Carrera rotors on a SC

OOH-911 · 02-17-2005, 02:50 AM

Hello all

I have searched previous threads without much success so I apolagise in advance if the question has been asked more than once before. I have a '79SC that has stock brakes with the original rotors that are just about worn out. I want to upgrade to Boxter monoblocks at a later date when the finances permit. My question is this:

If I have to buy new rotors rather than buying the 20mm SC units I would like to upgrade to 24mm 3.2 Carrera units and use these in the future with the Boxter brakes. The A calipers that I have now will be to narrow to accommodate the wider discs and pads. Do I have to purchase the wider Carrera calipers second hand or can I buy a spacer that can go between the two caliper halves on my current SC calipers to give the extra clearance.

Hope you guys can help with my querie

Todd

Bill Verburg · Bill Verburg's Garage

Quote:

Do I have to purchase the wider Carrera calipers

Yes, and you will find that is all you need. The Boxster calipers are mostly appearance items, the heart of the upgrade is the Carrera rotors.

OOH-911 · 02-17-2005, 03:10 AM

Bill

Does that go for both front and rear that I will have to buy the second hand rotors. I have read that you can buy a spacer for the rear caliper but am unsure whether this is true or not.

Thanks for the quick reply

Todd

OOH-911 · 02-17-2005, 03:11 AM

I meant to say second hand calipers not rotors in the previous post.

Sorry

ljp911 · 02-17-2005, 04:17 AM

If you want to upgrade the rear to the carrera calipers, you will need to find a pair, either new, rebuilt or used. Carrera rear calipers have slightly larger pistons which will give you increased rear bias. Depending on your suspension and tire choice, you may find that you need a proportioning valve added to the rear circuit. The carrera caliper also has a wider throat to accomodate the thicker rotor. That may be the space you are referring to. If you split the caliper to install the spacer, you will still not be able to put the larger pistons in there.

Todd Simpson · 02-17-2005, 04:35 AM

Use carrera rotors and calipers on the front and your stock brakes on the rear. No proportioning valve needed and bias remains the same as what you have now.

The carrera upgrade is not needed in the rear, the fronts still do the majority of the work. You'll have a 24mm rotor in the front and 20mm in the rear. Take a look at 930 (32mm and 28mm) and 964 (28mm and 24mm) and you can see Porsche has often put thicker rotors on the front.

The Carrera front is the most common brake upgrade and lots of us here use it.

Bill Verburg · Bill Verburg's Garage

Like Todd said use the Carrera caliper and rotors on the front and leave the rears alone. no p/v, std m/c

UNLESS

You go ahead and do the boxster front calipers, in which case you do want Carrera rear calipers and rotors, no p/v, std m/c

like ljp911 said the Carrera rear pistons are bigger than stock and will move bias to the back, if used w/ Carrera fronts you do need a p/v and even then it's not an ideal solution.

At one time the spaceers and seals and bolts were availble separately, then came the lawyers and liability so alas they are NLA.

I would buy new rotors as they are cheap, calipers do due diligence when buying used.

OOH-911 · 02-17-2005, 11:46 PM

Thanks Bill and everybody for the informative replies. I will take the advice and go with thw Carrera front calipers and rotors and leave the rears stock. Thanks once again.

Todd

KobaltBlau · 02-18-2005, 06:57 AM

If you find new carrera calipers make sure that the two halves are not taken apart currently. the seals on the sides of the spacer and the through-bolts are not easy to get if they need replacement, though the normal rebuild parts such as bore seals and even complete pistons are no problem.

In my opinion:
Keep in mind that for street use the SC brakes are just fine.

for track use a good brake cooling duct system can make a huge difference. The stock class SC racers are dang fast with SC brakes (and good brake cooling!)

carrera rotors are a bit more expensive (not much) but definitely heavier. which is fine if you still need them with brake cooling.

I realize your current ones are worn out so you may still want to do this.