Gearbox options for replacing 240z autobox with RX8 6 speed??

SeanDezart

Well-Known Forum User
Has anyone considered that the RX8 has much less torque than a Z (never mind a modified one) and that this might be an issue to the gearbox life once swapped in ?
 

johnymd

Club Member
I would like an 6 speed so I could run a tall diff and still have 5 close together gears and still have an extra gear for getting to the track. I think this is the only reason to want to go 6 speed IMO.

Other than this, I'd just be happy to stay with the s14 and quick shifter which is superb.
 

SeanDezart

Well-Known Forum User
I would like an 6 speed so I could run a tall diff and still have 5 close together gears and still have an extra gear for getting to the track. I think this is the only reason to want to go 6 speed IMO.

Agreed...although I found the quick-shift a bit 'brutal' for a road-car. Trackdays = perfect !
 

johnymd

Club Member
I’ve been side tracked by a new project so I got nowhere with this. May resurrect it when my stroker engine arrives. Until this I’m very happy with the s13/14 box.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Still interested in Sean’s question on this - are there any known specs for that ‘box in terms of it’s torque capacity? I would wager it’s not made specifically for the RX and is used in other cars. My mate’s RX8 PZ was a hoot to boot around the twisties but had so little to with a quoted 160ish lbft max.


By contrast his twin turbo RX7 was a real animal but even then it was only c. 220lbft if I recall correctly.

I understand as a rule of thumb, decent manufacturers build in a 30-40% margin on the gearbox for longevity. Happy to be corrected / educated on that.
 
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