Porsche Brembo 996 BBK Conversion-- let's figure out how to fix the dust boots/seals

[Obioban]

In terms of rebuilding the calipers frequently...

If Girodisc pressure seals hold up (I'll remove some dust boots to see if I find shavings like with stoptech ones pictured above), then they should be good and I'll be a happy camper. Because replacing the pressure seals gets messy with all the fluid.

If I keep playing musical chairs with dust boots between Girodisc, FCP Brembo, etc, that's not that terrible as they can be swapped with caliper and fluid line connected to the car (in worst cases at least the fluid line and pistons don't need to be removed and nothing gets messy with fluid everywhere).

If someone is trying the magical blue dust boots, report back, assuming that's the only variable you change.

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My friend with the brake failure in the video is going to try just the blue boots, and is going to try them as the only change at his next event.

I really want that to be enough of a solution, as I don't want to be fiddling with heat shields for the rest of time...

[nyc951]

Obioban

you may have mentioned it already, but why did you change your Brembo kit out for the 996 calipers?

The Rennlist forums have a lot of good information that might be helpful.

[Obioban]

Obioban

you may have mentioned it already, but why did you change your Brembo kit out for the 996 calipers?

The Rennlist forums have a lot of good information that might be helpful.

FCP sells 996 track pads and CSL/ZCP rotors. That eliminates... 1/4-1/3 the cost of tracking

In every other way, the Brembo kit is hugely better. Lighter, pads last longer, rotors last longer, better pedal feel, no dust boot issues.

... I'm not entirely sure I made the correct choice.

[Casa de Mesa]

Yeah but good on you for trying to minimize the expense and find a more cost effective alternative. Eliminating brakes as a consumable is huge.

Really interested to hear how the blue boots work out for your buddy.

[Obioban]

Your difference in experiences with the factory rotor vs your Brembo BBK is interesting. I'm assuming you had a 355x32 kit, and while I don't have the weights of a Brembo ring, the GiroDisc 355x32 ring weighs in at around 17 lbs. The GiroDisc E46 M3 ring (ring only) weighs in at around 16 lbs, so the thermal mass is very similar. This passes my sniff test, because while the D1-012 factory-sized ring is 345x28, it has at least 10mm more annulus which makes it up. I don't have a recorded weight for the factory ring only, because we would have to cut the co-cast "hat" out...

Both the Brembo 355x32 ring and the GiroDisc 355x32 ring (and the E46 M3 ring) are 48-vane count. The factory rotor has 30 vanes, if my notes are correct. So the Brembo rotor would have more than 50% higher vane count, which lends itself to much more effective cooling. Brembo has also sold a 72-vane 355x32 (I think they call it Type 5) but I would suspect the ring in your kit was 48-vane.

tl;dr: it makes sense that your Brembo BBK was much more effective at cooling than the factory rotors, which matches your real-life experience. The factory rotors suck at cooling, relatively speaking.

Dust boots get toasted with track use, even the boots in my 997.2 GT3 with the 380mm setup (more than enough rotor for the car) are beyond disintegrated. Titanium pad shields will help, but at the end of the day the most robust boots are the EPDM units. The "high-temp" stuff is silicone if I remember correctly and tend to be fragile as heck.

I see ECS sells Girodisc rotors, and they qualify for their newly announced lifetime warranty program:
https://www.ecstuning.com/b-girodisc...ir-a2-152~grd/

Seems like this may be the actual solution! Real rotors that can get rid of heat, with a lifetime warranty!

... now hurry up and get those ZCP sized rotors on the market, please

[Obioban]

No new information here, but Brembo got back to me-- so thought I'd post further confirmation of what we've already established:

Based on your feedback as well as your experience with a GT upgrade system, it sounds like your driving level has graduated from the OEM Porsche calipers.

As far as dust boots, there is a good chance your OE calipers already have the same dust boots that are found on our GT calipers. The difference would be the internal pressure seal, but the GT seals would not be compatible with the OE calipers. If you're burning through dust boots its likely that you're exceeding the thermal capacity of the caliper itself. Dust boots & seals aside, the design of the GT caliper is going to have a higher thermal capacity and better heat resistance overall. Since GT is designed as an upgrade to the OE system, we take into consideration how hard the car can and will be driven, along with any potential increases over factory horsepower, aero, tires, etc.

We have had customers burn through boots on GT calipers, while this is primarily due to age, when we know it's a newer system we usually find out the driver is simply out performing the GT calipers, and then we get them into GT-S, or race systems if the car is no longer being street driven. You can checkout all the options we have for an E46 M3 here; http://www.racetechnologies.com/prod...0?vehicle=7760

Something else to consider is fluid, but if you're running the same fluid as you do with the GT setup, we can likely rule this out.

So, no dust boot upgrade options from Brembo.

[r4dr]

I see ECS sells Girodisc rotors, and they qualify for their newly announced lifetime warranty program:
https://www.ecstuning.com/b-girodisc...ir-a2-152~grd/

Seems like this may be the actual solution! Real rotors that can get rid of heat, with a lifetime warranty!

... now hurry up and get those ZCP sized rotors on the market, please

LOL, I'm curious how long that lasts. I know the supplier they would buy through, and if ECS wants to eat those replacement costs... I wish them luck.

The ZCP-sized fronts are on the market, the rears are all the same, aren't they? I doubt the rears would be a regular production item, just made in batches of 5 pairs at a time... but the replacement rings would be stocked.

[Cronenberged]

No new information here, but Brembo got back to me-- so thought I'd post further confirmation of what we've already established:



So, no dust boot upgrade options from Brembo.

When you re-upgrade to the GT calipers I would be happy to buy your 996's 😁

[nyc951]

FCP sells 996 track pads and CSL/ZCP rotors. That eliminates... 1/4-1/3 the cost of tracking

In every other way, the Brembo kit is hugely better. Lighter, pads last longer, rotors last longer, better pedal feel, no dust boot issues.

... I'm not entirely sure I made the correct choice.

Does anyone know if there is any noticeable improvement in brake pedal feel for a Competition car with the 996 brake caliper mod?

[Obioban]

Does anyone know if there is any noticeable improvement in brake pedal feel for a Competition car with the 996 brake caliper mod?

The 996 calipers feel better than stock for sure. Just not as nice as the Brembos.

[mrgizmo04]

Does anyone know if there is any noticeable improvement in brake pedal feel for a Competition car with the 996 brake caliper mod?

What does improvement in brake pedal feel mean to you? You want less pedal travel (that's what most associate), more initial bite, faster abs engagement, better at limit modulation? Everyone is after a personalized definition of that and it's subjective per your car use case.

Because of decrease in piston area vs stock, pedal travel decreases for same amount of force on the pad. I can tell you running super grabby pads like dtc70 the pedal feel to me is horrible at limit, modulation becomes non existent and pads work like an on/off switch. Brake release being most important and toughest thing to master to properly position the car at the limit, that feel sucks.

I know most audience for these is not track oriented, but painting the fuller picture. There are definitely compromises you need to learn to live with, with this kit.

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[nyc951]

What does improvement in brake pedal feel mean to you? You want less pedal travel (that's what most associate), more initial bite, faster abs engagement, better at limit modulation? Everyone is after a personalized definition of that and it's subjective per your car use case.

Because of decrease in piston area vs stock, pedal travel decreases for same amount of force on the pad. I can tell you running super grabby pads like dtc70 the pedal feel to me is horrible at limit, modulation becomes non existent and pads work like an on/off switch. Brake release being most important and toughest thing to master to properly position the car at the limit, that feel sucks.

I know most audience for these is not track oriented, but painting the fuller picture. There are definitely compromises you need to learn to live with, with this kit.

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Appreciate the thoughtful response. Good pedal feel to me would be firm and easily modulated braking. I don’t plan on tracking this car (much), but I’ll keep your feedback in mind.

[Epsilon]

What does improvement in brake pedal feel mean to you? You want less pedal travel (that's what most associate), more initial bite, faster abs engagement, better at limit modulation? Everyone is after a personalized definition of that and it's subjective per your car use case.

Because of decrease in piston area vs stock, pedal travel decreases for same amount of force on the pad. I can tell you running super grabby pads like dtc70 the pedal feel to me is horrible at limit, modulation becomes non existent and pads work like an on/off switch. Brake release being most important and toughest thing to master to properly position the car at the limit, that feel sucks.

I know most audience for these is not track oriented, but painting the fuller picture. There are definitely compromises you need to learn to live with, with this kit.

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Dumb question here: If you are on OE (Textar) pads, would you actually need more pedal travel to get the same braking power? Asking because I am assuming a decrease in piston area means more pedal travel needed and therefore more modulation. Thanks!

[mrgizmo04]

Dumb question here: If you are on OE (Textar) pads, would you actually need more pedal travel to get the same braking power? Asking because I am assuming a decrease in piston area means more pedal travel needed and therefore more modulation. Thanks!

You have the ratio backwards. For same master cylinder, smaller caliper pistons will result in less pedal travel, but would require more leg force. Don't skip leg day! If you want to skip leg day, you can get a higher mu pad. At the wheel, for same master cylinder and leg force what provides more braking torque are any of the 3 - larger diameter rotor, larger diameter pistons, higher friction pad.

For illustration, similar to getting a cyringe (master cylinder) to fill up a bath tub (large piston, it will take all the fluid in the syringe + then some), vs if we decrease the area of the piston and now need to fill up a thimble from same syringe (in this case the plunger will barely move). You are moving fluid from one reservoir to another, if destination is smaller than origin, you need fewer pump/less travel. This is reverse of a hydrolic jack where you need to raise a car by pumping the small piston 10 times.

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[SpaceJockey]

FCP sells 996 track pads and CSL/ZCP rotors. That eliminates... 1/4-1/3 the cost of tracking

In every other way, the Brembo kit is hugely better. Lighter, pads last longer, rotors last longer, better pedal feel, no dust boot issues.

... I'm not entirely sure I made the correct choice.

Which track pads are you running? It looks like they only offer DS2500 for the rears.