I did see on OS Giken USA that the 5-spd gearset is indicated as available for FD3 box for ~$2,400. Yet to be proven, but it should fit in the RX8 5-spd casings. It uses the OE Mazda bearings, synchros, etc. but the internals might need to come from the FD box. Somebody would have to figure that out.

Also, Mazda Motorsports USA released a 6-spd gearset for the NC Miata which may fit in the S2 casings. About the same price; $2,750. I posted the news release in the forum racing section. It needs further investigation wet the RX8.

https://www.rx8club.com/rx-8-racing-...8/#post4992124

the CD009 will be stronger though, but requires the full PPF delete conversion as well.
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Look like perfect gear ratio for turbo
but I need to know if fit s2 transmission.
have different alternative to buy.

 

^^all I’ll say is “run away, run away”, good luck there.

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Cd009 and 8.8 ford explorer.
Does anyone know the best combination with the differential?

I'm between 3.73, 3.55. Sometimes drag and street race.




3.73 ring & pinion

3.55 ring & pinion

 

3.73 minimum for a turbo street car, but you could go taller if you want.

there is a 3.727 in the Mazda 8” diff if you can find one from a 1988-1993 (?) Mazda B2600 2WD USA truck. It requires a bushing on the pinion shaft bearing surface to fit in an RX7/RX8 diff. I did manage to find one in good condition.

https://www.rx7club.com/3rd-generati...rs-fds-688203/
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apparently a very small mod made to 4th gear on the S1 6 speed can increase the torque capacity from a LOT
https://neatgearboxes.wordpress.com/...x-circlip-mod/