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

[audipwr1]

Demon Speed sells uprated boots
On these calipers in hard use environment expect 25-50hrs out of the dust shields max, its the rebuild cycle on my racecar with effectively this brake
The ceramic pucks help but fall out all the time and are a pain

[heinzboehmer]

glad I read this thread, before I invest more money into thi skit which ran perfectly fine at Sebring in HOT florida weatherr. I am scared to cehck the boots. I might just use this as an excuse to buy an AP KIT

Well, no dust boots on the AP calipers, so you definitely wouldn't need to worry about them then

[Tonggi]

glad I read this thread, before I invest more money into thi skit which ran perfectly fine at Sebring in HOT florida weatherr. I am scared to cehck the boots. I might just use this as an excuse to buy an AP KIT

[heinzboehmer]

Just another data point. Girodisc dust boots did not survive either

Swapped to a brand new set of Girodisc dust boots and installed the Bry5on scoops. Boots still look fine after a track day!

Same pads, same fluid, same track, same basically everything. Only real difference was the addition of the scoops. More analysis here: https://nam3forum.com/forums/forum/m...142#post279142

[D-O]

What street pads were you running?

Sent from my SM-S911U1 using Tapatalk

Hawk ceramic. I am not crazy about them. At the time the car was my daily, and I bought them in the hope that they would be clean. They have not let me down on that.

[mrgizmo04]

[QUOTE=D-O;n276867

This is the fist time I have noticed that the pads are a bit too tall and extend just a bit above the top edge of the rotors. They do fit nicely at the bottom. Is this to be expected?[/QUOTE]

Yes, once you get seriously moving and put enough heat in, the rings will expand radially and grind that off.

That said, at slower pace, you don't need to do anything with that edge, it will crumble away naturally, so you don't need to take anything out to clean.

Sent from my SM-S911U1 using Tapatalk

[mrgizmo04]

First ever track day. It seems I was not terribly hard on the brakes as my plain-Jane Centric dust boots held up.




This is the fist time I have noticed that the pads are a bit too tall and extend just a bit above the top edge of the rotors. They do fit nicely at the bottom. Is this to be expected?

What street pads were you running?

Sent from my SM-S911U1 using Tapatalk

[OPS]

Centric made the parts for stoptech and in 95% of the applications I recommended them. You have tons of pad which in itself is a nice thermal barrier. I would take out the pads, clean them up, and put them back in. But overall I wouldn't loose any sleep over that!

Mike

[D-O]

First ever track day. It seems I was not terribly hard on the brakes as my plain-Jane Centric dust boots held up.




This is the fist time I have noticed that the pads are a bit too tall and extend just a bit above the top edge of the rotors. They do fit nicely at the bottom. Is this to be expected?

[OPS]

TBH if lots of GT3 owners are tracking their cars with cracked boots, I’ll likely do the same until a definitive solution is found. Replacing the boots after every DE doesn’t sound fun lol.

I wouldn't run any dust boots if I was tracking that much tbh - its a waste of money and since your inspecting/cleaning the brakes after each event, no reason to!

I ran the dust boots on my E46 with 18z and 996 C4S and E90 M3 Rotors with no issues however I was on Michelins so heat wasn't as much an issue.

What I really wanted was an AP BBK....

Mike

[mrgizmo04]

would be nice if it was possible to run 345x32 rotors with the Porsche calipers.

I don't think it is. Pcar fronts are made for x28 stock Pcar discs (rears are made for x24, while we run them on x20, so don't let rear pads get too low ). While you can shave those pins/pad stoppers to fit a wider disc, you'd prob get rubbing as the middle part of the caliper is not wide enough. You are talking about tacking on 2mm on each end. I got so much radial expansion from the rotors that I got rubbing of the outer edge of the rotor on the caliper edges. Then also, to fit a wider rotor, since you are not widening the caliper, you'd need to shave 2mm off each pad (more if you want to run ti or other shims). Then you are losing heat capacity out of the box on the pad. I posted somewhere the size of the front Pcar pad is barely larger than stock M3 pad, so pads don't need any help getting overheated to start with.


Sent from my SM-S911U1 using Tapatalk

[SQ13]

Good point on the rotor width - would be nice if it was possible to run 345x32 rotors with the Porsche calipers. I’ve been thinking about making the switch to Girodisc. I’m not tracking the car enough these days to justify buying from FCP at MAP and using their exchange program, so I’ll prob just wait for the next Girodisc sale and buy elsewhere.

TBH if lots of GT3 owners are tracking their cars with cracked boots, I’ll likely do the same until a definitive solution is found. Replacing the boots after every DE doesn’t sound fun lol.

[Pklauser]

Sidenote for all, FCP now carries Girodisc rotors.

👀👀👀

Here's the link to the E46 ones: https://www.fcpeuro.com/products/bmw...irodisc-a1-012

Slightly awkward that you'd be exchanging the whole disc when you could theoretically just swap the rings.

[mrgizmo04]

It's weird that Girodisc boots are a popular solution for cracking OE boots in the Porsche GT world, but they don't work in our application. Are the 345mm rotors too small?

In total heat capacity sense they are small, being only 345mm (which is not bad), but they are also only x28 thick, most bbk applications run x32 at least. It's only a few mm, but it's a big donut area. And I'm sure I already posted on CSL style cooling inefficient design with semi floating pins.

Girodisc rotors are a much better design and have performed much better for me with their proper cooling and increased vane count (data points on pad wear, not boiling fluid, temp paint and/or stickers on rotors/pads/calipers, etc).

Sidenote for all, FCP now carries Girodisc rotors. You can't find them using category filters because you can only filter by left vs right and Girodiscs are sold as pairs, so do a keyword search. Word of caution and take it as you will, rotors last a lot longer than you think (think years), vs pads which need to be replaced every few track days.

Did Girodiscs solve my problem with broiled boots? No. Remember, pretty much everything goes south once you got your pads below 50%. And I got the full works at this point with no shield, cooling ducts, ti pistons, ti 1mm shims, Girodisc rotors, silicone boots, etc. I'm tired of swapping the boots, so I'll sit out on trying these .

Sent from my SM-S911U1 using Tapatalk

[OPS]

So who's gonna be the test subject for these?

Frenkit has been in the business a long time; Just not in the States. We used to buy from Centric but they went south and seems as though they took Stoptech with them. Maybe not. That's who we used to use when we made the brake brackets for the BBK's for so many back on M3forum.



(Spain TCR Cup)

Thanks for the welcome Ian! Glad to help the community out!

Mike