i would like to know if a rx-8 tanny is any good, and if its strong, whats the advantages and disadvantages compared to a T2 tranny. Also if a Tremec t56 is a good swap to do?

 

You should specify what car you're talking about. Your profile says '91, so I'll go with that. I'm guessing NA?

The RX-8 trans is much shorter than a FC trans, and will not fit without cutting part of the transmission tunnel out or moving the motor back in the engine bay.

I'm not familiar with a T-56, but you would need to know if it has the same bolt pattern and if it is the right length.

If your car is NA, you can swap in a S4 or S5 TII trans with a turbo flywheel, clutch, slave cylinder, transmission crossmember & a Mazdatrix Turbo to NA driveshaft. You can also swap in a turbo driveshaft and rear end.

If your car is turbo, leave it be. The TII transmission is actually pretty strong, and is still used by a lot of guys running high horsepower drag cars.

 

well i mean for any rx, sorry.
i saw a bellhousing conversion for an rx to run the t56 tranny, i read that the gear ratio in the rx8 was damn near the same as the t2 trans
but i want to have a final gear ratio to hit higher speeds.
and with a 6 speed i figure acceleration would be alot better,
because my friends honda has a k20 swap and he had a 5 speed but then switched it for the 6 speed and it pulled alot better, and performed fairly well...

 

The 6 speed is the same basically as the 5 speed only weaker. Also if you were running a T-56, you would run about 1700 rpm highway, which is NO power for rotaries. Best to suggest a TII transmission, or the T-56 with an ungodly high rear end.

 

RX8
1st 3.760
2nd 2.269
3rd 1.645
4th 1.187
5th 1.000
6th 0.843

RX7 Turbo (S4 US)
1st 3.483
2nd 2.015
3rd 1.391
4th 1.000
5th 0.762 (0.806 JDM)

You're basically getting an extra gear in between 3rd & 4th on a standard 5 speed. Not to mention, a 0.843 top gear will kill highway fuel economy. With a 4.1 rear end you'll be spinning 3800 rpm @ 80mph.

If all you want is acceleration, use a TII trans with a 4.3 rear end. It'll be stronger and actually fit in a FB or FC transmission tunnel.

 

If your RX-7 has any real amount of torque I wouldn't use an RX-8 transmission. It's basically a beefed-up Miata transmission. The 6th gear is of very little value, because if you're driving an RX-7 fuel economy is clearly not an issue.

Dave

 

stay away from the rx8 tranny's

 

What he says about the extra gear between 3rd and 4th is the well known consensus.

 

ok cool...what about the rx3 (i believe) 4 speed tranny i hear its like a t2 tranny