FormulaRX

I plan on doing big reds for my C4. 993tt front calipers, 993 rears, 965 and 951 brake rotors, etc. Going the full setup...but for those of you who did this, will I need a proportioning valve upgrade too? Or will I be ok? Thanks

Pacific German

Factory prop valve on a C4 should be adequate.
Im running 355 / 328's on mine.

FormulaRX

And what do those numbers refer to? Thanks

deadendd9009

That would be rotor size in mm

Pacific German

Yeah, sorry.
Its the Brembo GT System

Steve Weiner-Rennsport Systems

No prop valve needed for those brakes.

FormulaRX

Is there a link somewhere to this GT system? How do they differ from the oem big reds in terms of size? Are they better/cheaper?

Pacific German

$7390 front and rear. Id say they are more expensive.
http://www.racetechnologies.com/prod...0?vehicle=9514

FormulaRX

Thanks! I'm guessing you have to ditch the parking brake with the gt kit?

Pacific German

Nope. Its fully functional.

Spyerx

I have no proportion valve on my Brembo setup (removed it), and yes parking brake works fine.

The documentation for the fitment says that you need to have at least the C4 valve which is what I'm guessing the piston bias is based on.

That said, I've locked my car up before I got the ABS working again and it still locks the fronts first (and I have the big 6 piston fronts for the 993, I have EVO uprights).