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

[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.


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[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 .

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[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

[SQ13]

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?

[heinzboehmer]

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

Sounds like it's your turn

Have a fresh set of girodisc boots that I'm gonna swap in before the next track day to try and quantify the effectiveness of the Bryson scoops. If they don't survive, the OPS ones are next on the list.

[Obioban]

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

[OPS]

First Pistons arrived! I'll get the details up on the web hopefully this weekend..

28/30
28/32
30/34/38
30/32/34
32/32
34/36/38
34/34
36/40
36/44
40/44
44/44

[OPS]

Just the beginning… I just wish we would have kept all of our research back then. good times.

[Obioban]

Nice.

[OPS]

After over four years of searching for a company to produce high-quality alternatives to the brake caliper rebuild scene, We are pleased to announce a partnership with Frenkit S.L. out of Navarra, Spain, who agreed to start a new performance product line to cater to the motorsport community.

At the onset of 2019, continuing well into the COVID era, we began to see the quality control, materials composition, and packaging of “high temperature” caliper rebuild kits becoming subpar. Thus began our mission to find a manufacturer who would produce the products we and the motorsport community needed. Many manufacturers refused to meet with us as; however, in 2021, a company based out of Spain reached out with an inquiry to expand its product offerings in the US market.

All Frenkit Performance silicon boots have a temperature range of -40°C to +300°C compared to EPDM temperature range of -40° to +160°C.

Rebuild kits to include pistons should be here in a week.

Nice to be back.

Mike

[Nate047]

I started going back through this topic from the beginning. For context I followed Ian's link to Ohio Performance Solutions, and it looks like something has changed in the last year. Anyone ever heard of this manufacturer? https://www.ohioperformancesolutions...-rebuild-parts

Someone needs to contact them because they were out of stock for a long time. Not sure if that’s a new/different supplier.

[D-O]

Nobody has heard of Frenkit? If their claim is true 300 C seems pretty stout - how hot do the pistons get?

[D-O]

I started going back through this topic from the beginning. For context I followed Ian's link to Ohio Performance Solutions, and it looks like something has changed in the last year. Anyone ever heard of this manufacturer? https://www.ohioperformancesolutions...-rebuild-parts