bullbear

Hi all, this is a two part question i guess, for a 87' 951...

i) for those who club race, whats the biggest calipers and rotors that you can put on to remain in stock class?

ii) what are the biggest calipers and rotors, using parts from other porsches, that would fit a 87' 951?


thanks much!

jerome951

I assume you're asking about PCA club racing.
I can't answer the 2nd question, but to remain legal in a stock class you have to use the factory calipers offered on that year of car. Rotors and pads are free (meaning you can use anything you want). Larger calipers will bump you into Prepared.

I strongly suggest downloading the PCA rules from the club racing website and reading them carefully as you prepare your car.

bullbear

Thx for the response Jerome. I have carefully read the PCA club racing rules. I guess my question should have been - the calipers and rotors that came on the 87' 951 are the biggest offered for that year and model? I guess I can cross-drill them for better cooling...

rlm328

Cross drilling won't do that much for you. You will want to duct them though in order to redirect cooler air on to rotor. The brakes are more than sufficient for stock horse power requirements. Get some decent racing pads like Paige or PFC. You will also want to change your brake fluid out to something like Motul 600 or some other high temp brake fluid.

Oddjob

The stock calipers on an 87 Turbo are the only calipers legal for stock E class 951. There were no factory brake upgrade options available for the standard 951.

bullbear

thx Jim. So its change them and risk moving up a class or two...

On that note, do you know what the factory specs are for the F/R calipers and rotors? I cant seem to find it...

Do you guys just do custom ducting to cool the brakes or is there some porsche part that helps cooling?

thx much all you experienced club racers!

Oddjob

Specs = what? Part numbers? Dimensions of the rotors? Caliper piston sizes? Or what specs are you looking for?

Either cool brake kit ducting or 968 upper and lower scoops. I prefer the 968 scoops as they are a cleaner install, lower maintenance and don't get in the way of oil coolers/lines and other junk around the wheel wells.

bullbear

Thx for the 968 tip Jim! Will look into that. Unless you already have the part numbers handy...

As for specs, I would like to know all of those mentioned if possible.

Thx much in adance.

Van

I think the simple answer is to brake less and go faster...

I'd recommend you stay away from cross drilled rotors, I find those develop cracks quicker than solid or slotted.

As Sir Jackie says, "Be early and gentle with the brakes"

944hal

I'm Club Racing an '87 951. Bumped it up to SP3 from stock. The stock calipers are still adequate. I'm using Hawk DTC60's up front and Blues in the rear. I have a set of Turbo S calipers that I tried but the right calipers keeps sticking, locking up the wheel on hard braking. I've rebuilt it twice (new seals) and it still does it. The stock calipers are fine, so I'm assuming it's the S caliper that's the problem. Any advice beyond new seals?

Van

Possibly you have a damaged piston - It might have a burr or be out-of-round.

Oddjob

Do a search on this forum (951 board) for "968 brake scoops" and there will be several threads that show the parts, install and part numbers. If you dont have 968 control arms, you will need to fab a bracket to hang the lower scoop off the sway bar drop link.

Oddjob

Certainly will be more prone to lock-up w/ the larger calipers.

Were you seeing uneven pad wear in that caliper? Car pull hard to that side when driving straight?

Possible that the side locking up is the one working correctly, and the other side is not generating equal braking power (problem w/ the other caliper).

MarkRobinson

I bedded my race car setup on my 951S: ran great, no odd lock-ups.
355mm RB on a custom Brembo hat, stock S4 calipers with seated pads.

944hal

I measured the pistons and checked for burrs, seems OK. Coming in off the track, when the brakes are hot, you can hardly turn the right front wheel. The left front has drag, but turns. So I'm thinking the left side is OK. Car does pull to the right when trying to drive straight. Pad wear is pretty even. I agree bigger calipers would be more prone to locking up but these are uneven right to left.