SC Brake upgrade Question

[brett25]

Hi. Can anyone tell me if I can expect noticeable increase in breaking performance by upgrading my front rotors and calipers to the beefier Carrera parts. I would only be interested in doing it if I would be able to feel a decent improvement in stopping power.

I know this question has been asked before, but I was hoping to get a reply from someone who has gone this route and can report on the brake feel, performance increase relative to original etc. Is most of the performance gain coming from better cooling, or am I to expect better braking performance as well.

Thanks!!

[IROC]

I went from SC brakes to Carrera brakes. There really is no increase in "stopping power" in the front as the pistons are the same diameter. The fronts will manage heat better than the SC brakes due to the thicker rotors. You will notice an increase in braking "power" in the rear. When I installed Carrera brakes on my car I did not install the proportioning valve. I really work the rear brakes now. In fact, I now wear out rear pads as fast or faster than fronts. In my application it works perfectly - no lockup. YMMV.

Overall, I think the biggest performance improvement in going from SC brakes to Carrera was in heat capacity. Where I used to get a spongy pedal at the end of a track session, the pedal is now firm.

[RWebb]

hit the search button and read all comments by Bill Verburg very carefully - include the term "brake torque" in the search to narro the multitudinous threads.

the problem is that you - like almost everybody else - are proceeding on an incorrect idea of what makes the brakes wrok better -- i.e. what an "upgrade" is

this is very common

BV has two web pages with info on them but I don't think he ever laid out the concepts in brakes/upgrades there.

[theclaw]

I have stock Carrera brakes on my car. My biggest upgrade were bigger balls.... such as,

GAS...GAS...GAS...........GAS...BRAKE!TURN!

[brett25]

Thank you for the replies:

IROC,

Whats the advantage to having the rears do more of the breaking work?

Rwebb,

Thanks I will try that suggestion and see if I can get more information that way.

[JeremyD]

street or track?

Overheating issue or feel?

Bill's Page http://home.nycap.rr.com/wmv/generalbrmd.htm

[IROC]

Originally Posted by brett25

Thank you for the replies:

IROC,

Whats the advantage to having the rears do more of the breaking work?

IMHO, if you can get the rears to do more of the share of the braking task (without locking up the rear tires - which would be disastrous) then you increase the overall braking capability of the car. 911s are obviously heavier in the rear than most cars and can use the added bias of more braking in the rear. I think Carrera brakes take advantage of this rear weight bias better than SC brakes. Again, YMMV.

[Mothy]

I too found I had spongy brakes at the end of a track day when I was running standard SC brakes - the ability to brake was not an issue - I could still lock them up if I pushed too hard.

Since the rotors were due to be replaced anyway (worn too thin) and I planned to start using R-Spec tyres, I took the opportunity to upgrade at the same time.

I followed one of Bill's suggested combinations on his web page - and upgraded the front calipers to Boxter with the Carrera rotors and installed Carrera Rotors and calipers at the rear. This balances the front/rear issue mentioed by IROC without the need for the propotioning valve.

Result has been a confidence factor more than anything - I know the brakes are good enough for my needs (and some) and now don't fade at all. All up a good upgrade without breaking the bank.

Tim

[theclaw]

A simple setup to cool them helps too. I cooked mine a couple of times but after putting a cooling kit on, no worries.

[Ray B]

+1 on what Mr. Webb said. I'll paraphrase BV: "if you can skid the tires, you have enough capacity". I don't want any extra unsprung weight in my underpowered SC. I opted for some 993 air deflectors (less $$) with stock setup and have not overheated the brakes since.

[IROC]

Another point to make is that just like one needs to manage the amount of frictional load that is placed on the tires when on the track (to keep the car at the limit but not beyond) you also need to consciously manage the amount of heat going into the brakes. Proper braking technique, adequate cooling to the rotors and good fluid will go a long way to preserving your brakes without going to an "upgrade".

[brett25]

Hi thanks for all your replies. I apologize since I didn't make it clear that I seldom track this car, however I am looking to have more aggressive brakes. I have lightened the car considerably (as far as I could go short of bodywork and fiberglass). This had helped braking/handling considerably. Next, I was toying with one of the SC brake upgrade routes. Can anyone tell me what results I can expect from experimenting with different kinds of pads perhaps instead?

[RWebb]

"more aggressive brakes"

This sort of sounds like you want more initial grab (upon first pressing on the pedal). True?

IF so, I would move towards a real street oriented pad - a PO may have put combo street/track pads on there.

Find out what pads are on there now & post - if not sure, post pad description - e.g. color, etc.

Many like the Mintex pads - red box IIRC.

search on brake + pads for some opinions.

What you really want is:
1. low dust
2. good initial grab
3. consistent performance over a broad temperature range
4. low price

choose any 2....

[rusnak]

I would think of brake upgrades for a street car as fallin into two categories: 1 intial bite, and 2 heat dissipation.

I would recommend that you look at better pads to achieve the initial bite that you want. Pagid, Textar, and the ceramic PBRs all work well. Expect more dust from performance pads. There are some really nice street/race pads that cost like $500 per axle if you want to go that route.

Next if it were my car, I would want to look at additonal cooling, such as ducting the brakes with cooling air. In this category I'd also look at brake fluids with higher boiling point. These can be really expensive. A nice moderate solution is to use Ate Super Blue brake fluid.

The 3.2 911 brakes are much thicker, and unless I am mistaken you can use the Brembo rotors with 3.2 911 calipers. I dont think there is any better performance in either initial bite or heat dissipation, but if you have to have fancy rotors, the Brembos will work. I think the Carrera brake pistons are like 40mm or something like that all around. It's been awhile since I last had them apart.

[brett25]

Rwebb, thats correct. Initial grab is a more important factor to me than temperature concerns. I believe I have the Mintex, purchased from Pelican (or whatever was the OEM brand in stock at the time of purchase). I would definitely pay more $ for performance pads, if I knew what to expect from them. So are you saying that street pads are more for grab, and I assume race pads are designed for endurance and temperature needs?

Pelican sells the BHP XPS performance pads that seem like a good compromise cost vs performance. So one other question would be can I get away with putting these on just the front or all around?

[911Freak]

For what it's worth I upgraded my rotors to Zimmerman Drilled rotors (all four corners) and added PBR ceramic pads, ATE Super Blue brake fluid, stainless Steel brake lines and chucked the rubber factory ones...And 993 cooling ducts..
Overall result was very good bite on entry and minimal to zero fade on track.All with stock SC calipers..

My next upgrade will be a Brembo kit at all 4 corners, BUT I take a big hit in PCA class AX & TT..

Several guys in my PCA class run the Careera calipers/rotors, seems to be a very popular upgrade..

Seems like a cheap upgrade if your only doing street driving.. IMHO

[Ray B]

Yes , you will have more braking effectiveness with "street pads"- softer compounds- at street temps.. Save your $$. No need to buy high dollar race pads that are most effective at temps seldom (hopefully) seen in street driving. I can't imaging cooling being that much of an street issue unless you are running up and down mountains.

[RWebb]

Originally Posted by brett25

Rwebb, thats correct. Initial grab is a more important factor to me than temperature concerns. I believe I have the Mintex, purchased from Pelican (or whatever was the OEM brand in stock at the time of purchase). I would definitely pay more $ for performance pads, if I knew what to expect from them. So are you saying that street pads are more for grab, and I assume race pads are designed for endurance and temperature needs?

Pelican sells the BHP XPS performance pads that seem like a good compromise cost vs performance. So one other question would be can I get away with putting these on just the front or all around?

Yes, brake pads are like a set of crayons. They don't vary by color but by temperature (but let's just say red is for hot, blue is for cold). For street driving, you put on blue pads. Then you do some runs thru the mountains. (see above) and discover that the brakes seem to be FADING away as yo get half way down. That means the crayon is getting too hot and is starting to melt (this is an analogy, BTW). So, you can either change to a GREEN pad/crayon or duct air thru or to the rotor.

You change to Green and put in air ducts. But you notice the brakes don't bite as well when cold (initial application) - tough luck - there is no universal crayon. You are happy in the mountains and at your DE events.

Then you go to a real race class, and have the same problem. You go to RED pads. Still gt fade and pad material is smeared all over the rotor. You improve your technique; you duct in even more AIR. You look for ultra-RED but there are no such pads made. THEN is the time to put on bigger brakes. And only then.*

Yes - sometimes people will use different pad materials to try and balance out brake torque. I'd avoid that for now.

The XPS pads are very very expensive. They are supposed to be just great tho. I finally decided to shell out for them but don't have enough miles on them to tell. The claim is they extend the linear portion of the temperature range vs. mu (friction coeff.) graph (i.e. an all-weather breakfast...).


* One other situation: Your name is Bobby Bling. You don't know anything about racing but think you do. You don't understand science or engineering or brakes or cars (esp. since you dropped out of high school), but those really HUGE RED brakes look just great. You have a mental ejaculation just thinking about them. They will look so COOL especially with your Cool Collar and those boss spinner wheels that look like an iron cross. And you already added 75 hp to your Porsh with the special loud shiny muffler and magic brain carburetor kit. So you NEED the big brakes. You sniff up some glue and knock off the local Quickie Mart for the cash to get those brakes. Now you are flyin' high!