hey guys,

just picked up a s5 fc up off a mate pretty cheap..so im building it for next yrs drift series here...im a nissan/toyota boy, so mazda's are new to me haha
realise some people may not like my idea, owell lol

anyway, questions are:

1) how strong is an FC chassis? what hp/torque has anybody experienced any twisting? (will have a full weld in cage & seam welded)

2) how strong is the IRS rear end? as im also considering converting it to solid axel if its not going to hold up?

3) any "weak" spots in the chassis or anything i should be aware of?

anyway, reason for asking these questions is im putting an LS9 in my FC...so will have roughly 400rwkw & around 900nm torque
so yeh, as i said some people may not like the idea... haha

cheers,
Andrew

 

you wont be able to twist the chassis... these cars are way better than tin can 240s.

 

670lb.ft is no joke but neither is fc stuff. you may want to pack an extra rear end but i hardly ever hear about anyone blowing up a turbo diff. there will also be no flex with the fc when compared to a pos s chassis. the b pillars on the fc and fd are huge for a reason.

 

Get a new LSD. The S5 is viscous.

 

1. very strong, like stevensimon said the B-pillars are huge. Plus if your running a cage you shouldn't have any reason AT ALL to worry about it.

2. You can "upgrade" to the Cobra Mustang's IRS but really TII diffs and axles are pretty damn strong from the factory especially when you put in a aftermarket diff, damn near bullet proof. Just make sure it's TII and not NA.

3. No notorious weak spots but if your doing a cage already i'm sure your gonna be bracing a lot of other spots too. Strut towers and under fender braces are pretty much the norm.

My suggestion with the Mazda diff is to get the Mazda comp mount and a pinion snubber. That way it won't move under all the torque your LS9 makes, other then that, welcome to the RX7 club. Hope your build goes good and post some pics up.

 

TII Axles suck. i always brake them with 250whp drifting. driveshaft shop can make some better axles for around $500+ and you'll never have to worry about it again.