Question on 996 Brake Cooling and Servicing

[polizei]

Hey Guys,

I will be upgrading my '87 Carrera brakes to 996 NA in the coming weeks, and I'd like to install a front rotor cooling kit at the same time. Will the Rotor Cooling Kit sold here on Pelican for '76-89 911s work for 996 NA brakes?

Pelican Parts.com - Brake Rotor Cooling Kit

The scoops and ducting from this kit look like they'll work, but how about the brake backing plate? '76-89 911s have a front rotor diameter of 282 mm, and 996 Carreras have a front rotor diameter of 318 mm (Welcome to Rennsport Systems, Porsche Performance Products for the 21st Century). Is there a kit out there with a larger backing plate that's intended for late model setups? Also, I'm kind of surprised by the price on these, given how simple they look.

I'd like to get an idea of maintenance on these brakes. How frequently should the seals be replaced? Do you know where the seals can be purchased? Can't seem to find them here on Pelican. Is there anything else that should be replaced/greased when rebuilding these calipers? Is there a how-to guide for rebuilding the calipers?

Thanks guys,

[shahram]

I doubt you can get the rotorsand 996 break calipers on a 87 911 that hot so that it would need a break cooling kit. Save the money and go maybe with better break pads if needed at all. Just my 2 cent.

[tonythetarga]

I agree. You will probably be fine with the 993 style air deflectors that you can zip tie to the a-arms if you find you need cooling.

[KTL]

That cooling kit will work. Yes the backing plate is a bit smaller, but it'll still work well. I have Wilwood 309mm rotors on my racecar and I use the smaller backing plates typical to the original brakes. I have seen good results with my setup.

If you really want the backing plates to be bigger, there is a fellow on here who was making custom carbon fiber backing plates for people at a really good price. Carbon Fiber Brake Ducts finished

Seals on these calipers are more durable than the seals on the original iron Ate calipers. I think the Brembo alloy calipers shed heat a bit better and of course the bigger rotors are a larger heat sink and should also shed heat better. So the side benefit of the larger brakes is they reduce wear on your pads and rotors, plus the seals don't get cooked. You can get the seals and dust boots here on Pelican

Porsche 996 Brake Hydraulics - Page 3

or also from Zeckhausen Racing

Replacement Rotors, Pads, Hardware

Aside from replacing the seals, there's not much else needed to rebuild the calipers. A good idea to clean the pad guide plates inside the pad box area. These guide plates can get a lot of debris build-up on them and not allow the pad to move smoothly

While the bigger brakes need less cooling, its still a wise move to have cooling ducts to the brakes. The big brakes will run a bit cooler, but they still get extremely hot during track day use. With drilled/perforated rotors like the 996 rotors, they're more prone to cracking than full-faced rotors. So any cooling you can get to them is going to make them last longer. In the long run, brake cooling can save you a good bit of money on consumables like pads, rotors and caliper rebuilding.

[polizei]

Originally Posted by shahram

I doubt you can get the rotorsand 996 break calipers on a 87 911 that hot so that it would need a break cooling kit. Save the money and go maybe with better break pads if needed at all. Just my 2 cent.

Thanks for the reply. I definitely don't want to throw money at a problem that doesn't exist. Here's where I'm coming from:

1. I'm performing a turbo conversion on my '87 Carrera. Target is 450-475 HP. I'm running 225/17s up front and 255/17s in the rear.
2. 996 Carrera brakes run much hotter when tracked than the larger TT brakes. Yes, better pads and fluid will help with this.
3. This seems like relatively simple upgrade to perform "while you're in there". Ultimately $300 seems like cheap insurance to avoid brake fade on track days.

Perhaps it's smarter to wait until I track the car to see if there is any fade. Regardless and out of curiosity, are there rotor cooling kits more specific to the 996 rotors?

[shahram]

Aha, ok, well i would track the car and see if a cooling kit Is needed. If yes you still can add one and if not you save the hassle, money and the additional weight. Btw, I am pretty sure I have a 993 cooling kit laying somewhere in my warehouse

[KTL]

With the kind of straight line speed you can generate with almost 500 HP, you'd be foolish not to throw some kind of cooling means at the brakes. Better pads and fluid are just a band-aid to mask the excessive heat problem. The most effective way to rid the rotors of heat is cooling ducting. Yes, better pads and fluid can withstand more heat. But pads and fluid do little to protect the seals, rotors from heat abuse.

[polizei]

Originally Posted by KTL

If you really want the backing plates to be bigger, there is a fellow on here who was making custom carbon fiber backing plates for people at a really good price. Carbon Fiber Brake Ducts finished

Thank you for all the great info! I just sent a PM to Don to see if he can make any ducts specific to my setup. On that thread, I see that a lot of guys are channeling air to the ducts through holes in the front bumper rather than scoops. I'd prefer scoops so I wouldn't have to modify the front bumper. Do you know where I could pick up the scoops?

[KTL]

There's typically three ways that people have used to get air to the brakes on a 911

1. Thru-bumper ducting, which typically requires the conversion to a fiberglass bumper cap or modifying the stock valance (Carreras with their integrated fog lights make this easier than the SC).

2. A-arm mounted factory scoops. These are from the 964 and 993 cars and are factory pieces. The 993 ones are the best to go with and are cheap. For some reason the 964 parts are much more expensive, despite them being basically the same molded plastic piece.

Porsche 911 Suspension - Page 3

No ducting is connected to the scoops. They simply grab the air that is flowing under the car and deflect it toward the rotor face. I did this on my '87 a while back and it seemed to be helpful. I also installed them temporarily on my '79 racecar last year as an interim solution until I finally got around to plumbing the ducts from the bumper to the rotors.

Here's some good topics I chimed in on

993 brake deflectors

More brake cooling. . . 993 air deflectors option?

993 brake air deflectors on my 911, not!



3. A-arm funnels like the NERP or AJ-USA kit. These funnels are a tried and true way of ducting air to the eye of the rotor without the need for ducting plumbed to the front bumper.

[polizei]

Kevin - You're a wealth of information! It sounds like options 2 or 3 would suit me best. Is there any trouble fitting the 993 deflectors to a 911? Deflectors are a great deal cheaper than the funnels. Is there much of a difference in effectiveness?

And should I be installing the air deflector plates (http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_BRKprf_pg8.htm#item7) in addition to either of these solutions?

Thanks again!

[Vincent Hill]

I would also look into Seine Brake pad backing. They are made out of Ti which does not transfer as much heat to the Cylinders in the Calipers. This will help keep the Pedal harder longer. For less than $100 it sure will not hurt to have this.

Seine Systems > Ti Brake Shield

[spuggy]

Originally Posted by polizei

Thanks for the reply. I definitely don't want to throw money at a problem that doesn't exist. Here's where I'm coming from:

1. I'm performing a turbo conversion on my '87 Carrera. Target is 450-475 HP. I'm running 225/17s up front and 255/17s in the rear.
2. 996 Carrera brakes run much hotter when tracked than the larger TT brakes. Yes, better pads and fluid will help with this.
3. This seems like relatively simple upgrade to perform "while you're in there". Ultimately $300 seems like cheap insurance to avoid brake fade on track days.

Perhaps it's smarter to wait until I track the car to see if there is any fade. Regardless and out of curiosity, are there rotor cooling kits more specific to the 996 rotors?

I'd say run good pads and fluid, keep an eye on things and see how you go. You may find that you don't need anything more. I really don't think I do.

The 930 in my '77 currently makes ~425 FWHP. My car is probably somewhat lighter than yours, (middies had less tub bracing than SC's I'm told), but it's in the same ballpark otherwise (heh, ~6-7 lbs per HP is so much fun - you'll love it!). I'm also running 225/45/17 front, 255/40/17 rears (Z1 Star Spec).

I converted the brakes (previously 3.2 front/rear) to 996 NA. 996 NA rotors are like manhole covers in comparison to 3.2 rotors - good capacity upgrade.

If you just figure thermal capacity crudely as the volume produced by the diameter/thickness of rotor, 996 NA fronts are ~96% of the volume of 930 front rotors - which only the truly hardcore or very highly skilled seem to find inadequate or problematic for track use.

For comparison, by the same metric, 3.2 fronts are 65% of the volume of 930 front rotors. I'd take a SWAG and say that I think that the mounting bell on the stock 996 rotor style may add thermal capacity (and also weight, obviously) as compared to the bolt-up hat mounting.

One big reason for selecting 996 NA over 996TT was bias - I used Pagid Yellows on the fronts, and RS14 Blacks on the rear for "better" (closer to 1.6:1 front/rear) bias. Stopping is balanced, powerful and very progressive with very good feel/feedback - modulation either side of lockup is easy and intuitive. Scrubbing off speed from well into triple digits takes amazingly little road.

Everyone else who's driven the car since the conversion has really liked them (wrench came back with a wide grin saying "well, you won't be able to keep anything under the seats any more") - both instructors were very happy with pedal feel/modulation and overall brake performance.

Suspension also has an effect - both an asymmetric LSD and stiff suspension will change/influence how the car reacts to different amounts of front/rear bias. Apparently. I'm no expert.

I run a 40/65 LSD set to maximum (~75 ft/lb) lockup, and 21/30 TB's with stock middie sways. I had thought there was excessive body roll on hard cornering and was considering late 3.2 sways - but one of my instructors (who runs an SC race car amongst other things) says he really likes the way it handles and wouldn't change a thing.

I just ran at the track for two separate days recently, and I still think the brakes are very spiffy indeed. Really liked them on the street, they are way down on the list of my concerns on the track...

As far as rebuilding is concerned, I think you just buy pistons and dust seals - calipers themselves are relatively cheap new (even cheaper used), pads and rotors are off-the-shelf and widely available. As this car is also a daily driver, another attraction of this particular conversion was how readily available and price competitive replacement parts were - I got a new set of 4 German-made Bolo 996 rotors drop-shipped for $200; they were wrapped in "Sachs" greaseproof paper inside the factory box...

[polizei]

This forum is overwhelming! Thanks for the great information Spuggy, and I'm glad to hear such a success story with the 996 brakes on a 911! I researched which direction to go, and ended up taking Bill V's recommendation on the 996 NA brakes.

It sounds like the most bang-for-the-buck cooling solution is to use a combination of the hub block-off plates and the 993 air deflectors. I'm sold!

[spuggy]

Originally Posted by polizei

This forum is overwhelming! Thanks for the great information Spuggy, and I'm glad to hear such a success story with the 996 brakes on a 911! I researched which direction to go, and ended up taking Bill V's recommendation on the 996 NA brakes.

Brakes were on my "To-Do" list when I bought the car with a stock-ish 930 in it - the 3.2 brakes never felt confidence-inspiring... When I picked up the extra power, they just moved up the list - but I always felt 996TT was overkill for a lighter car, and the bias aspect bothered me as well. First discussed 996NA brakes with Dr. Timmins in 2007, but everything finally lined up last year

One thing - try as hard as you may, you'll not be able to get good pads like the Pagids to gas off on the street - just like the manufacturer says... I drove 1000's of miles on them, they felt bedded in and responded well (including at least one use in anger that would have saved the front of my car from a Corrolla that looked like he wasn't going to check mirrors before changing lanes)...

At the first track day they'll gas off properly, and you'll know this, because forever more they'll "sing" on all 4 corners when you apply them lightly, like in traffic. They shut right up when you're using them for real...

It sounds like the most bang-for-the-buck cooling solution is to use a combination of the hub block-off plates and the 993 air deflectors. I'm sold!

Yeh, that's some great info above, especially from Kevin. I may look into that if I start driving the car harder.

Right now, the car the brakes were originally designed for is something like 400 lbs heavier than mine, and the tires (well, operator fear is a factor, too!) limit the heat I can get into the brakes.

Without going ultra-sticky compound or wide-body, pretty sure that will remain true.

[Jaskas]

The 996na brakes are great! Im running stock pads wo any special cooling without any problems. The feel on track is unbelieveble and so is the stopping power. You can count on the brakes without worrying of fade.

Is have also 930 master cylinder and the propotion valve disassembled.

[Peter Bull]

I'm running 996 Carrera brakes with brake cooling. I made some funnels to replace the fog lights in the front valance, but otherwise the setup is the same as the PP one you refer to. I don't have the amount of horsepower you do, but it still works like a charm. No cooling problems

/Peter

[polizei]

Originally Posted by Peter Bull

I'm running 996 Carrera brakes with brake cooling. I made some funnels to replace the fog lights in the front valance, but otherwise the setup is the same as the PP one you refer to. I don't have the amount of horsepower you do, but it still works like a charm. No cooling problems

/Peter

Peter, Great write-ups! Thank you!

Where did you source the plates that fit on the inside of the brake rotors to channel the air?

[Peter Bull]

Originally Posted by polizei

Peter, Great write-ups! Thank you!
Where did you source the plates that fit on the inside of the brake rotors to channel the air?

Thanks, I got them at Smart Racing Products. They sell them separately.

/Peter