Simple Brake Upgrades for Track?

[David Inc.]

So a few weeks back I had the 911 at Grattan Raceway, which turned out to be much harder on my brakes than other tracks I've had the car on (Roebling, CMP, Barber, Waterford Hills). I haven't gone much into upgrades, only using Hawk HP+ pads with Motul 600 RBF (all other components either new or rebuilt), which has been sufficient for those other tracks but I started to notice fade and boiling fluid at Grattan.

Some pad fade I'm used to, that's consistent and predictable, but the fluid issue meant I had to pump the brakes on the front straight each lap and back way off on the brakes going into turn 1 to have enough in them for the rest of the lap. Not the end of the world, but it's a confidence killer when it happens.

Aside from going to a track only fluid with higher temp, any suggestions without getting into new calipers? Anyone have luck with brake ducting? It's still primarily a street car so I'd like to keep it "not too crazy".

Grattan is a great track. A real challenge to learn with all of the blind corners and elevation changes, but a treat when it starts to come together! Turn 3 can lick my butt, though, off-camber downhill corner with a braking zone over a crest? Yeah I'm not bothering with that nonsense in an old 911.

[Bill Verburg]

Originally Posted by David Inc.

So a few weeks back I had the 911 at Grattan Raceway, which turned out to be much harder on my brakes than other tracks I've had the car on (Roebling, CMP, Barber, Waterford Hills). I haven't gone much into upgrades, only using Hawk HP+ pads with Motul 600 RBF (all other components either new or rebuilt), which has been sufficient for those other tracks but I started to notice fade and boiling fluid at Grattan.

Some pad fade I'm used to, that's consistent and predictable, but the fluid issue meant I had to pump the brakes on the front straight each lap and back way off on the brakes going into turn 1 to have enough in them for the rest of the lap. Not the end of the world, but it's a confidence killer when it happens.

Aside from going to a track only fluid with higher temp, any suggestions without getting into new calipers? Anyone have luck with brake ducting? It's still primarily a street car so I'd like to keep it "not too crazy".

Grattan is a great track. A real challenge to learn with all of the blind corners and elevation changes, but a treat when it starts to come together! Turn 3 can lick my butt, though, off-camber downhill corner with a braking zone over a crest? Yeah I'm not bothering with that nonsense in an old 911.

Motul 600 is pretty good @400/617 wet/dry boiling points but not the best
Castrol SRF @518/608 has that title, it's head and shoulder s better than the second place Torque RT70o @ 439/683

the eat # is the one to use unless the fluid is changed for each days event

Besides that the usual items in no particular order are
lose weight
learn not to use the brakes
bigger front rotors
ducting
track oriented pads like PFC or Pagid Yellow

[stownsen914]

Better fluid, ducting, and brake pads (which you may have covered already) are good, lower cost ways to reduce brake fade on a that's car susceptible to it.

[Locker537]

Originally Posted by Bill Verburg

Motul 600 is pretty good @400/617 wet/dry boiling points but not the best
Castrol SRF @518/608 has that title, it's head and shoulder s better than the second place Torque RT70o @ 439/683

the eat # is the one to use unless the fluid is changed for each days event

Besides that the usual items in no particular order are

lose weight
learn not to use the brakes
bigger front rotors
ducting
track oriented pads like PFC or Pagid Yellow

Bill got it right.

On my SC, I've upgraded to 3.2 Carrera "Wide A" calipers to take advantage of a bigger rotor front and rear.

I run PFC pads.

ATE fluid.

I have backing plate ducting on the front brakes.

If I were you, I'd upgrade pads and fluids first. If you still experience fade, I'd do the Wide A + ducts together. Both SC and Wide A calipers use the same pads and they bolt right up.

[Bill Verburg]

24mmm front rotors provide an incremental improvement in thermal envelope over the 20mm rotors

but

I wouldn't use them in back as the usual 3.2 Carrera calipers needed move bias too far back, this causes the use of a p/v to be very desirable for big track use(but at the same time desirable for A/X)

[Jeff Higgins]

A lot of us run a cooling kit like this one. On your SC, you have the option of ducting it to the fog light openings (if you have them) or mounting the scoops to the a-arms.

https://www.pelicanparts.com/More_Info/PELPBSCBPAZK.htm?pn=PEL-PBSCBPAZK&bc=c&SVSVSI=0570

I think these are the fog light inserts you would need:

https://www.pelicanparts.com/More_Info/PELMOOOSCPKN.htm?pn=PEL-MOOOSCPKN&bc=c&SVSVSI=4240

Here are the scoops that mount to the a-arms:

https://www.pelicanparts.com/More_Info/PELMAOOSCOZN.htm?pn=PEL-MAOOSCOZN&bc=c&SVSVSI=4240

Here are the a-arm scoops mounted:



I think the fog light ducting is much preferred. You can see from the above just how vulnerable the a-arm scoops might be. Here is one of mine, after a fall drive:



I've since removed them and have now gone with Carrera Wide A calipers on the front. I know you don't want to do that for now, but this change proved to be more effective on the track for me than the ducting was.

[Locker537]

Originally Posted by Bill Verburg

24mmm front rotors provide an incremental improvement in thermal envelope over the 20mm rotors

but

I wouldn't use them in back as the usual 3.2 Carrera calipers needed move bias too far back, this causes the use of a p/v to be very desirable for big track use(but at the same time desirable for A/X)

Apologies, I wasn't clear and may have used the wrong terminology.

I have 3.2 Carrera calipers on both front and rear, mirroring what came with the 3.2. Fronts on the front, rear on the rears.

If I remember correctly, the SC came with a non-vented rotor on the rare, right? So the upgrade to 3.2 Carrera calipers allows for a vented rotor in the rear.

[David Inc.]

Thanks all for the input!

Originally Posted by Bill Verburg

Motul 600 is pretty good @400/617 wet/dry boiling points but not the best
Castrol SRF @518/608 has that title, it's head and shoulder s better than the second place Torque RT70o @ 439/683

the eat # is the one to use unless the fluid is changed for each days event

Besides that the usual items in no particular order are
lose weight
learn not to use the brakes
bigger front rotors
ducting
track oriented pads like PFC or Pagid Yellow

Thanks, I'll look into the SRF. I noticed many at the last track day were using it. Only bummer is I have about a hundred dollars worth of the Motul on my shelf!

As for the bolded, I know grass and trees slow the car but I'd prefer to keep the car on the track instead. I think I know what you mean, though, but I'm comfortable carrying more speed at corner entry than the traditional "slow in fast out" beginner's approach. If the car isn't sliding on its way to the apex then I'm usually doing something wrong.

Originally Posted by Locker537

Bill got it right.

On my SC, I've upgraded to 3.2 Carrera "Wide A" calipers to take advantage of a bigger rotor front and rear.

I run PFC pads.

ATE fluid.

I have backing plate ducting on the front brakes.

If I were you, I'd upgrade pads and fluids first. If you still experience fade, I'd do the Wide A + ducts together. Both SC and Wide A calipers use the same pads and they bolt right up.

Are the Wide A calipers the stock calipers from the 3.2?

Originally Posted by Jeff Higgins

A lot of us run a cooling kit like this one. On your SC, you have the option of ducting it to the fog light openings (if you have them) or mounting the scoops to the a-arms.

I've since removed them and have now gone with Carrera Wide A calipers on the front. I know you don't want to do that for now, but this change proved to be more effective on the track for me than the ducting was.

Thanks for the photos, very helpful! I can see you relocated your sway bar, would that routing have worked with the stock bar location? I can see how the fog light location would be better but I have the SC front valance with the external fogs--no dice.

[Jeff Higgins]

Yup, the Wide A caliper is simply the stock unit on the 3.2 Carrera. It honestly looks to me like no more than an SC caliber with a 4mm spacer fitted between the halves. I wonder if we could make one by doing that... You do need the thicker disc as well. It all bolts up with no other modification. These parts are very common and relatively cheap, since they are not some exotic turbo, RSR, or something similarly cool.

That is the early through the body sway bar setup, stock location on early cars. Your car has the holes in the tub for it, so it can be easily retrofitted. Some think it is superior to the newer SC and Carrera setup, but I think they are splitting hairs.

I wound up zip-tying the scoops to the a-arms so I could easily remove them for street driving. These poor things lead a very hard life on the street. If you decide to run them, either get a few spares or come up with some easy way to remove them when not on the track.

One more thought - do you still have the backing plates in place? Simply removing them really helps, and is free.

[ErrorMargin]

I think better pads are the cheapest and easiest way to go. I run ST43 pads and Motul 600 on my Dodge Caliber race car (not a Porsche) with stock calipers and rotors and I have more than enough braking power for my endurance races. I run treadwear 200 tires as well, Yokohama AD08R.

I've raced at Thunderhill, Buttonwillow and Sears Point and have never experienced any brake fade with this setup.

[David Inc.]

Originally Posted by Jeff Higgins

Yup, the Wide A caliper is simply the stock unit on the 3.2 Carrera. It honestly looks to me like no more than an SC caliber with a 4mm spacer fitted between the halves. I wonder if we could make one by doing that... You do need the thicker disc as well. It all bolts up with no other modification. These parts are very common and relatively cheap, since they are not some exotic turbo, RSR, or something similarly cool.

That is the early through the body sway bar setup, stock location on early cars. Your car has the holes in the tub for it, so it can be easily retrofitted. Some think it is superior to the newer SC and Carrera setup, but I think they are splitting hairs.

I wound up zip-tying the scoops to the a-arms so I could easily remove them for street driving. These poor things lead a very hard life on the street. If you decide to run them, either get a few spares or come up with some easy way to remove them when not on the track.

One more thought - do you still have the backing plates in place? Simply removing them really helps, and is free.

Good information, thanks. And I do still have the backing plates mounted--any downsides from removing them aside from a healthy coating of brake dust in the wheel well?

[Jeff Higgins]

I think the backing plates are there more as an attempt to keep small rocks and other debris out of the brakes, rather than any dust control. I don't think you will see any more brake dust in the wheel wells, at least I saw no noticeable difference. With or without the backing plates, most of it seems to wind up inside the wheel itself anyway. I didn't notice any increase there either.

[David Inc.]

Worth a shot, my experience with backing plates has typically been them capturing gravel and grinding them into the rotors.

[Bill Verburg]

For track use backing plates are more nuisance than help

for ducts to be at all effective they need to be large, 4" is too small, and straight

Here's a minimal solution



if using 3", use multiple stacked ducts


the intake for ducts need a large entry plenum w/ rounded/tapered transition to the ducts

the intake wants to be as close to the centerline of the car as possible and vertically oriented is better than horizontal

a much more efficient way to get air to the rotors is scoops fastened to the A-arm

cooling scoop on left, the one on right is to protect electrical components

[David Inc.]

Any thoughts on the use of 993 deflectors?

[trentwat]

Originally Posted by Bill Verburg

For track use backing plates are more nuisance than help

for ducts to be at all effective they need to be large, 4" is too small, and straight

Here's a minimal solution

I’m no expert, but what Bill shows from a cooling perspective does seem to help on spirited mountain drives…I have been often told that the 3.2 brakes with proper cooling, pads (Pagid street/track) and ATE fluid was a solid set up.

My ducts run from where fog lights might be…albeit mine are glassed in ducts on a Getty FRP bumper…I was having trouble with the NERP setup, because the hose kept rubbing on the tires until they pulled off. I was able to purchase a set of the clamshells from Smart Racing products (remnant stock) which clamps over the suspension...similar to Bill’s set up.

https://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/888619-fs-smart-racing-products-front-brake-cooling-kit.html

At some point, I might consider the Elephant Racing upgrades…supposed to be a Turbo brake style design which are a direct fit for non-turbo cars. I’d be curious what others think of this product…mixed reviews on Boxter brakes, and old-stock Turbo brakes aren’t really out there as far as I can tell.

[PeteKz]

David, short of going to larger rotors, one other thing you can try that will give a little more margin before the fluid boils: Use new pads at Grattan. New pads are thicker than used pads, so will provide more "insulation" between the hot rotors and the calipers. Since you don't have this problem at other tracks, that might be just enough to prevent boiling at Grattan. One other trick Ive heard about is to insert titanium or stainless steel shims between the pads and caliper pistons. It supposedly reduces the heat transfer to the pistons.

[Jeff Higgins]

Originally Posted by Bill Verburg

For track use backing plates are more nuisance than help

for ducts to be at all effective they need to be large, 4" is too small, and straight

Here's a minimal solution

I like how you got past the a-arm with the solid piece of PVC. Nice, elegant solution. David, however, says he has no option for a forward mounted intake for the ducting. I think he might be kind of stuck with the a-arm mounted scoop if he elects to do this.

Originally Posted by Bill Verburg

a much more efficient way to get air to the rotors is scoops fastened to the A-arm

cooling scoop on left, the one on right is to protect electrical components

I must admit to a bit of confusion here. Please excuse my ignorance as an old long hood driver, but I see lots of unfamiliar components in this photo. This must be your 993, no? Is that the oft mentioned 993 brake duct? Will it fit David's SC?

In the end, after having gone round and round with ducting and other solutions, my "final fix" was to install Wide A calipers and discs. I started with the aluminum "S" calipers, went to iron SC calipers (so I could retain the same discs), tried several variations on ducting (including my "911R" horn grille treatment shown below), and finally tried the Wide A solution (at Bill's suggestion). That simple fix fixed everything. While the 911R treatment remains, I have no other ducting. Even on slicks, I simply cannot "use up" my brakes at a track day anymore.



Just for old time's sake, the right side. The holes date from problems I had with oil cooling, not brake cooling. I installed a second cooler, ST style, and solved that problem, but I kept the bumper holes that have been there for 20 years. Kind of a "signature" item on my car.

[DWeg1998]

I had good luck at the track switching from ATE to Motul 600 and removing the rock guards

[Cory M]

The Motul 600 is decent fluid. Those hawk HP+ pads don't sound like they're up to the task of real track duty. Someone mentioned the Raybestos ST43s, they are great pads and gentle on rotors. Unfortunately when I tried to order them in February they were back ordered with no ETA. I ended up going with Performance Friction pads, they are good and similarly priced. You should call Porterfield Enterprises. They sell most popular brands and have come through with great recommendations for me several times.

The readily available 2.5 in 911 brake duct kits that feed the center of the rotor are very effective. I don't like the little scoops that hang under the control arm, they are lost pretty easily if you go off track, much better if you can run it to an opening in the valance.