does anyone know which other porsche used S4 or GTS equivalent brakes?
im trying to identify the other porsche models that are compatible to give me scope when i call breakers yards.

i will need to replace the discs on my car in the near future and im thinking about upgrading the whole lot. i know that its not strictly necessary for street use but i like the idea of greater fade resistance and increased feel. the easy option is to use some GTS calipers and discs and bolt them straight on to my S2, but ive also read that people use 993 turbo calipers and discs - are these the same and do they bolt straight on like the GTS parts?

the reason im also curious about S4 equivalence is in trying to track down some two piece hat/rotor combinations, and also investigating the brembo 'gran turismo' system which updates the 993 TT to 355mm rotors - i think this is the same size as mark A uses and he rates them highly.

 

I believe that you're going to need the adapter plates with ANY of the 4 pods. Depending on the adapters you use, you may also have to either go to a full S4 front suspension, or replace your front spindles with OB ones.
BEEN THERE/DONE THAT - The upgrade was WELL worth it!

 

Mark his S2 is an '86 and has S4 suspension and brakes already. Nick can bolt GTS calipers and rotors right up to it.

 

yes, nothing wrong with the 'S4' brakes - just wanting more!

 

If you already have S4 calipers in the front then the GTS or 993 Big Red's will bolt right up. The GTS and 993 Big reds are the same caliper. The only difference is the 993 has the cross-over tube installed on the other end of the caliper and the color red. That's because the 928 caliper is mounted on the rear edge of the rotor and the 993 is mounted on the front edge. If you get the 993 calipers, just switch the crossover tubes and the bleed screws. The only other Porsche that I KNOW uses the S4 caliper is the "944 Turbo S." If you go to this bigger caliper then you use the GTS rotor or the cross drilled rotor from the 965. P/N for the cross drilled rotors are 965.351.045.00 for the LH and 965.351.046.00 for the RH. To do it right you will also need the backing plates as the GTS are larger than the S4's. The P/N's are 928.351.083.04 and 928.351.084.04

This is a worthwhile upgrade. I did it to my 89 GT along with a 55 bar brake bias valve. It's a difference you can feel as well as measure.

Jim Mayzurk
93 GTS

 

jim, thanks for clearing that up for me, i thought the GTS and 993 TT had same callipers but wasnt sure. this should also translate then that whatever can be added to the 993 TT could also be added to the GTS/S4. i know brembo do an upgrade kit for the 993 taking the rotors out to 355mm with 2pc hat and rotor combo, this might possibly work with the 928?? its a pricey kit though, to buy new. in the end i will probably just get GTS callipers along with 2pc rotors!

by the way, who knows what are the bolt on options for the rear?

 

drnick,

As I read it, Garth put machined 993TT calipers on his GTS rears.

Here's a relevant thread: (Big Reds)

 

looked at the thread, sounds like the 993 TT rear callipers will fit the 928 rear and are the same size as the S4 front callipers. i wonder what kind of rotor is used?

 

jim, what is the 965 and do you know if the 993 TT rotors can be used on the front of the 928 or are they different?