kx5fast

I have done countless searches and cannot seem to find something I know I read here on Rennlist.

I have a 1993 RS America which I use soley for the track. I did the Big Red upgrade on the fronts some time ago, which, with an adaptor, was a bolt on and go type installation.

I decided to wait on the rears until my current RSA rotors were toast, which they now are.

I cannot for the life of me find the rotor with the proper offset that goes on the RSA hub and fills up the Big Red Caliper.

I have the stock 993TT rotors, and the offset is nowhere close. Cany anyone help?

(BTW, if anyone needs some 993TT rotors, PM me.)

Rod

Bill Verburg

The best you will be able to do on the back of a 964 is to use n/a 993 rear calipers. If you want drilled rotors use the 968 sport rotors 951 352 041 91. They are the same size as 993 rear or 964 rear but w/ cast in holes.

The 993tt or 993RS big red caliper and rotor can't be fitted to the back of a 964 as you have found. At least I have never seen it done.

garrett376

I don't know if you'd really need that much rear brake (an S4 sized rear pad), would you? I think the majority of 911 brake problems on the track are due to heat issues with the front brake system, not the rears. My race 964 has no brake issues (has late 965 brakes: Big up front with 993/C4TL rears), even after 45 minutes of diving in late to just about every corner in sprint races. I don't think I'd benefit at all from more rear pad or rotor; it would just add more weight!

Geoffrey

I have 993RS (larger pistons than big reds in the same caliper) rears with 322mm rear rotors on my race car. The only issue is that I had to remove the parking brake assembly and cut a tab off the control arm because it uses aluminum hats. I removed the brake pressure limiters on the ABS pump and wish I had more rear brake bias.

Bill Verburg

That was going to be my next suggestion, most Cup cars run w/o the rear p/v.

Unfortunately most of us need a parking brake. I suppose you could install the separate Carrera GT ones

Geoffrey

I don't miss it.

Larry Herman

My car has the 944 Turbo S rear calipers and drilled rotors, no proportioning valve, and I have all the rear brakes that I need.

Bill Verburg

You don't have to deal w/ NYSDMV w/ yours

kx5fast

My motivation was actually two fold. As far as more brake is concerned, I seem to have more than enough. (Rear p/v taken out)

However, I eat rear pads like they are going out of style (Pagid Blacks up Front and Oranges on the rear). My hope was, more pad surface area, less pad wear.

Also, my rear rotors are shot, or will be after next weekend, so I gotta buy rotors anyway.


The 993TT calipers appear to bolt right on.

Geoffry, can you be a little more specific on the tab on the control arm? Also, is the hub/hat combo from another 993? Or, asked another way, will the 993RS hat slide right on, and are they readily available? Any sources for parts would be great!

The ebrake is already dissassembled, so that is not an issue.

Thanks for the input.

Rod

kx5fast

Thought I would throw a picture out of the car.

I just like looking at it!

Rod

Geoffrey

There is not a factory rotor that will work with the big red caliper, so you need a kit. The kit consists of an aluminum hat custom made for the correct positioning of the rotor, and custom made rotor from AP Racing. The calipers are also machined for the correct positioning for the 322x32 rotor and the 993RS caliper is used, not the 993TT which has smaller pistons (less pressure). The kit is from Wrightwood Racing, but you cannot buy direct, you need to go through a distributor. I used Joel Reiser from Reiser Technik. After being on the track yesterday again, I take back what I said about the bias. It is very, very good. I shut off the ABS to do a test and the rears are very well balanced.

Here is a picture of the control arm. If you look at parking brake assembly, there is a rectangular casting on the forward facing part of the assembly between the two caliper mounting bolts. It extends out toward the outside of the car and hits the rotor hat bolts. Removal is required.

kx5fast

Thank you Geoffrey.

Rod