"the FC has a very well supported pinion." - glad we're on the same page
I will begin my custom BH project in summer as well ;o)

Robert

re my FC rear end post just above...

i talked to Ray, the owner, builder, brutalizer last night and apparently it had slipped my mind that he had engineered some additional pinion support.

this is a 3rd gen section but the FD and T2 FC use the same rear gears, other than the FC pinion is longer, so it is relevant as it shows that the OEM gears can withstand quite alot when properly supported.

BTW, i am not saying they are better than the cobra alternative, just that they may well be fine w some supporting mods.

howard coleman

Both options are sufficient when properly configured

Howard/Rob/Anyone... you guys ever get a chance to play around with your diff/subframe mounting? I will be dropping my rear subframe out here soon and am looking for some more ideas.

Zkeller has run Paul's subframe with success apart from the front diff bushings wearing a bit quickly. I will be running 300M axles, a T2 clutch-type unit in a stock FD housing with Paul's subframe (which is a work of art BTW) and I will eventually reinforce the casing with a PFS girdle. The loose ends for me at this point are the inner CVs and the ring and pinion which Carlos seems to be cleverly addressing.

ls1240z, is offering a new Cobra 8.8 IRS cradle adapter which looks pretty stout, and is currently under testing: http://www.v8rx7forum.com/v8-rx7-tec...naly-here.html

I have a upgraded subframe by Paul but it has not been installed yet. Has anyone been running some serious RWHP with Paul's mod, and if so, how has it been holding up? It was a little pricey but the design and build quality seem high.

My build is planned for about 500-550 RWHP and upwards of 500 lb ft torque for road racing. I am currently looking to purchase a Kaaz and 300m axels. With that power level, does anyone think it is also worth purchasing upgraded inner CV's or is that just for something above my power level?

The inner CVs aren't even available yet, but they're being worked on (I have sent parts in to be mocked and measured, but I still waiting for my manufacturer to get the ball rolling on this). There are only a hand full of racers like Ari, Adam S. etc who can really say when they begin to break. I speculate that it is somewhere around the 6-700 HP mark for a well sorted car or and probably just under 500hp once you throw wheel hop into the mix. Again this is speculation through hearsay and inference on my part since I have never personally broken an inner CV, nor does my car even run at the moment. At any rate, upgraded inner CV's should not be necessary for an RX-7 that is setup for road racing exclusively.

Been getting some t2 diff related questions so I thought I'd give this thread a bump.

I see that this thread still needs to be updated to include information on the new Cobra IRS conversion that is now available as well as further theory regarding pinion support etc.

Thank you Rob for this thread, it has been very educational.

I am working through a diff brace solution for my track car and will post my results.

N