can I run 993 brake calipers with 17" wheels and stock 964 brake rotors? I would like to do front and rear.

 

I run 993 big reds inside 17" cup2s. But also use a 993 rotor. I am unsure why you would want to continue using the 964 rotor? I think it will work, but your obviously not going to get the best performance.

 

993 rotors are much thicker. Not a good idea to keep 964 rotors with 993 calipers.
Incidentally I will be seling (4) 993 calipers with front adapters for 928 discs this summer. Going back to 964 setup.

 

to be clear - rears yes. stock rotor and mounting.
fronts need 928 rotors and machined adapters for caliper to hub fitting.
A very good upgrade especially if you have C2 rears. Big red fronts are not required even for track use, they simply add cost and unsprung weight with 3x cost of replacement front rotors.

 

I did'nt know the 993 rotors would work. I want to upgrade everything then. I just need adaptors for the front calipers right? Rear rotors have to be 964 for the parking brake right ?

 

2 different adapters for either 928 or 993 discs. 4mm offset difference. 928 discs are solid, 993 are drilled.

 

THANKS

 

Rears - 993 C2/C4 calipers with 928 solid or 968/964RS drilled rotors/discs, as these keep the park brake.

Fronts - 993 Turbo (Big Reds) or C2/C4 (S4) calipers, now this is where it gets tricky... adapters and rotor combo!

There are two types of caliper adapter, as stated above by user8, with a 4 to 5 mm difference!

Option 1 - 993 turbo 2 piece 322mm drilled rotors/discs or 993 C4 305mm drilled rotors/discs.
Option 2 - 964 turbo 322mm drilled rotors/discs or 928 GTS solid rotors/discs.

Most adapters off the shelf are for Option 2, not found one as yet for Option 1, but I know they exist...

 

993 rears are the same as 964 rears except that the 993 rear calipers have bigger pistons. The bigger pistons are necessary to balance the bigger fronts.

2 ways to use 993 fronts on a 964

Method 1, best and most expensive way to go
use 993 alloy wheel carriers, 993 32x304mm rotors and 993 calipers. You will also want to change to 993 23.8mm m/c and vac booster unless you have a 964 C4 which already has a 23.8

Method 2
using stock 964 steel wheel carriers, use aftermarket caliper adapters w/ the appropriate o/s for the rotors you use, 993 front calipers. Usually 928 S4 32 x304mm front rotors are used, but there are other options. As above 993 m/c and booster is recommended.

For track use you do want the bigger 993RS/tt or 964 RS setup, but not w/ stock drilled rotors. For this application you will want slotted or plain 32x322mm rotors

 

I bow to Bill's superior knowledge
Basically what I know, I learnt from his brake info doc anyway, see Bill's signature.

I never mentioned the 993 carriers as it's a whole different kettle of fish!

 

I've just put big blacks on the front with 993tt discs. The adapters were supposed to be be good for either offset depending on which way round they were mounted...but they didn't fit and still needed machining which came as no surprise to my Indy. Rear 993 calipers fitted easily on the original disc.
I haven't changed the M/C but have removed the bias valve internals. Braking is effortless and very powerful.

 

Anyone is interested in light weight high performance two piece rotors for your 964?

http://www.racingbrake.com/RB-Two-pi...p-9-p/2516.htm

 

^^ isnt stock also 17lbs?