Miles965uk

Hey does anyone know what the brake setup (calipers & discs) was used on the 3.8RSR?

I know it had RS rear arms so did it just have RS discs and RS calipers?

I have read some things that it had turbo S brakes but i dont think thats right as if the rear arms are NB ones then the hub were too which are different offset to turbo. seems theres alot of BS written out there as the stories are different!

I am converting my 3.6T to NB arms and want to go for the exact setup as the RSR.

Cheers!

Cupcar

Lookin' quickly at the RSR parts book I find all the critical parts discs, calipers have "R" for racing part next to them and none of the part numbers appear on the street catalog. The numbers are close, but not identical so there may have been supercessions of some of the parts.

Miles965uk

Thanks for that, I guess i want to see one in the flesh now but what i like is the 5mm rear offset they used on the wheels which im trying to work out if the hub and disc were the same offset as the RS. I cannot see the 3.8 having a different size at the rear of dics.
thanks

Cupcar

The rear axel shaft and CV joint package of the 3.8 is the same as the Euro RS, and I note the rear disc is a "951" part number like Euro RS as well (implies a thinner disc than Turbo). The rear hubs also have "964" instead of "928" part numbers normally on Turbo.

This tells me that the disc offset in the rear is probably the same as a normal C2 and not the same as Turbo and that the track increase is done with rim offset rather than at the hub.

Geoffrey

The track increase was in fact due to the offset in the wheel since the RSR uses the Euro RS trailing arm (narrow body, not turbo).

There were several different brake packages for the 3.8RSR depending on year and whether or not the teams continued to use the Porsche setup or used an alternative setup.

Miles, I think the question you would like answered is what brake setup do you want to run on your car NOW.

The factory ran a setup similar to the Euro RS.

The part number for the front disks are 965.351.045.90R and ...046.90R which implies that they are Turbo or RS front disks that have the stud holes enlarged for centerlock drive dogs.

The part number for the calipers changed over the years as they were updated. The original part number is 965.351.425.10 R and ...426.10 R but were later updated to 993.351.425.10 and ...426.10. The former being 3.6 Turbo calipers and later 993TT or euro RS calipers

The rear brake disk is part number 951.352.041.70 R, again, implying a similar disk to the Euro RS but again, machined for the centerlock drive dogs. It is not the Turbo rear disk as it has a completely different offset due to the wider trailing arms.

The Rear calipers are unique to the RSR in that they have a 964 part number rather than a 928, 965, or 993 part number as the various street versions have. I believe them to be similar to the 3.6 Turbo rear calipers but narrowed to accept a 24mm rotor. The question is what is the thickness of the rear rotor, 24mm of the C2 variety (likely) or 28mm of the turbo (not likely). If the former, then the calipers need to be narrowed (Cup Car and Euro RS), if the later, then the 94 C2 Turbo will work.

Cupcar

Cool information Geoffrey. Here is picture of the RSR rear caliper and disc.



Can't tell for sure but the disc looks to be the 24 mm variety. The caliper looks like a 993 caliper painted red.

My bet is the rear uses a 993 rear caliper, but red in color with modified 24 mm thick Euro RS rear discs to work with the centerlock dogs.

Porsche superceded the Euro RS rear caliper to the (black) 993 rear, the original is NLA.

Miles965uk

thanks alot Cup car & Geoffrey, it seems so that the dimensions are the same as the C2/RS then.

The disc in the pic does look like its a 24mm but the brakes are red which mean like you said be narrower 993 ones painted.

I thought i could swap my turbo hubs over onto the NB trailing arms but so far no joy, so i have stuck with C2 hubs and I can get hold of a set of RS copy type discs for now ( do the genuine RS discs fit a C2 Hub?) I am going to use my current calipers even though the width is larger i may make a 2mm spacer inbetween the dampers and back of the brake pad to get it right.

Cheers!

Christer

Miles

I have Euro RS brakes on my C2, and they fitted straight on except for the adapaters for the front calipers. I believe Turbo 2 calipers and discs on the front, and 993 rear calipers with 964RS discs at the back (I think they might be the same as the 968 rear disc).

One question though, you have a 3.6 so surely the RS brakes are not an upgrade...are they...? (I am sure I have missed something here, but I do believe in the 'no question is a stupid one'...) right?)

Geoffrey

The 964RSR uses the steel 3.6 Turbo front hub carrier.

Here is the later front RSR (332x32mm) non-endurance (endurance is 380x32mm) brake package which uses a 993tt caliper.

Cupcar

Geoffrey- Is that a Wrightwood brake adaptor with an Alcon 332X32 disc pictured above?

Geoffrey

Yes it is. The rotor is either an Alcon or an AP Racing unit. The new rotors available are slotted rather than drilled (YEA!!! Finally!!!)

MB965

Geoffrey,

Something not making sense here. My '94 Turbo 3.6 front calipers are radially mounted. The rear calipers are axially mounted.

Anyone making a brake rotor adapter for the rear that still allows use of the hand brake?

Any idea on the cost of the front rotor adapter and rotor? It would be nice to actually wearout the front rotor, rather than replace them due to cracking.

I have considered using Turbolook rotors (solid) and having them slotted, but the cost is more than the Turbo 3.6 rotors.

Mike

Geoffrey

You are correct, the 3.6 Turbo uses the same caliper as the 993tt.

Glenn from Denver

I find this thread very interesting. I have just gone through the process of replacing f/r rotors and pads on my car and found that the previous owner of my car had done some bastardization of parts.

In front, I was able to mount "standard" racing rotors...AP 380x32 floating rotors.

In the rear, it's a different story...the original replacements that I got from CDOC were true RSR rear rotors. They looked very much like the rotors that are seen in Cupcar's post above. I believe that they are 24mm thick. The problem was that they didn't look anything like what I had on there to begin with...they were much smaller in diameter, thickness and had a different offset. After attacking my original rotors with a wire brush, I was able to make out a part number on one of the rotors (965.351.044.00). This is the part number for a Carrera RS FRONT rotor. Apparently, the p/o had made the change at some point and he, of course, didn't tell me anything about it!!

Oh, well...problem is now solved and I'm up and running again.

Cupcar

Here is a picture of an RSR factory front set up. Looks like a normal 3.6 Turbo set up to me.

Putting this together, the RSR front is a 322 X 32 rotor same as Turbo 3.6 and caliper is same as well. The rear is same caliper as 993 with the same disc as Euro RS 299 X 24. This means the Turbo 3.6 has a thicker (28 mm) rear disc than an RSR.