Thinking Brake Upgrade

[Bravoaloha]

I was thinking of starting a thread regarding a new brake kit I saw, but have yet to get around to it. This thread seems like it might be the proper place!

My car needs alot of sorting before I get to a brake upgrade but it is something I have always been interested in and read about. I intend to keep 15" wheels so my feeling (besides proper set-up of my Carrera brakes) was that someday I would invariably bite the bullet and go for 930 brakes.

I saw this kit and was wondering what people thought compared to a 930 set up. I believe it was just recently released so I doubt anyone has it yet.

Big Brake Kit — Stuttgart Classica

Thoughts?

[racer]

2900# wet SC.. + you and passenger? so.. 3300# SC?

anyway..

I would consider first an upgrade to the 3.2 Carrera (24mm rotors) first.
I would also consider better brake ducts than just the underarm mounts. you need to funnel air in from the valance somehow (replacement valance? cut out holes etc).


fwiw, my SC had 964/951 style calipers on slightly undersized rotors which, while making for some unusual pad wear, were nice. . the balance was nice and they lasted on long weekends at big tracks (3-days at Watkins Glen or Pocono) with no fade issues running Hawk Blues and ATE Gold.

My SC had the same under-arm ducts but cooling improved dramatically when installing a front mount oil cooler required a new front valance, one with holes for brake duct routing.


Of course, the obvious smart aleck response is simply "brake less, it just slows you down"

[VFR750]

No, 2900# including fuel (wet) and me only.

[VFR750]

After a lot of thought...

First Step:
1) Wide-A calipers
2) 84-89 Carrera 24mm rotors
3) Pagid RSH-29 Pads
4) Keep brake cooling scoop and plumbing
5) delete the hub blocker plate (better hub cooling)

$200 for the used calipers, $148 for new rotors.

After this, if I still see fade, sponginess, venting brake fluid, and weeping bearing caps at Thompson Motor Speedway, then I will upgrade more.

In mid-July, when it hits +95F humidity, and after the second run, I'll know if this was enough.

I still think the StopTech Level 1 Front is a good option. The upgrade directly adds significant rotor cooling with a 28mm wide floating rotor, with much more efficient spiral cooling vanes. Plus it is a drop in, with no other mods.

Since shedding rotor heat is the solution, both Rebel Racing and StopTech offer 28mm wide floating rotors in the front. Both should be able to dump a lot of heat, with the Rebel rotor at 318mm vs 282mm being better.

The conversion to the Boxster S/996 caliper adds a lot of extra work; 930 master cylinder and 14mm front wheel spacers. (new studs) but also gains 24mm rear rotors.

The front 996 caliper spaced for the 318 rotor fits, but just barely on a 16x6 ET36 Fuchs with the 14mm spacer, and similarly just fits a 16x7 ET23.3 Phone Dial without a spacer.

[786]

Originally Posted by Bravoaloha

I saw this kit and was wondering what people thought compared to a 930 set up. I believe it was just recently released so I doubt anyone has it yet.

Big Brake Kit — Stuttgart Classica

Thoughts?

2700 GBP seems expensive when they appear very similar to the C12 kit offered at early911 for 1100 GBP ($1400).

Speaking of which, has anyone on here tried the early911 kit and have an opinion? Strongly considering this for a decent upgrade that can fit under 15”s

Calipers

[Bill Verburg]

Originally Posted by VFR750

After a lot of thought...

First Step:
1) Wide-A calipers
2) 84-89 Carrera 24mm rotors
3) Pagid RSH-29 Pads
4) Keep brake cooling scoop and plumbing
5) delete the hub blocker plate (better hub cooling)

$200 for the used calipers, $148 for new rotors.

After this, if I still see fade, sponginess, venting brake fluid, and weeping bearing caps at Thompson Motor Speedway, then I will upgrade more.

In mid-July, when it hits +95F humidity, and after the second run, I'll know if this was enough.

I still think the StopTech Level 1 Front is a good option. The upgrade directly adds significant rotor cooling with a 28mm wide floating rotor, with much more efficient spiral cooling vanes. Plus it is a drop in, with no other mods.

Since shedding rotor heat is the solution, both Rebel Racing and StopTech offer 28mm wide floating rotors in the front. Both should be able to dump a lot of heat, with the Rebel rotor at 318mm vs 282mm being better.

The conversion to the Boxster S/996 caliper adds a lot of extra work; 930 master cylinder and 14mm front wheel spacers. (new studs) but also gains 24mm rear rotors.

The front 996 caliper spaced for the 318 rotor fits, but just barely on a 16x6 ET36 Fuchs with the 14mm spacer, and similarly just fits a 16x7 ET23.3 Phone Dial without a spacer.

I'd add brake fluid to the list, The best all around is Castrol SRF, there are others that have higher dry Bps but none w/ a better wet, The wet is the one to go by.

As for the other kits
the main issue is getting enough rear brake to balance the front and get the best utility from the system, the 996 aka Boxster s front is great, particularly so if the rotors have a floating annulus, the the Boxster S rears only give you a bias of 1.814, when you want more like 1.5 or possible a little less if the car is setup right. Better bis can be had if you use the Boxster S front w/ stock 3.2 Carrera rear, this is 1.544

Another option is to use 993 rear on the Carrera 3.2 rear rotors this gives 1.483, issue is I don't know how doable that is, I've used the 993 rear on 930 rear rotors but they are much larger than the 3.2 rears

[Bill Verburg]

Originally Posted by 786

2700 GBP seems expensive when they appear very similar to the C12 kit offered at early911 for 1100 GBP ($1400).

Speaking of which, has anyone on here tried the early911 kit and have an opinion? Strongly considering this for a decent upgrade that can fit under 15”s

Calipers

here's another example of a brake up grade that is purely cosmetic,

The only issue w/ stock 911 brakes when used on the track is heat management, or rather the lack of adequate heat management. The heavier or more powerful the car the more the issue arises.

Heat management is centered primarily on the rotors and secondarily on convective processes that cool the rotors. To that end better thermal performance is obtained form larger and better designed rotors, the design comes from the geometry of the internal structure. Larger rotor is straight forward, but what's not so obvious is the internal structure. 911 rotors thru '89 have an older less efficient straight vane design, modern rotors will have curved vanes, these are chiral, ie there is a left and right structure and when installed on the correct side flow more air.

The calipers you link to are certainly cool looking but they use the same old stock 911 rotors, only now due to larger caliper pistons they are trying to force more heat through the rotors which were already deficient in that regard.

[VFR750]

Yes, I should have listed the castrol SRF.

Bill,

That’s the dilemma with the upgrades. All seem to mess up the bias, or cause issues with adapters and worse, cutting tangs off the rear swing arm. I’m not going to do that.

So that’s what brings me back to the stop tech front upgrade.

The large 28mm wide floating rotor is the direct path to shedding the heat. Except the 930 rotors, all others are the same 28mm wide.

I checked the piston size for the ST42 caliper and it is only minimally larger, so the bias is close.

The downside is the rear. But again all upgrades are 24mm wide with varying levels of complexity in the path, with the Wide-M as the most direct, with a rear bias increase.

I also appreciate the dialogue because it forces me to think it through from multiple perspectives. May or may not agree. But smarter for the effort.

[3rd_gear_Ted]

Originally Posted by madcorgi

Mike,

First of all, kudos for running an air cooler on track! Great to hear you are using it as intendd.

I second what has been said by Ed about technique. I instructed for 20 years and raced before (and during) that time. When I first started, I used to cook brakes all the time. As I continued to get better, I used the brakes less, to the point where they ceased to be an issue. I think what happens is that as we become more accustomed to high velocities, our adrenalin calms down a little, so we get better at controlling our muscle movements. That makes us sooth. This guy has a few thoughts on the subject.

For the 14 years I ran my pretty gnarly 944S2/968 track car, I had best luck with Performance Friction 08 compound (they renumbered them--I'm not sure what the equivalent is now). They were rotor friendly, worked cold, yet lasted well and tended not to boil fluid as fast. But the best thing was their nice, linear and progressive feel. I used ATE Super Blue and later Motul 600, and I bled the brakes every track day, no exceptions.

I also have never liked the way big brakes affect steering and handling. All through the time I ran my 944, I resisted the urge to move up to M030 front brakes, which were an option. I drove a lot of M030 cars, and I thought they lacked the nimble feel of the lesser brakes. I try to avoid super big (and heavy) wheels and tires for the same reason. the beauty of the 911 is its lightness.

Absolutely correct, brakes are overrated, just do your air cooled 911 homework and you'll be fine.

[VFR750]

996 calipers are ~4 lbs lighter than Wide-A calipers. Each.

I curently own both. The “big brakes” are actually lighter because the calipers are made from aluminum which is 1/3rd the density.




The 2-pc rotors should also be lighter since the hats at aluminum top and the wider disk is wider because of more “air” between the flat disks. The 24mm rear hub is probably a little heavier that the 20mm. Again, mostly wider “air” and not the flat disk portions.

[786]

Originally Posted by Bill Verburg

here's another example of a brake up grade that is purely cosmetic,

The only issue w/ stock 911 brakes when used on the track is heat management, or rather the lack of adequate heat management. The heavier or more powerful the car the more the issue arises.

Heat management is centered primarily on the rotors and secondarily on convective processes that cool the rotors. To that end better thermal performance is obtained form larger and better designed rotors, the design comes from the geometry of the internal structure. Larger rotor is straight forward, but what's not so obvious is the internal structure. 911 rotors thru '89 have an older less efficient straight vane design, modern rotors will have curved vanes, these are chiral, ie there is a left and right structure and when installed on the correct side flow more air.

The calipers you link to are certainly cool looking but they use the same old stock 911 rotors, only now due to larger caliper pistons they are trying to force more heat through the rotors which were already deficient in that regard.

Seems not purely cosmetic?

"Now available, the very latest development in 911 brake upgrades, the Carbon 12 manufactured 6 pot front and 4 piston rear CNC machined aluminium calipers. Available for all 911s from 1969 to 1989 with 20 mm or 24 mm discs and “S” front struts (3.5” caliper spacing). It is a simple upgrade to fit 24 mm instead of 20 mm discs, and we always recommend fitting new discs with any caliper change. We can also supply an upgrade to front 300 x 30 mm custom discs and bells. These calipers can also be fitted to struts with 3” fixings if combined with the 300 x 30mm discs and bells.

Having fitted the calipers you can upgrade the discs at a later date, just purchase wider spacers to suit the thicker discs. An upgrade to the 300 mm discs will require a spacer for the caliper bracket as well, also available separately.

The front 6 pot caliper weighs 2795g complete, a Turbo caliper weighs 3420g so these offer a considerable weight saving, importantly unsprung weight, over the usual big brake upgrade for 15” rims."

[Bill Verburg]

Originally Posted by 786

Seems not purely cosmetic?

"Now available, the very latest development in 911 brake upgrades, the Carbon 12 manufactured 6 pot front and 4 piston rear CNC machined aluminium calipers. Available for all 911s from 1969 to 1989 with 20 mm or 24 mm discs and “S” front struts (3.5” caliper spacing). It is a simple upgrade to fit 24 mm instead of 20 mm discs, and we always recommend fitting new discs with any caliper change. We can also supply an upgrade to front 300 x 30 mm custom discs and bells. These calipers can also be fitted to struts with 3” fixings if combined with the 300 x 30mm discs and bells.

Having fitted the calipers you can upgrade the discs at a later date, just purchase wider spacers to suit the thicker discs. An upgrade to the 300 mm discs will require a spacer for the caliper bracket as well, also available separately.

The front 6 pot caliper weighs 2795g complete, a Turbo caliper weighs 3420g so these offer a considerable weight saving, importantly unsprung weight, over the usual big brake upgrade for 15” rims."

If you use 300x30 rotors then it's an upgrade, otherwise not, you'd want them in back too

The weight is not a significant factor here. yes, it's nice to lower unsprung weight but that isn't a primary concern.

W/ most of these sort of kits the f/r bias also goes out the window, no way of knowing w/ more details, but from what I've seen of Stoptech and Brembo kits, the consensus is to provide overkill in front and let the rear slide, this is the safe way to do things but doesn't utilize the the braking assets to the fullest extent.

If you want to use them great, I wouldn't

[786]

Is there a plug n play brake bias adjuster/proportioning valve available for our cars?

Like this: http://tiltonracing.com/product/standard-remote-brake-bias-adjuster/

Or id imagine universal would work too.

[Bill Verburg]

Originally Posted by 786

Is there a plug n play brake bias adjuster/proportioning valve available for our cars?

Like this: Standard Remote Brake Bias Adjuster - Tilton Engineering

Or id imagine universal would work too.

p/v are only useful when the rear is too much, they are not at all useful for when the front is too much

[VFR750]

Yup, 996 calipers with 318-28 front rotors from rebel racing is certainly overkill too. Front is biased over 1.72 and almost 1.9 when correcting for the added radius.

We will see come May. SCDA will be at Thompson and I will be too, with my Wide-A calipers.

[Bill Verburg]

You might think about losing some weight too, f/g f/r bumpers would be a real nice first step as the car will be lighter and the reduced polar moment will be very nice

the stock front bumper and valance is 30# w/ fogs, the rear is 24#, shock mounts are additional

[VFR750]

Bill

I’ve decided to not mess with the bumpers and such. I still drive it in the street and every little bit helps.

Not to justify, just to inform.

Thompson turn 1:
117+ mph to 45 mph

Less than 20 seconds later turn 4:
75+ mph to 35 mph

Brakes start to get a little toasty heading into turn 4. Zero useful runoff in pretty much the whole track.

For those who have not seen it here are some laps at Thompson Motor Speedway in Thompson, Connecticut


Technical track.

[VFR750]

Some more Info on the Level 1 Front Kit

Calipers

Rotors

Installation Clearance looks really nice for the smaller wheels.

[911tracker85]

p/v are only useful when the rear is too much, they are not at all useful for when the front is too much

I had installed just the boxster front brake upgrade on my 85 911, along with cooling ducts from the front bumper to plates on the hub. when flushing my fluid at the start of a DE year, decided to install a rear PV in the process, a tilton. after playing with it, ended up opening all the way. there is a stock PV that restricts the rears, and for stock/street that may be fine. but opening up the PV with the 'bigger' front calipers allowed me to get the most out of what I had. that, and learning how to properly brake. Motul and Pagid yellow pads.

when I retired it and built an 86 944 turbo, rebuilt all of the stock calipers and added 3" cooling ducts. so far have worked great, but do not go to tracks that really push the brakes, so we'll see if I get to one that does. I replaced the stock PV with an adjustable, but found the rears on the 944T were too much to open it up much.

glad I picked up a set of 930 calipers for my SC/930 conversion several years ago, got a good deal. just sent the rear calipers to be machined to bolt to the SC arm. finally into the uphill side of this restoration.

good luck on finding a good solution for YOU.

[Bill Verburg]

Originally Posted by 911tracker85

I had installed just the boxster front brake upgrade on my 85 911, along with cooling ducts from the front bumper to plates on the hub. when flushing my fluid at the start of a DE year, decided to install a rear PV in the process, a tilton. after playing with it, ended up opening all the way. there is a stock PV that restricts the rears, and for stock/street that may be fine. but opening up the PV with the 'bigger' front calipers allowed me to get the most out of what I had. that, and learning how to properly brake. Motul and Pagid yellow pads.

when I retired it and built an 86 944 turbo, rebuilt all of the stock calipers and added 3" cooling ducts. so far have worked great, but do not go to tracks that really push the brakes, so we'll see if I get to one that does. I replaced the stock PV with an adjustable, but found the rears on the 944T were too much to open it up much.

glad I picked up a set of 930 calipers for my SC/930 conversion several years ago, got a good deal. just sent the rear calipers to be machined to bolt to the SC arm. finally into the uphill side of this restoration.

good luck on finding a good solution for YOU.

Not sure that I understand the point here
for an '85 w/ Boxster front and stock rear the bias is 1.554, right about where you want to be w/o a p/v, if the stock p/v is retained you are losing out on the rear under most braking conditions, so yes if you installed an adjustable one then you would want to run it wide open.

944 has very different brake needs from a 911

930 is what Mike(VFR750) ought to be shooting for.

If you haven't already you will want a 23.8mm m/c