truly say the RX-8's transmission is weak, but I will say it may have a hard time handling power compared to the R-series transmissions (TII, FD). If you want a 6-speed, invest in a bulletproof JZA80 Supra transmission. I hear they can handle insane amounts of power. Look at all the 800+ rwhp MKIV's.

As a side note, Charles Hill managed to install a 50+ shot nitrous system on his RX-8. So far, his transmission has held up quite well. Perhaps there is some strength in this gearbox.

 

A first gen RX-7 would have quite a bit less weight though wouldn't it? That would mean less stress on the transmission. If it's not enough though, I'd go with this:

http://www.jericoperformance.com/4.html

 

Haha. Jerico. Don't forget about G-Force.

 

My tranny is bathing in Redline MT90, and my clutch is now operating via the MS stainless steel cable - all I can say is what a difference. This tranny is strong, it just needs a taller 6th.

 

Why a taller 6th?

 

A "taller" gear, meaning that the rate of increase in engine speed vs vehicle velocity is higher than a "shorter" gear. The result is that the taller gear will pull harder, but will reach maximum engine RPM at a lower output shaft (wheel) RPM than a shorter gear. Neither is better or worse, taller gears accelerate better, shorter gears give you a better top end speed. I don't want to cruise at 145, I want to get there fast.

 

...anyways.

don't forget that the 13B-MSP is about twice as strong as even the best running 12A.

 

I don't have a 12a in mine. It is a GSL-SE, 13b 6 port. I must say that even with it streetported and a header with a straight pipe I don't think it will make enough power to where the tranny will break. At least in my way of thinking. I may be wrong though. Any thoughts?

 

The 13B-MSP has twice the HP, but not twice the TQ and thats what hurts transmissions. More like 1.5x the TQ at best?

 

Yes but mine is not a 13B-MSP. Torque is 130lbs ft 135 hp. After the build it would be more like 180 lbs ft and 210 hp est.