rideshootanddrink

Excellent info Bill, thank you!

Ok, seems like the way to go:

Front: 993tt/928GTS caliper with 965 rotor + FVD adapter
Rear: 993 C2 caliper with 964 rotor and no adapter
MC: 993 C2 23.8 mm, are there any modifications required to fit this mc on 964C2? Is it a bolt on?
Proportion valve: WHICH ONE?

Now, if only someone knew why I wanna do this, as I'm actually pretty happy with my stock brakes

cobalt

I did not do the MC and I am quite happy. Pedal feel is slightly stiffer than my 94 turbo or GTS which both use the same brakes. If you want cross drilled rears you will need to go with the 964 RS rear rotors otherwise the stock rears and 94 turbo fronts or stock rears with GTS fronts for all solid look on 4 corners.

Why are you going to do this. To be honest my stock brakes were fine I happened to have spare set of front rotors and calipers so I decided to upgrade my C2. The improvement is tremendous. Not in the sense of stopping distance as much as modulation, control and far less dive. You don't have to be as hard on this set up as the stock brakes. No fade on the track (this was 3 days running 8-20min sessions a day with the 2 drivers) and better overall control, not to mention how much better they look.

So yes the stock brakes are adequate but the big reds are better.

Bill Verburg

The only reason besides, vanity, to upgrade brakes is for track use where thermal reserves of stock 964 brakes are wanting. All other things being equal the bigger rotors run cooler for a longer period of time.

Bill Gregory did a very nice write up on adapting the 993 23.8mm m/c to a 964.

The article was in the June and July 2005 issue of Pano

I thought a copy was here on Rennlist somewhere but I couldn't find it.

If you don't have access to the above, pm your e-mail address and I'll send you a copy.

The m/c size available for use on a 964 are 20.6mm(standard), 23.8mm(turbo) and 25.4mm(RS). The first is properly sized for easy application of boosted stock brakes by a very wide range of physical abilities, the second is designed for the larger turbo brakes for the same population. The last is designed for track use of the same turbo size brakes by the more physically fit end of the population.

The bigger the m/c relative to the slave cylinders(within reason) the better control is obtained from the system. The high hard pedal is far easier to modulate than the slightly softer stock pedal. The slightly softer pedal gives you more gain from the system(less leg is needed) at the cost of control. These are each compromised toward a slightly different end.

Rocket Rob

I will be changing my 2 pot calipers for 4 pot soon and need to order the proportioning valve. I'm having trouble seeing it on PET. Is this the correct part number 964-355-301-10 named "regulator"?

Thanks in advance.

Southampton76

Buy it here

http://www.vehiclecraft.com/Brakes/vciweb7.htm

Bill Verburg

Yes, that is the 55bar p/v that you will want for 4 pot 28/30 rears

PAOLOP

I think that rear 964 RS needs 24 mm rotors. not 28.
Paolo

Bill Verburg

That is correct, the 964RS uses the same size 24x299 rotors as the n/a 964 and 993, but they are drilled & vented 951 M030 parts rather than the stock solid face & vented ones.

The 964RS rear calipers used the same 30/34 pistons as the 965 and later 993. The 965 calipers want 28x299 rotors the 993 and 964RS want 24x299 as on the n/a 964.

demonfish

I'm losing the will to live on this issue..

Ok - with the current exchange rates, i feel now is the time to buy.

I'm getting a full front big red kit from FVD. (£1000) but i found a kit from GMP in the US for $1650 = under £800).... anyway... big reds up front.

For the rear - 964 RS rotors, part no. 951 352 041 91...

these will work with std 1992 964 4 pot calipers, but should be upgraded to 993 C2 calipers yes?

i just need all this confirmed by someone who with the knowledge...

thanks in advance!

Bill Verburg

Yes, they are the holey equivalent of stock 964 rears. Yes, use 993 rears calipers w/ the above rotors when a bbk is used in front.

demonfish

thanks Bill....

boxsey911

I've been looking a while now for some 993 C4 rear calipers to replace my 2 pots but have had not luck So I'd like to widen my search to other models.

There is mention in this thread of 968 calipers been used (but these are also hard to come by) so I've browsed a number of the PET catalogues and see a number of potential sources for appropriate small body 28/30 calipers including the 944T and 928S4. The recurring theme on part numbers is:

xxx.352.421.xx (422 for the other part of the pair)

Again according to PET I see:

928.352.421.03 is the part number for a 964 C4 rear caliper (left) and 928.352.421.00 is the part number for a 928 rear caliper (left).

Here's a picture of some 928 S4 rear calipers. They look an ideal candidate to me or am I missing something?

Bill Verburg

993 rear calipers are used to balance a bbk in front. No bbk in front? use stock 964 4 pot rears. Yes, 944t, 951, 968 and 928 rears use the same pistons and rotors and could be used if the bleeds and feed ar swapped.

boxsey911

Thank you Bill. No, I'm not fitting bbk on the front. I had seen earlier in this thread that the 993 C4 calipers could be used (but not the C2 or S variants from the 993). It's good to hear that there are a lot more options than this (especially since 964 C4 and late 964 C2 rears are also very hard to find on the used market over here).

Where in the car is the brake p/v situated, so that I can change it for the 55bar version?

Bill Verburg

the p/v is the round canister off the abs pump, C2 like mine w/ M220 have 2, a 964 C2 will only have 1