RS92 brakes on SC

[YvesSC-3L4]

I've just bought at a good price a set of front 964 turbo/'92 RS brake discs ( 302 mm diameter x 32mm thickness ) and calipers and I wonder what kind of adapter and brake fluid fluid line change I need to put them on my '80 SC with boge strut .

Will it fit 7x16'' Fuchs ?

Thanks a lot for your help

Yves.

[Eric Mckenna]

Yves,
I do not think they will mount up behind the 7x16 fuchs.. if they even do. it will be a VERY CLOSE close. Good luck!
Good luck! those are a great set of stoppers!

Eric

[ChrisBennet]

They will probably fit behind 944 7x16 Fuchs. 944 7" Fuch have the same offset but more brake clearance. I ran my 928S4/993 brake under them and I sold my 7x16 944 Fuchs to someone why runs Big Reds under them. ("Oh but everyone knows you can't run Big Reds with 16" wheels!")
-Chris

[Bill Verburg]

YvesSC-3L4, the calipers can be used, the rotors cannot, you will also need to update to a 930 boosted m/c

Read this;
General Brake info

and this
Brembo adapted to an early car
you will need a setup similar to the second reference

Your calipers setup w/ the proper front rotors(available from Movit among others in Europe) and stock 930 rear rotors is the best all around compromise for a 911(IMNSHO)

CB, What rotors is your friend w/ the Big Reds under 16s using?

The 322mm rotors that should be used, will push the Big Red radially a few mm too far for use w/ 16s

[ChrisBennet]

Originally posted by Bill Verburg

CB, What rotors is your friend w/ the Big Reds under 16s using?

The 322mm rotors that should be used, will push the Big Red radially a few mm too far for use w/ 16s

Bill,
I don't know. Here are my "data points" if you will:
Case 1: The first guy I knew who did this was running B.Red's under 944T 8x16 Fuchs.
Case 2: The 2nd was running them under 944 7x16's Fuchs. He said it required removing some material from the calipers.
If they used a smaller rotor (930?) in order to fit this were they gaining anything?
-Chris

[Bill Verburg]

If they used a smaller rotor (930?) in order to fit this were they gaining anything?

Yes, it is well known that w/ 8x16 944 Fuchs there is no axial problem and that spacers should be used w/ 944 7s

None of the calipers will have an issue axially w/16" wheels if 304mm rotors and 944 wheels are employed.

The issue is that the Big Red is ~10mm taller(radial displacement) than a 993/S4 and needs that much more rotor radius to fully seat the pads on the rotors. If the Big Reds are used w/ 304mm rotors there will be a few mm of pad hanging in the air.

The normal Porsche Big Red rotor is either 322, 350 or 380mm.

There are some folks that have machined the 322s down to ~315 or so to fit in the 16s. I was just curious about your friend approach.

[YvesSC-3L4]

Thanks a lot for all this infos !

Chris : I didn't know this difference between 944 and 911 Fuchs ! Do you have any Fuchs serial Numbers that can be used to differentiate one from another ?

Bill : Great site Do you check all of the setups you mentionned ?? . I didn't catch why I cannot used my rotors ? Aren't they just like 930 ones ?

@+ Yves.

[ChrisBennet]

Originally posted by YvesSC-3L4
Chris : I didn't know this difference between 944 and 911 Fuchs ! Do you have any Fuchs serial Numbers that can be used to differentiate one from another ?

I may have mispoken when I (& Bill) said the "944" Fuchs have more brake clearance. I know the '86 944 Turbo 7's and 8's had more brake clearance.
7x16 944 Turbo 951 362 115 00
8x16 944 Turbo 951 362 117 00

The last 2 digits may vary. Look for the "951" in the part #. You can identify them by the deep lug nut holes. The picture below may 9x16's but the lug holes are the same deep kind I'm talking about.
-Chris

[Bill Verburg]

The deep lug holes are a hallmark of the 944 Fuchs they are a sign that even though o/s is the same as 911 there is more room behind the spokes for calipers. They are essentially a higher o/s wheel w/ an integral spacer to net out to the +23.3mm needed at the front of a 911. The wheels w/ the deep lugs are the 944 7&8 and the 930 9

Do you check all of the setups you mentionned

Yes!

I didn't catch why I cannot used my rotors ?

As w/ wheels rotors have an o/s. The factory method of measuring rotor o/s results in 35.25 ± 0.1mm for SC front, 35.7 ± 0.25mm for '78 - mid '80 930 front, 56.7 ± 0.1mm for '81-'89 930 front, 76 ± 0.2mm for SC & 930 rear

Later rotors will all have very wrong o/s for use on a 911

also the generally available '80 on front 930 rotor has the wrong o/s for a narrow body car.