eurostarjohn

Hello everyone, I'm new here but recently bought a 1986 944 Turbo track that car needs new discs and the buildsheet provided by the previous owner indicates the car was upgraded to "S4" calipers with 993 cross-drilled discs in the front. So, I ordered the S4 pads and they were an exact fit however I'm having difficulty identifying the old front discs as there aren't any markings of any kind. So I did some research and bet on 993 351 044 01 single piece discs from a 911 C4 '93-'97 to fit as they are also 304mm however the C4 hat is taller that what I already have and so the caliper will not connect correctly with the spindle as the disc interferes. Now I'm thinking that I may have 928 S4 or 968M030 discs cross-drilled units. In any event was wondering if anyone can identify what I might have here before guessing again.

lart951

To me they appear to be 88-89 Turbo S m030

bw993

Looks like you need 968 M030 rotor P/N 965-351-041-01 (right) ; 965-351-042-01 (left)

eurostarjohn

Thanks for the feedback, I was completely blown off course by the 993 reference in the car's build sheet and went in that direction but should have done more research as I'm not exactly Porsche proficient. Are the M030's cross drilled?

bw993

If you want non-drilled rotors the part numbers are 928-351-045-01 (right) ; 928-351-046-01 (left)

rlm328

You want the none drilled rotors.

jasonlp

I like slotted cryotreated for track. Link below has Turbo S/M030 sizing.

http://www.frozenrotors.com/category...otors-slotted/

eurostarjohn

I like the frozen rotor option.

eurostarjohn

Thanks for all the information and suggestions. I'll probably go with the same cross drilled configuration on a replacement set and see how long they last. Curious to see how resistant they are to cracking and monitor them from new. I only ran one event with the old set but the cracking around the holes definitely got worse upon inspection after my last event.

rlm328

Drilled rotors have a tendency to crack. The cross drill has out lived its original purpose which was to allow the pads to out gas without building a boundary layer gas between the pad and the disk. The modern pads do not have this issue. If you have to have something get slotted.