track car brakes

[r lane]

I have a narrow body 3.0 track car with 930 brakes and a 23mm master cylinder non boosted. Despite needing a lot of leg, the brakes definitely do the job. I am building a wide body car with a 3.6 engine and felt that I should go with something larger in the brake department than what I have on the narrow car. I had a set of 996tt calipers that I considered, but due to my calculations and response from this site, it appears they would not be a well balanced package for this car. At present I have those calipers on the car with 13'' discs but am in the market for a different caliper that is better matched. Big Reds come in many flavors it appears. Would appreciate hearing from any of you that have been down this road or something similar. Thanks, Bob

[Bill Verburg]

Originally Posted by r lane

I have a narrow body 3.0 track car with 930 brakes and a 23mm master cylinder non boosted. Despite needing a lot of leg, the brakes definitely do the job. I am building a wide body car with a 3.6 engine and felt that I should go with something larger in the brake department than what I have on the narrow car. I had a set of 996tt calipers that I considered, but due to my calculations and response from this site, it appears they would not be a well balanced package for this car. At present I have those calipers on the car with 13'' discs but am in the market for a different caliper that is better matched. Big Reds come in many flavors it appears. Would appreciate hearing from any of you that have been down this road or something similar. Thanks, Bob

The 930 brakes will likely be adequate for the 3.6

next step up from there would be 993RS which are a version of 'Big Red'

all the fronts are the same except for color, pistons are 36/44, 993 and 964 3.6t versions are red, 928 GTS versions are black w/ reversed bleeds and feed all use 322x32mm rotors, all the 993 versions of the rotor are the same 2 piece hat/annulus design, the 964 versions are 1 piece and the 928GTS versions are also 1 piece but also not drilled

in back 964 3.6t versions have smaller calipers and rotors, all the 993 versions use the bigger S4 sized caliper in red, on 322x28 rotors. The 993RS versions are 30/36 the 993tt versions are 28/28,

Best setup w/ these is the 993RS version

there are pluses to going to a 330mm rotor w/ these calipers though some hoops need to be addressed, biggest plus is at 330mm the rears can also be 2 piece

biggest issue w/ 993RS on a 911 is in back where major work is needed on both the rotors and calipers to use them, bolt on versions of the 9933RS for use on 911 used to be available from Race Technology which is the N. American arm of Brembo, but as far as I know they have stopped selling them

[winders]

Originally Posted by r lane

I have a narrow body 3.0 track car with 930 brakes and a 23mm master cylinder non boosted. Despite needing a lot of leg, the brakes definitely do the job. I am building a wide body car with a 3.6 engine and felt that I should go with something larger in the brake department than what I have on the narrow car. I had a set of 996tt calipers that I considered, but due to my calculations and response from this site, it appears they would not be a well balanced package for this car. At present I have those calipers on the car with 13'' discs but am in the market for a different caliper that is better matched. Big Reds come in many flavors it appears. Would appreciate hearing from any of you that have been down this road or something similar. Thanks, Bob

How much is the car going to weigh?

I have a PCA GT3 race car with a 369 HP/290 Ft-lbs torque at the wheels. The car weighs 2000 lbs without driver or CoolShirt setup. In "start of the race" trim with fuel and CoolShirt installed, the car weighs about 2300 lbs. The car has a Tilton pedal assembly with dual master cylinders and 930 rear brake calipers front and rear. I use PFC 11 compound pads. I run 11.75" x 1.25" rotors at the front and stock 930 rotors at the rear. I use Brembo HTC-64 brake fluid.

The car is wicked fast and brakes are NEVER an issue.

Unless you car is really heavy or you use crappy brake fluid, using Big Reds is just going to add weight and not get you better braking.

[Evan Fullerton]

Yes, as Bill mentioned, Race Technology/Brembo have stopped selling the 993RS/ 993TT rear rotor with the parking brake bell bolted on for use on a 911. It’s a pretty simple part/modification though to adapt the rotor though is you have access to a machine shop.

The Race Technology Rear GTP kit that came with these rotors use a Lotus Esprit front caliper and a adapter bracket to suit. Bias with 993TT big reds up front is quite rearward though as the Lotus calipers are 36/40 piston size. Race Technology sold then for use with F50 Ferrari front calipers which look like 993TT Big Reds but have 40/44 pistons and a 356mm disk.

Some time later, probably when they stopped wanting to modify the rotors, Race Technology started selling a rear kit that uses 360 Ferrari rear calipers with 28/30 pistons on 930 disks. This bias with 993TT fronts is a bit too much front bias and leaves something on the table.

993RS all around is the best bias setup from what I found if you don’t go for F50 Ferrari fronts and don’t want to run dual master brakes with a balance bar or an adjustable bias valve on a single master setup.

[Bill Verburg]

Originally Posted by winders

....

Unless you car is really heavy or you use crappy brake fluid, using Big Reds is just going to add weight and not get you better braking.

If you need it and can use it(again not likely) then the above is not true

993RS Big Red provide a larger thermal reserve and more brake torque 1962/1242 N-M vs 2306/1618 N-M,

Whether you need it for thermal properties depends on the drivers technique, car weight, car speed and pad/fluid specifics

Whether you can use it depends on tire grip levels

[Evan Fullerton]

Originally Posted by winders

How much is the car going to weigh?

Unless you car is really heavy or you use crappy brake fluid, using Big Reds is just going to add weight and not get you better braking.

While 930 brakes probably are enough for most. Street car with passenger gets things up to ~3000lb. If the car will be driven at all spiritedly in a hilly area like the LA Mountains, that’s a harsher environment on brakes then a light car with moderate power and HUGE cornering capability on the race track.

We all know your car is perfect but there are other use cases.

[winders]

Originally Posted by Evan Fullerton

While 930 brakes probably are enough for most. Street car with passenger gets things up to ~3000lb. If the car will be driven at all spiritedly in a hilly area like the LA Mountains, that’s a harsher environment on brakes then a light car with moderate power and HUGE cornering capability on the race track.

We all know your car is perfect but there are other use cases.

Look at the original post. It specifically states "track car". So I answered the question based on it being a "track car". Weight is an issue which is exactly why I asked how much the car weighed AND is why I put the weight caveat in my last sentence....

My car isn't perfect...I am doing stuff to make it better over the winter....and I addressed the use case presented by the OP. He didn't say it was a ~3000 lbs street car driven hard in the hills and mountains around L.A. with a passenger.

Jeez....

[r lane]

Great info fellows. I actually have a set of front big reds. they need repair as in needing sleeves. Who can do that repair. That is the direction into which I think I will head. Then source a set of rear 993 RS or facsimile. Will install a dual master cylinder setup as well. My narrow car weighs 2450lbs with a half tank of gas and no driver, which is probably what it weighed when it arrived here from Deuseldorf in 1978. You remove front and back seats, carpet, swap metal bumpers, sunroof panel and rear lid for fiberglass, add a cage, heavy rear turbo arms, front suspension brace, fuel cell cage and it is a wash. The new car I assume will be about the same. Don;t know how you guys get them down to 2000lbs withour replacing fenders, doors and roof.

[chrismorse]

Give Eric at PMB a call

[ted]

Perhaps try some Project Mu pads in whatever calipers you pick.
https://www.vividracing.com/project-mu-m-114.html

[wildcat077]

I have 996TT brakes on my 89 911 ... i tracked it for 7-8 years with PCA and the brakes are overkill for the car.Second thing is you would have way too much front bias and you would require a dual master setup , but then forget about street drives.I also have a 95 3.6 in my car , so yes it's fun outbraking GT3's on track but 930 brakes are well balanced and would do the job just fine.I have a brand new never installed lightweight fiberglass front trunk that i don't plan on using if you're interested.

[Bill Verburg]

Originally Posted by r lane

Great info fellows. I actually have a set of front big reds. they need repair as in needing sleeves. Who can do that repair. That is the direction into which I think I will head. Then source a set of rear 993 RS or facsimile. Will install a dual master cylinder setup as well. My narrow car weighs 2450lbs with a half tank of gas and no driver, which is probably what it weighed when it arrived here from Deuseldorf in 1978. You remove front and back seats, carpet, swap metal bumpers, sunroof panel and rear lid for fiberglass, add a cage, heavy rear turbo arms, front suspension brace, fuel cell cage and it is a wash. The new car I assume will be about the same. Don;t know how you guys get them down to 2000lbs withour replacing fenders, doors and roof.

Modifying the 993RS calipers for use on a 911 is not trivial, same for the rotors

These are stock 993 tt and RS calipers, tt on left, RS on right. The only difference is the piston sizes, tt are 28/28, RS are 30/36



From left stock 993RS rear, axial mount, 993RS rear modified for 911 rear use, radial mount after machining w/ a caliper adaptor, stock 993RS/tt front, axial mount




This is a 993 RS/tt rear rotor modified for use on a 911. The whole center 993 section is cut out and a 911 center pinned in, in essence a 2 piece assembly as used in front, this retains the parking brake



A possible alternative that I haven't tried but see no reason it wouldn't work is to uses a stock 930 309x28 rear rotor and a front 993 caliper. The front regular 993 caliper though black is the same as the rear 993 RS caliper but is axial mount stock. Just have the 36/44 pistons sleeved down to 30/34 or 30/36, I've had White Post Restorations sleeve down other alloy calipers though not that much.

An other alternative that I have used is is a regular 30/34 993 rear caliper on a 930 rear rotor. Some pretty easy mods make this possible



Here is a stock 964/993 rear caliper, 964 version is 28/30, 993 version is 30/34 there are also some small visual differences. Just plug the stock axial mount holes and redrilled to accommodate the 930 rotor and slightly clearance the throat are. Both have been done to this one


another better rear alternative is a 964 t rear caliper( these are available in red and black, pistons are 30/34 the caliper is a wider version of the 993 rear so only the axial mount mod is necessary.

[Jamminman]

Newbie to Porsches. I'm familiar with the 930 brake upgrade and the 993RS Big Red upgrade. The former seems very doable and the latter a lot of work, but still doable. The latter also adds a lot of unsprung weight and the brake bias issue. I have two questions:

1. Any thoughts on the Elephant Racing "930" brake setup? Seems like a similar option to the 930 with a slightly better caliper and lighter. Maybe a better overall setup? I recently talked with someone at TPC racing who felt in a track car that is under 2600lb even the boxster brakes were adequate.

2. Does anyone make slotted rotors for the 911 brakes? Drilled rotors are prone to cracking, especially in track applications.

Thanks!

[Bill Verburg]

Originally Posted by Jamminman

Newbie to Porsches. I'm familiar with the 930 brake upgrade and the 993RS Big Red upgrade. The former seems very doable and the latter a lot of work, but still doable. The latter also adds a lot of unsprung weight and the brake bias issue. I have two questions:

1. Any thoughts on the Elephant Racing "930" brake setup? Seems like a similar option to the 930 with a slightly better caliper and lighter. Maybe a better overall setup? I recently talked with someone at TPC racing who felt in a track car that is under 2600lb even the boxster brakes were adequate.

2. Does anyone make slotted rotors for the 911 brakes? Drilled rotors are prone to cracking, especially in track applications.

Thanks!

For a 911 the best currently available bolt on set of more effective brakes is the Elephant Racing version of 930s, Hands down, no ifs ands or buts

Boxster brakes on stock 911 rotors is no improvement in performance
Boxster on Boxster is a small improvement
Boxster S on Boxster S is also nice but not any where as good as the Elephant 930s

There are slotted 930s rotors available for the front but I've never seen them for the back, front is where it's most critical to avoid cracking

[JeremyD]

I tracked a 1974 wide body with 245/315 sticky tires and a Mike Bruns 3.6 - At Sebring - which is tough on brakes = I had 993 or S2 fronts and 964 turbo rears with 930 rear rotors and custom hats/rotors for the 993's to work. Never had an issue over 6-7 years with brakes after that.

[Bill Verburg]

Originally Posted by JeremyD

I tracked a 1974 wide body with 245/315 sticky tires and a Mike Bruns 3.6 - At Sebring - which is tough on brakes = I had 993 or S2 fronts and 964 turbo rears with 930 rear rotors and custom hats/rotors for the 993's to work. Never had an issue over 6-7 years with brakes after that.

Very nice car!

The heart of a track oriented brake setup is primarily the rotors and secondarily the supporting structure that keeps the rotor temps down

JJD's setup here has at it's heart 930 rotors, 32x304 front and 28x309 rear, the better the rotors the less support they need. Support is things like cooling, fluid, pads and weight loss

930 calipers on 930 rotors generate 1961/1242 n-M of torque @70bar line pressure
993 on 930 generate 1968/1162

to get get more torque bigger rotors are needed, 993RS 32x322 and 28x322 generate 2306/1618 N-M w/ 993RS calipers, again @70bar line pressure


go crazy and put 997GT3 gen 2 calipers on matching 34x380 and 28x350 rotors and you can generate 3263/2002 N--M

the problem w/ big brake torque is that you need sticky tries and lots of normal force to utilize it

For normal 911s w/ up to ~325 hp and less than ~3k # 930s are going to provide more than sufficient torque and thermal capacity especially w/ good supporting structure

[winders]

Originally Posted by Bill Verburg

For normal 911s w/ up to ~325 hp and less than ~3k # 930s are going to provide more than sufficient torque and thermal capacity especially w/ good supporting structure

The 930 brakes work great on 430HP/2000 lbs race 911 cars as well….

I have never had a braking problem with 930 brakes!

[Bill Verburg]

Originally Posted by winders

The 930 brakes work great on 430HP/2000 lbs race 911 cars as well….

I have never had a braking problem with 930 brakes!

Never even hinted that you would, its all about KE management, .5MVV and heat management, all that KE has to go somewhere and the temperature rise during that process has to be w/i the systems capability

more mass wants more brake

more speed wants more brake

shorter recovery time wants more brake

more speed wants less brake

[Jamminman]

Originally Posted by Bill Verburg

For a 911 the best currently available bolt on set of more effective brakes is the Elephant Racing version of 930s, Hands down, no ifs ands or buts

Boxster brakes on stock 911 rotors is no improvement in performance
Boxster on Boxster is a small improvement
Boxster S on Boxster S is also nice but not any where as good as the Elephant 930s

There are slotted 930s rotors available for the front but I've never seen them for the back, front is where it's most critical to avoid cracking

That's great info. Thanks!

[Jamminman]

Originally Posted by Bill Verburg

Very nice car!

The heart of a track oriented brake setup is primarily the rotors and secondarily the supporting structure that keeps the rotor temps down

JJD's setup here has at it's heart 930 rotors, 32x304 front and 28x309 rear, the better the rotors the less support they need. Support is things like cooling, fluid, pads and weight loss

930 calipers on 930 rotors generate 1961/1242 n-M of torque @70bar line pressure
993 on 930 generate 1968/1162

to get get more torque bigger rotors are needed, 993RS 32x322 and 28x322 generate 2306/1618 N-M w/ 993RS calipers, again @70bar line pressure


go crazy and put 997GT3 gen 2 calipers on matching 34x380 and 28x350 rotors and you can generate 3263/2002 N--M



the problem w/ big brake torque is that you need sticky tries and lots of normal force to utilize it

For normal 911s w/ up to ~325 hp and less than ~3k # 930s are going to provide more than sufficient torque and thermal capacity especially w/ good supporting structure

If I'm interpreting correctly, there seems to be little difference in potential torque between the 993RS calipers and 930 calipers as the numbers on the same rotor (930 rotors you quoted above) are virtually identical. The potential benefit of the 993RS setup is the ability to take advantage of larger rotors. Of course, on a 2500lb car (or less) it might take slicks to appreciate the difference?

Corollary question: can you use larger rotors with the 930 calipers (or Elephant Racing for that matter)?