Ruairidh

I've a set of 993 brakes that have been on my shelf since 2004 for fitting to my C4, and I may even get around to fitting this summer. I think others have done this and, yep, my understanding is that this is the easiest route to get 964RS brakes onto my car.

garrett376

It's funny - the dealer sells NEW Big Black Calipers (same size as Big Red) for cheaper than new 993 S4 front calipers....

Jamie Summers

Geoff,
That would explain things then ! I was under the impression that the 928S4 was a 304 rotor, and as such smaller than the 964 Turbo rotor. If they are the same size then there is no issue ie I already have the same set up as the Euro RS. If that's right then the 964 Turbo, 944 Turbo, 928S4 and 964 RS rotor are all the same size ???? This doesn't really ring true though as I'm sure the only Porsche drilled rotor that is the same size as the 928S4 is the very rare and expensive 968MO30 ???
Still not sure I'm any the wiser here..........

Jamie

Christer

the RS definitely has a 322mm rotor though....so why does the 993 with the same caliper use a 304mm......? I guess Bill or another expert can chime in if they see this...

Jamie Summers

Christer,
Agreed, that seems to be the issue !!!! Brings me back to original suspicion that there is something different in the hub mounting on the RS which pushes the caliper further out radially to allow use of a bigger rotor - though this doesn't really tally with what Geoff is saying. Where's Bill when you need him ???????

Jamie

Red rooster

Jamie,
The 964 3.3 turbo/ 964 3.6 turbo/ 944 turbo / etc rotors are not the same !

The 3.3 964 / 964 RS use the same 322/32 crossdrilled rotor . The last 928 S4 used a 322 solid rotor NOT crossdrilled but with a wider pad area .

The 944/968 stuff use a variety of rotors , maybe with different top hat offsets ?

The 993 NA uses a 304 crossdrilled rotor so that 16 inch wheels could be used .

The 993 TT used a 322 /32 rotor , crossdrilled with the same pad area as the last 928 S4 !!!

Generally to make a bracket to convert from radial mount standard 964 calipers to axial mount 993/RS calipers there is a clearance issue which makes the 322s the best choice .

I was interested to see if someone had addressed the conversion brackets to use 304s on your car because of the 16 inch wheel issue ( better snow tires !! )

I still think it would be good if you measured your rotor diameter.Please !!!

All the best

Geoff

Bill Verburg

First you need to know what was available, pre-monoblock caliper

There are 3 sizes of multi piece, 4 piston, Brembo caliper used on all Porsches
Small
Medium large
Large

They come in 2 different configurations for mounting
Leading
Trailing

They come in 2 different mounting styles
Axial
Radial

Most come w/ different piston sizes.

Various colors were used Red, black, silver, yellow were th most common

The n/a, non RS, 964 are all small, black, leading, axial mounts- front 36/40, rear 28/30

944t, 951, 968, 928 and 993 used different versions of these calipers, the primary difference being the external plumbing needed for trailing mounts.

964 small 4 piston front/2 piston rear


964 Smalls f/r


993 front(powder paint & script by owner) medium large, leading mount also used in Black on 965 3.3t, 964RS front . Trailing mount versions of these were used in black on 928S4.

993front medium large, rear small




993RS fronts installed 322x32mm rotor


993RS rears installed 322x28mm rotor


993RS front on a 322x32mm 993tt/RS rotor w/a 964 hat


3 993RS calipers, from left stock rear, modified for 911use rear, front


A & M SC calipers on left, 993tt rear top right 965 rear bottom right


965 rear mounted ona 911 w/ 930 309x28mm rotor


993RS rear caliper top, 993tt rear caliper bottom


All of the different sizes

Bill Verburg

Now as to what was used where

stock n/a 964 C2 and C4 and RSA used the small, leading, axial mounts f/r 36/40 front 28/30 rear on 298x28mm front and 299x24 rear rotors

stock C4TL used the same fronts but w/ small leading, axial mount 30/34 rears on 249x28mm rear rotors

964RS ROW front used the medium large, leading, radial mount 36/44(same as 993front, same as 928S4 front except S4 is trailing mount) on 322x32 mm 1 piece rotor , rear used small, leading, axial mount, 30/34 on 246x24 mm rotors

964 C2 TL used the same front setup but rear was 249x28mm rotor

965 3.3t front used the large(aka Big Red, but also available in black), leading, radial mount mount 36/44 on 322x32mm rotors, rear used small 30/34, leading, axial mount on 299x28mm rotors.

965 3.6t used the large Big red fronts in place of the previously used 993type medium large fronts.

the medium large caliper aka 993,928S4, 944M030 can be used on either a 304x32 or 322x32 rotor but the large aka Big Red can only be used on a 322(or larger) x32mm rotor.

The 993 front and Big Red front are identical calipers except for the pad height so they use exactly the same caliper adapter when needed.

Bill Gregory

That's incorrect. In the Panorama "Braking System Basics and Modifications, Illustrated With a Guide for Improving the Brakes of the Porsche 964" article from last year, which is also posted on the web for non-PCA members, it says ...."Note the medium S4 black calipers used on the front of the 993 C2 and the Carrera RS/Turbo 3.3 are different castings, to work with their respective 304mm and 322mm discs". If my pictures weren't still in disarray from changing systems, I could find and post the pictures to illustrate the difference.

Bill Gregory

Again, that is incorrect. The 993 front caliper is meant to work with a 304x32 rotor while the Turbo 3.3 and 964RS are meant to work with a 322x32 rotor. While they are awfully similar and use the same pad, they are different castings, confirmed by Bob Gagnon and myself. Now I'm going to have to go find the pictures.

garrett376

I hate to be incorrect (or not thorough, I guess)... I remember Bob showing me his various array of his cup car vs. big setups... I remember that in addition to looking different (meaning a different casting), they do have a different rotor... I didn't mention that

Bill Gregory

OK, found the pictures....first....The 993, Big Red calipers, and Turbo 3.3/RS which use different sized rotors (304mm versus 322mm) use the same caliper adapter for a 964. The only way that the Big Reds and Turbo calipers can fit on the larger rotor is to have mounting points that are 9mm (half the distance between 304 and 322) higher than the 993 caliper.

The pictures aren't the greatest, but hopefully will illustrate this. First, the 993 caliper. This is a shot looking down the caliper, mounted in a 964, against the adaptor:



Next, a picture of a 3.3T/964 RS caliper. Note the 9mm higher 'feet' which push the caliper out to accomodate the 322mm rotor:

Bill Gregory

I did. The steps do that are documented in the aforementioned brake article, which is available here.

Bill Verburg

Ok Bill if you want to nit pic. But those are still the same basic caliper, and the same basic caliper as the 993RS/993tt rear.

Yes, there are casting and part# differences but it's still the same basic caliper and uses the same pads.

Bill Gregory

No question, it's the same basic caliper and uses the same pads. I agree the difference is subtle. However, by saying/suggesting that the 993 front caliper is the same as the 964RS/3.3T, someone else may go to the expense to buy one or the other and try to fit them, and they may not work, depending on the combination of parts they try to use.

If there are any questions on what fits or doesn't fit our non-Turbo 964's, I'd again point to the Pano article (web link above), as it provides pretty comprehensice coverage of 964 brakes and Porsche brake options for the non-Turbo 964, in addition to the more important discussion on brake dynamics.