Brakes: 996 vs 993 calipers

[smdubovsky]

Jpnovak asked me about 996 vs 993 calipers in a thread I started about adapters:
Brakes: 993 to 911 caliper adapter dimensions?

Instead of putting the info there, I thought it might be nice to start a new thread. All pics read from Left to Right. (BTW, its a 6" ruler in some of the pics)

996R, 996F, 993F, 993R


The 993F throat is 34.72mm (to clear the 32mm rotor).



The 996F throat is 30.65mm (28mm rotor)



The specific question jpnovak asked is if the caliper could be modified to fit the same 930 rotor that the 993 caliper can use. There is a small problem of the throat shape. The 996 monoblock has an arched throat. Here is a pic w/ the calipers set to 34mm (2mm wider than a 930 rotor). You can see it JUST starts to intrude on the arch. I think it would clear (because the caliper would have some amount of radial clearance when mounted), but I don't have a 930F rotor to test w/.



FWIW, the room for pads in the 996F is almost exactly the same as the 993F. Meaning, if the pistons are pushed all the way into the caliper, there is the same distance from the piston to the end of the "pin" near the rotor. If you shave 1+mm off the 996F pins to clear a wider rotor, you might also need to shave a little off the pads. (I don't have a new pad of either to know the thickness).

I can also weigh these if anyone is interested...

I'll do the same pics for the rears later.

Enjoy,
SMD

[Bill Verburg]

Here is a f/r 993 RS set

rear on left front on right


throats are 34.5mm and 30.7mm respectively

the 996 set is the same as the Boxster S

the 993RS rear is the same size as the 993 front

[smdubovsky]

Thanks Bill, is there anyway to tell which 993 rears I have from the exposed piston ends? They don't match up w/ anything on your chart and I REALLY don't want to have to pull the dust boots off to find out what the real diameters are FWIW, the exposed pistons are 30.5/26.5mm (measured behind the small chamfer). Could these be the 30/28 ones you call "basic 964 rear" from a 993C4 or are the parts of the pistons behind the boots a COMPLETELY different size? I know they aren't S4 rears because they use a 98mm wide pad.
Tnx,
SMD

[smdubovsky]

Fronts part2:

I went rooting around the cold garage and found some rotors. Turns out I *DO* have a 930F rotor and all 4 996 rotors. Here is a pic of a late 930F (left) and a 996F (right) rotor. I put a 996F pad on the 930 rotor.



Closeup:



You can see that the 996 uses a much taller pad and hangs over the 930 rotor. So, you can NOT use a 996F caliper on a 930 rotor. It will require some other rotor and hat.

SMD

[Bill Verburg]

993rear, 964rear(4piston), 928 S4 and 928GTS rear are all basicly the same caliper.

the 993r has bigger 30/34 pistons vs the others 28/30

if the exposed part is 30.5/26.5mm then they are 30/34 993 rears

if the pads were included w/ the calipers and the antisqueal shims were still on them, the shims will have the size clearly imprinted

left to right 993tt/RS front 993tt/RS rear, 993rear antisqueal shims

[Bill Verburg]

the 996 front rotor is 318x28 the rear is 299x24

[Bill Verburg]

Here is a 993front and a 993tt front

the o/s of these 2 are the same, 70mm from inner mounting face to back rotor face

[Bill Verburg]

993 is 304x32 993RS/tt is 322x32

[smdubovsky]

if the pads were included w/ the cakipers and the antisqueal shims were still on them, the shims will have the size clearly imprinted

Now, THATS something cool to know. Sure enough, went and cleaned up the used pads and there is a 30 & 34 printed on the shims, so they must be 993C2 rears. You are the man Bill

BTW, the 996F rotor offset (inner mounting face to back rotor face) is 61mm.

SMD

[Bill Verburg]

I sure am a lousy typist though

[smdubovsky]

Bill, Don't worry about the typing, I suck too No one ever qoutes me, so I can edit it in time...

Could you measure the radial dimension of the swept part of both the 993 and 993tt rotor? Im curious if the 996 caliper pad wouldn't hang off one of them (IF if was modified for a wider throat). I know Steve Timmons machines a little off some sort of porsche hub and can fit the 993tt rotors on a 911. A custom hat for the 993tt rotor is probably easier.

The 996F rotor is ~62mm.

SMD

[Bill Verburg]

Could you measure the radial dimension of the swept part of both the 993 and 993tt rotor?

54 and 64mm respectively.

The 993 and 993Rs/tt are the same caliper except the RS/tt is 10mm taller.