random hero
New member
I know the s2 has the same size calipers front/rear but someone has suggested to me that the front have a bigger piston is this fact or fiction ??
S2 calipers
- Thread starter random hero
- Start date
random hero
New member
The sizes you listed are also what i was told so i presume they must be right,best go and measure the pair i have for sale to see what end of the car they are for !!
Diver944
Active member
The sizes are listed on the PET parts diagrams available to download from Porsche at:
http://www.porsche.com/uk/accessoriesandservice/classic/
Peter is spot on with his sizes as listed above
http://www.porsche.com/uk/accessoriesandservice/classic/
Peter is spot on with his sizes as listed above
sawood12
New member
Not sure if the S2 had exactly the same setup as the turbo, but the early turbo front calipers had piston sizes 36mm/38mm (upto '87) then 36mm/40mm. I guess this would be the difference between the calipers with raised lettering and flat lettering. Maybe the loss of the raised lettering counteracted the extra weight of the larger pistons and extra fluid!! If that's the car then that is what I call attention to detail!
sawood12
New member
I was referring to the turbo workshop manual that states the two piston sizes as well as the medium blacks which are 36/44mm. The PET probably only states the later small calipers as the earlier small calipers were probaby discontinued. I should go into the garage and measure the calipers I removed off mine which have the raised lettering to see what they are.
Thanks Peter, Fen. The reason I ask because I am mulling over the possibility of getting an S2 race car for the Classic Sports Car Club "Future Classics" series. A brake upgrade would seem to be a reasonable improvement to aim for (and I am not restricted by the PCGB club series regs which, I think, require brakes to be standard, apart from the pads).
For info, the "Future Classics" series is mini enduro series with 30 min practice and 40 min races for 1 or 2 drivers. There's a complulsory pit stop. Cars are meant to be sports, salloons and GTs in production up to 1990. The series is good fun, the club are well run and put the competitor first and entry fees etc are not too bad compared to the BARC & BRSCC (plus the fact you can share the costs with a driving partner if you wish). There are a couple of S2's, a turbo and a couple of EMC built 2.5s that are rigistered with the series already.
For info, the "Future Classics" series is mini enduro series with 30 min practice and 40 min races for 1 or 2 drivers. There's a complulsory pit stop. Cars are meant to be sports, salloons and GTs in production up to 1990. The series is good fun, the club are well run and put the competitor first and entry fees etc are not too bad compared to the BARC & BRSCC (plus the fact you can share the costs with a driving partner if you wish). There are a couple of S2's, a turbo and a couple of EMC built 2.5s that are rigistered with the series already.
sawood12
New member
The adaptor route isn't 100% ideal but is perfectly safe and a very common mod type. You are far better off replacing the hub with the hub from a 250 turbo, but I searched high and low to find a pair when I upgraded my brakes but couldn't find them. If you can get a pair then get them - not only do they have the radial caliper mounts instead of the axial mounts, they also have larger bearings.
I also noticed the few mm of clearance between the tie rod end and the disk but there isn't much more clearance between the caliper and the inside of my 17" wheel. I guess in engineering terms a few mm is a mile.
Andy97 - just to be clear about terminology here. There are essentially three sizes of caliper. The 'small' blacks as installed on the 220 turbo's and S2's (and 968's and 964's), the medium blacks as installed on the 928S4 and 250 turbo's and the big blacks as installed on the 964 turbo, 928GT and are identical to the iconic big reds as installed on the 993 turbo.
The medium and big blacks can both be fitted to a 250 turbo hub without the need for caliper adaptors as can the calipers off the modern cars. I believe the 996/Boxster S calipers are also a very good upgrade on a 944 with less unsprung weight than the big black upgrade.
Bear in mind that on a lightened track/race car big blacks might be overkill. The medium blacks might be a better option with good cooling and decent pads and save the weight.
I also noticed the few mm of clearance between the tie rod end and the disk but there isn't much more clearance between the caliper and the inside of my 17" wheel. I guess in engineering terms a few mm is a mile.
Andy97 - just to be clear about terminology here. There are essentially three sizes of caliper. The 'small' blacks as installed on the 220 turbo's and S2's (and 968's and 964's), the medium blacks as installed on the 928S4 and 250 turbo's and the big blacks as installed on the 964 turbo, 928GT and are identical to the iconic big reds as installed on the 993 turbo.
The medium and big blacks can both be fitted to a 250 turbo hub without the need for caliper adaptors as can the calipers off the modern cars. I believe the 996/Boxster S calipers are also a very good upgrade on a 944 with less unsprung weight than the big black upgrade.
Bear in mind that on a lightened track/race car big blacks might be overkill. The medium blacks might be a better option with good cooling and decent pads and save the weight.
The back of the wheel doesn't have a bit of rubber integral to it's longevity and ultimately safety. I'm quite happy with close tolerances, but I wouldn't be happy with a hot brake disk near a rubber dust shield - and that goes double now I know the application is racing. Additionally you are adding a second set of fasteners to hold the caliper to the car.
You do indeed pay your money and take your choice, but using adaptors is a compromise in anyone's book and one of the areas I wouldn't compromise in is braking.
The right way to do the job is to source hubs from a 250 Turbo - more expensive, sure. "On the cheap" and brakes - up to you.
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