Brads911sc

What are the main differences between the SC and Carrera brake setup? I have no complaints about my SC brakes... I dont track my car... but Im always looking for tweaks to make it better.

Todsimpson

944 turbo brakes (also 964) can be put on an SC by writing a big fat check to VCI. They will cut the mounting ears off, and sell you custom adapters to mount to your stock brake mounts. The kit uses 944 turbo front rotors (28mm) and Carrera rear (24mm) rotors. The front hubs need to be spaced out slighty with an included spacer and you will also need to upgrade to a 23mm master cylinder.

It's actually a nice setup but the bang for the buck is low because the machining costs are so high.

Carrera rotors are 24mm front and rear compared to 20mm on the SC, which means better resistance to heat. The bias changed as well, Carrera brakes use a larger piston in the rear so during normal braking the rears are doing more of the work. To prevent lock up during heavy braking a proportioning valve was added to the rear of the Carrera.

If you want SC brakes to work at the track, they can, check in with the PCA D class guys who have to run stock brakes. As you go faster, you use the brakes less. Really!

911vet

Hey Ernie, I don't know what the going rate is on 944T brakes, but there's a set for sale on Pelican. I'll PM you with some info. But from what a lot of people say, you might want to look at Carrera calipers too???

DaveConn

Back to the OP's original questions, I think there needs to be a clarification about WHAT one achieves by swapping the various rotor/caliper combinations.

That is, many folks in the past have confused the issues surrounding what you get when you put bigger rotors and calipers on a given car; are you wanting to reduce the propensity for fade (i.e., increase thermal capacity), or do you literally want to stop faster (i.e., shorten the braking distance). Choosing one (or both) CAN have a very different set of answers, in terms of the parts/work needed. BTDT

Not that I want to turn this into a Steve Weiner Love Fest (not that there's anything wrong with that... ), but IMHO he is THE man for considering WHO you are and WHAT you want to do. I would STRONGLY suggest that anyone about to spend hundreds, or thousands, of dollars on brake changes/upgrades pick up the phone and call someone with experience, whether it's Steve, Geoffrey Ring, TRG, etc. No offense to anyone on Rennlist, but simply relying on what you read here, especially when it comes to your car's ability to stop, seems damn close to playing Russian Roulette.

Sorry for the rant.

Dave

911S3.6

Amen Dave.
Well put.
Gotta pay to play, or else go sit in your car and make zoom-zoom noises....
Amateur opinions are just that...opinions.
Rennlist is fortunate to have folks like Steve, Geoffrey, etc... that have the working knowledge and experience they are willing to GIVE to all of us. (and hopefully drum up some business too)
It is key for the members not to denigrate this service with gibberish and self-proclamation.

911vet

Yeah, if it wasn't for Rennlist, I'd have no place to speak endlessly about things I know almost nothing about. Heck, all I have to do is install one set of Bilstein HDs and I'm an expert on suspension upgrades. Do a valve adjustment (once) and I'm licensed to give advice to all those "newbies" out there. I've done two DE events and if you ask me the best line around Mid Ohio -- I'll gladly tell you

Hug hug.

911vet

Your question may have been rhetorical, but I'm gonna answer 'cause it's probably a better question than my thread starter.

I have experienced a little brake fade on the track. Not enough (yet) to be of concern. And I would guess that different pads alone might resolve that. I'm running cheap OE style --- I got them prior to DE and I never liked the poor cold-braking power that some anti-fade compounds offer.

But, now, I'll trade the lack of cold-stopping power for less fade.

So.... while less fade is always better, my real goal is to stop faster.
So I can live by the racer's motto: To go faster, you have to stop faster.

DaveConn

Hi Shannon,

I was in the same boat a year ago, and for me anyway, it was an expensive endeavor, but MAN do I have some brakes now! I'm not sure what it will take with your car, but I'd be VERY careful about assuming larger calipers and rotors, alone, will get you there.

As a side note, along with appropriate pads make sure you are using a really good brake fluid!

Dave

g-50cab

I logged on here today for the first time in months for two reasons. #1 to comment on this thread and #2 to look at Ed Hughes track prep pictures.

Shannon - I am glad you are having fun at the track. Great fun isn't it?

Brakes. Great when they work - a little un-nerving when they fade or don't work at 100% on the track.

As the great Steve Weiner eluded to; many factors can contribute to brake issues. Combinations of wheel and tire width, vehicle weight, horsepower, Tire composition, cooling, brake fluid, brake pads, driving style, ambient temperature and track layout can all play a part.

The frustrating part of being a newer driver is learning to drive with less braking, or if you are braking on the brakes hard then off quickly.

Anyway - to get to my point. You are driving a heavier car (convertible) with higher HP (the later Carreras can scoot). Depending on some of the other factors listed above - you may be at the marginal edge of Carrera brake performance.

Before investing big money in a brake upgrade - and they really are tough to do real cheap = I'd invest in ; better fluid (Motul RBF 600 is a step ahead of ATE Blue, but better yet, Castrol SRF is even $$ better) I'd be sure and invest in some solid RACE brake pads. They will sound like a school bus on the street, but easy enough to change out, AND I would invest in some under A-arm cooling ducts (like AJ USA or Pelican Sells).

Try that out first - if you still have issues, your next option is removing weight (which can be tough to do too much with a cabriolet, I'm not willing at this point) or pony up for some bigger brakes (which really means bigger rotors with more heat sink abilities, calipers look pretty but the rotors are the ones doing all the work.

Anyway - I have been there done that - I drive a 1987 Carrera Cabriolet at the track - I have come down to turn 10 at Sebring doing 110 and had my foot go to the floor (and may never be able to get that crease out of the seat ). I have had major brake issues including but not limited to going through a set of pads in a day at the track, replacing dirt seals after every day at the track and coming home from the track with metal to metal contact, using my hand brake to help slow me down.

Probably one of the best resources I found for brakes is Bill Verburg

http://www.pelicanparts.com/MotorCity/wmv/brakes.htm

911vet

Wow, I feel honored! And I appreciate that you chose to share so much great information with me. Now... make it a habit, ok?

I wish I had started about 20 years ago. It is fantastic. If/when I can get a dedicated track car, I will. But for now, I'm out to prove that a Cabriolet can wupp up on the best of them.

To be honest, I haven't experienced any bad moments yet. I have worked on being smooth. I guess I recognize how competitive I am (wait, DE isnt a race is it?) I will quickly outgrow what I've got. And when the track tires go on and the speed goes up I want to balance it with anti-speed.

That's my first priority. Suggestions? I was thinking a set of Porterfields for the track and then switching back to a second set of Porterfields for the street. My last DE instructor recommended that... his thinking was rotors like having similar compounds for race and street if you're going to switch pads.

My instructor recommended that too. I guess I can't keep ignoring all this great advice. Will do.

My A/C works but I never use it. I left it on for potential resale. But I can always re-install it later. So perhaps I will take out the AC. I'm switching to Pole Position seats soon (does that shave some weight?). I'm not ready to strip the carpet as this will remain my street car too. So I'm limited on removing weight.

Man... I WANT that track car!!!!!

That's music to my ears. I want to know what that feels like.

911vet

So, Dave, dare I ask what your solution was?

g-50cab

I too wish I had started this 20 years ago... Who knew? Always satisfying to get the point by

Track tires can make a huge difference. Street tires are always better to learn on. They communicate more.

I have been using Porterfield R4s for the street and R4 for the track. I been very happy with them.

Easy and pretty cheap -

Yes the stock seats are heavy - AC also has some weight - but as you said - resale could be an issue.

I'd try the fluid, the porterfield r4 pads and the AJ scoops. Try that first and see how it goes.

911vet

May I ask what size wheels you are running?
I'm searching for a set of track wheels (I think I'll stay with Fuchs). I'm torn between stock 16x6/7 or going up to 16x7/8. It doesn't seem there's much difference in tire selection. I don't think I want to jump up to 17" yet.

Thoughts on this? Seems like staying with the smaller keeps my cost and unsprung weight down a little bit. But I realize I give up patch size.

By the way, will any 16" Fuch off an SC or Carrera have the correct offset?

Your Porterfield recommendation is the same as what another track dude told me. So I'm going with it

old man neri

Nien!!!!!. One of the biggest myths around. Patch size is affected by only two things essentially. The weight placed on the tire and the air pressure. The width of the tire will determine the patch shape. Always concentrate on getting better, stickier, grippier tires than getting wider tires.

Sorry...just my 0.02.

911vet

Ich bin konfus (I am confused). You are saying I won't gain patch size if I go with 16x7 and 16x8 versus the OE 16x6 and 16x7 ???