JamesE

I have 993tt breaks on my (was 3.3) turbo. They fit perfectly with no adjustment.

ttAmerica RoadsterAWD

Thanks, guys. So seems I have the 3.3T front calipers. Are these calipers used on the rear of 993tt? Maybe I can use them and the front rotors for the rear??

cobalt

Pad size is the same for 993TT rears the rest is different. The 993TT uses 2 smaller 28mm pistons and is axial mounted instead of radial.

Here are some pics of the 993TT rear caliper. Second caliper in on 1st photo (not the one in the foreground) . Same size as the medium S4 using the same 48 x 132mm pad but smaller pistons.

More than likely you can sell the fronts and buy new. IIRC sunset sells the 928 GTS calipers for around $300+ ea new just need to switch bleeds and feeds.

ttAmerica RoadsterAWD

Hi Cobalt. Thank you for the info thus far.

What do you mean switch bleeds and feeds? Are the 928 GTS plumbing different from the 993tt plumbing on the calipers?

cobalt

Yes,

The 928 runs a trailing caliper vs leading so the bleed valves would be on the bottom if you mounted them to a 964. You would need to remove the feed pipe and switch it with the bleed valve. Simple process in theory although damaging the factory paint might be an issue.

ttAmerica RoadsterAWD

......but, If I order and get 993tt big reds, then I don't need to do anything..... am I correct?

dunavantent

I think you'll need the 94 3.6 rotors. Someone will post a photo for you.

cobalt

My understanding is that your car started life as a 92 America roadster. So it would have been supplied with 1992 turbo brakes or medium S4's up front and the turbo calipers and rotors in the rear along with the electro-hydraulic 23.81 master cylinder. Then all you would need to do is buy the 993TT or 94 turbo (same part number) front calipers and switch to the 94 turbo rotors. P/N 965.351.045(046).00. the rotors on your car can be used although you would not gain the benefit of the bigger pad as the surface area would be less and part of the pad would run along a non machined surface towards the inside of the rotor. Otherwise it is a direct bolt up.

However, if you are using different uprights or your car is based on a C2 cab with widebody conversion you would need axial to radial adapters suited for the 94 turbo rotors or the 993TT rotors and would then need to use the applicable offset rotor based on which adapter you choose. Unfortunately, this change would require replacing the rear calipers also to 993N/A rears along with some other minor changes assuming your car is based off a stock C2 although IIRC it is a 92AR.

The rotors on my 928 above and C2 are stock 94 turbo rotors. You can tell by the cast hole configuration of 5/4 vs 4/3.

ttAmerica RoadsterAWD

Thanx, Cobalt. Yes, I already purchased the 993tt front rotors and are installed. I'm waiting on the *real big reds* as I've ordered front calipers for 993tt. I think I'll be ok with the current rear setup. I'll essentially have the complete brake setup as the 3.6T and not like the 993tt. I think this is correct.

JamesE

I love threads like this. Devil always hiding in the detail.

tasracer

im sooo cconfused... need to reread.... anyways got my car out today

ttAmerica RoadsterAWD

Well, if you want a blow by blow, go to the NA 964 forum and look under "EVO uprights, EVO carriers, GT uprights".

cobalt

Yes your set to go. I now understand you have the evo uprights so you will need the 993TT rotors. The difference in braking power from the 94 turbo to 993TT is nominal. The majority of your stopping comes from the front so you will be fine. You can always play with pads if you want more aggressive braking. There is a significant improvement as you move from stock pad to street performance on up to racing pads. Although there are trade offs. Squealing and dust do increase as you go up the line.

So are you going to paint your rear calipers to match or are you going to replace them with red versions. Also you are now set up for aluminum hats if you feel you want to go in that direction.

ttAmerica RoadsterAWD

The rear calipers are already red. Previous owner had them done.

Where can I get aluminum hats? Do I just unbolt the iron hats from the 993tt rotors and replace with aluminum?

cobalt

There are many places you can start here.

http://www.zeckhausen.com/StopTech/consumables.htm#Hats

No affiliation.