SC Brake Upgrade ??

xpensivewino · 04-20-2006, 09:40 AM

I am looking for some brake upgrade combinations for my SC that require minimal machining, on a medium budget. I am running 15" wheels. The obvious is 78-79 turbo brakes with full floating set up, but this is not cost effective at this time. I was wondering if anyone has done early 944 turbo calipers on Carrera rotors up front, is this a bolt up?? Also I have heard of 964 4 piston rears and a Carrera rotor on the front of SC's. Lastly would be the 917 style calipers with later non-floating discs?? Will this work ?? Any advise would be greatly appreciated.

Jim Smolka · 04-20-2006, 10:23 AM

One of the simplest upgrades is to install Carrera 84-89 calipers and rotors. The calipers bolt up and they are wider as to fit the wider rotors. The rear calipers have bigger pistons, so a Carrera proportioning valve may be a good idea.

edward993 · 04-20-2006, 10:39 AM

OK, who's got that link. C'mon, you all know the one I'm talking about. Was it Bill V.'s??

xw,
this is what you need to see. It details the options for you in order of cost and effectiveness. Try a search.

Edward

Bill Verburg · Bill Verburg's Garage

You mean this one?

edward993 · 04-21-2006, 07:54 AM

Well I didn't post the question, but thanks, Bill! I can't tell you how often I've seen posts or references to your excellent write up. You are a real asset to the Porsche community.

Edward

randywebb · 04-21-2006, 09:55 AM

Everyone should send Bill a beer ...

PorscheGuy79 · PorscheGuy79's Garage

I just did this myself, no trouble at all.

Size does matter. (my SC to Carrera brake upgrade)

Vipergrün · 04-21-2006, 11:32 AM

Installing Boxster calipers and Carrera rotors front and rear is a nice setup. However, some will argue the value of going with the Boxster over the Carrera calipers. I have the Boxster setup on my SC -> 73RS Replica and it's nice and balanced.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally posted by bb80sc
Installing Boxster calipers and Carrera rotors front and rear is a nice setup. However, some will argue the value of going with the Boxster over the Carrera calipers. I have the Boxster setup on my SC -> 73RS Replica and it's nice and balanced.

There is nothing wrong w/ it, it is an improvement. It's just that you can get the same bang for a lot fewer bucks w/ Carrera front calipers and rotors and leave the rears alone.

I don't know if anyone else has noticed but a lot of the folks here are umm... frugle

PorscheGuy79 · PorscheGuy79's Garage

My dad has the Boxster/Carrera set up and finds it well balanced and loads of breaking power.

euro911sc · euro911sc's Garage

Took me a few hours at most and I had Carreras F&R. Works very well and I have no prop valve.

-michael

Vipergrün · 04-21-2006, 08:13 PM

Quote:

Originally posted by Bill Verburg
There is nothing wrong w/ it, it is an improvement. It's just that you can get the same bang for a lot fewer bucks w/ Carrera front calipers and rotors and leave the rears alone.

I don't know if anyone else has noticed but a lot of the folks here are umm... frugle

I was under the impression that being able to see the "Porsche" script on the calipers would add 10 HP

In all seriousness, I basically stole the front setup, so it did not hit the pocketbook nearly as bad for the rears.

Would you see any benefit adding a proportioning valve with the Boxster setup? I have not had her on the track yet, but she feels balanced on the street. I fear the rears may prematurally lock on the track, though....

Peter Bull · Peter Bull's Garage

Sorry for barging in like this, but there is one issue that does not seem to be discussed when upgrading brakes. That is brake pad size versus pedal response.

How does this sound? If you add the same amount of force on a big and a small brake pad, the small pad will compress more because the surface pressure (force/pad area) is higher. Since the small pad deforms more than the big pad, the brake pedal will feel more spungy with small pads.

With that in mind e.g. the Boxter caliper upgrade will give a firmer pedal response which gives a better sense of control compared to using a Carrera calipper which has the same brake pads as the SC.

Or am I totally off?

Jim Smolka · 04-22-2006, 03:07 AM

Another factor to consider for track applications is pad cost / life of the pad. Carrera calipers are good, but hard track uses wears out a set of quality pads in a few track days. For this reason on the 3.6 SC, I went with a modified set of 'Outlaw' 4 piston calipers. The plan is to get about 12 to 20 track days on a set of pads.

Bill Verburg · Bill Verburg's Garage

Quote:

Would you see any benefit adding a proportioning valve with the Boxster setup? I have not had her on the track yet, but she feels balanced on the street. I fear the rears may prematurally lock on the track, though....

No, stock Boxsters front and rear are a tad front biased but nothing extreme, you will just go through front pads a little faster than rears.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally posted by Peter Bull
Sorry for barging in like this, but there is one issue that does not seem to be discussed when upgrading brakes. That is brake pad size versus pedal response.

How does this sound? If you add the same amount of force on a big and a small brake pad, the small pad will compress more because the surface pressure (force/pad area) is higher. Since the small pad deforms more than the big pad, the brake pedal will feel more spungy with small pads.

With that in mind e.g. the Boxter caliper upgrade will give a firmer pedal response which gives a better sense of control compared to using a Carrera calipper which has the same brake pads as the SC.

Or am I totally off?

You are totaly off, while the stiffness of all of the mechanical components can affect brake feel, In 911s it is generally not an issue or at worst a very minor one and pad compression has the least contribution in that regard.

Pedal feel in a Porsche is almost entirely a function of the master to slave ratio.

Wangrande · 04-22-2006, 06:26 AM

Is the 17mm master cylinder of the earlier cars good enough or is a 19mm required? I have done the Carrera front/rear upgrade but have not finished the project yet. Thanks to this post I now know I need the p/v! I am pretty sure my 72 has a 17mm master. I have searched, but found no specifics. Any advice greatly appreciated.

Vipergrün · 04-22-2006, 06:27 AM

Quote:

Originally posted by Bill Verburg
No, stock Boxsters front and rear are a tad front biased but nothing extreme, you will just go through front pads a little faster than rears.

Thanks Bill.....and sorry to the original poster for the hijack, hopefully it was helpful

Bill Verburg · Bill Verburg's Garage

Quote:

Originally posted by Wangrande
Is the 17mm master cylinder of the earlier cars good enough or is a 19mm required? I have done the Carrera front/rear upgrade but have not finished the project yet. Thanks to this post I now know I need the p/v! I am pretty sure my 72 has a 17mm master. I have searched, but found no specifics. Any advice greatly appreciated.

Your '72 certainly came w/ a 19.05mm m/c.

For Carrera f/r brakes that will work fine, A slightly better m/c would be a 20.5mm m/c 901.355.012.04(ATE# 3.2120-3901.3).

They are not easy to come by

Peter Bull · Peter Bull's Garage

Quote:

Originally posted by Bill Verburg
You are totaly off,

Hmm, too bad. After having rebuilt the calipers, changed to steel braided brake hoses and being told by the local Porsche workshop that "oh no, an old master cylinder does not make the brakes feel spongy", I was kind of hoping that was the answer to the spongy pedal in my car.

Any suggestions?