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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Fri Dec 29, 2023 7:42 am Post subject: Making adapters for Boxster brembo calipers |
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Hi
Im doing a little side project while waiting for parts to finish my engine stuff. Not that im in direct need, Ive had the std brakes work well on track, and could step up a few levels in pad compound with the new power level. But instead Im doing this, mostly for fun, but also to be able to run less hardcore compounds since its also a road car, and still handle the heat.
The choice is 4 piston Boxster front calipers from the non S, they have pretty much exactly the same piston area as the original calipers, so no shift in balance. the plan is to combine them with the Carrera 3.2 discs, which are 24mm wide, instead of 20,5. That will also give some additional heat capacity. I hope i can still fit with 15" wheels with these ones, thats the plan.
Weight wise they weigh ca 3.2kg complete with pads, i couldnt weigh the std caliper since it maxed my little scale at 5kg. So even with adapters and heavier discs it will cut some weight.
Im fine tuning the fitment now, and waiting for brake discs (cost me about 65usd /each, so very reasonable. when the discs arrive i will conclude the design and order them machined.
Btw, they will be sturdy fairly heavy pieces made of steel, i dont want to rely on treads in aluminum on a track car.
Anyone else interested in a set? Could be fun to get someone else on the project
_________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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Mclaren924
Joined: 13 Oct 2021 Posts: 171 Location: California
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Posted: Fri Dec 29, 2023 2:33 pm Post subject: Re: Making adapters for Boxster brembo calipers |
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Cedric wrote: | Hi
Im doing a little side project while waiting for parts to finish my engine stuff. Not that im in direct need, Ive had the std brakes work well on track, and could step up a few levels in pad compound with the new power level. But instead Im doing this, mostly for fun, but also to be able to run less hardcore compounds since its also a road car, and still handle the heat.
The choice is 4 piston Boxster front calipers from the non S, they have pretty much exactly the same piston area as the original calipers, so no shift in balance. the plan is to combine them with the Carrera 3.2 discs, which are 24mm wide, instead of 20,5. That will also give some additional heat capacity. I hope i can still fit with 15" wheels with these ones, thats the plan.
Weight wise they weigh ca 3.2kg complete with pads, i couldnt weigh the std caliper since it maxed my little scale at 5kg. So even with adapters and heavier discs it will cut some weight.
Im fine tuning the fitment now, and waiting for brake discs (cost me about 65usd /each, so very reasonable. when the discs arrive i will conclude the design and order them machined.
Btw, they will be sturdy fairly heavy pieces made of steel, i dont want to rely on treads in aluminum on a track car.
Anyone else interested in a set? Could be fun to get someone else on the project
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Very interested in a set for my 77 Restoration that I want to 5 lug swap. _________________ 1980 931 "Salt" Bucket wannabe racer (not started)
1979 924 "Pepper" Restoration (almost done)
1980 924 "Donnie" (Parts car)-DEAD
1977 924 Slicktop "Pennie" Bucket turned Silver Spoon |
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morghen
Joined: 21 Jan 2005 Posts: 8868 Location: Romania
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Posted: Fri Dec 29, 2023 6:27 pm Post subject: |
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I need to check my disks and pads condition, if i need to replace them i'll also want a pair of adapters. _________________ https://www.the924.com |
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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Sat Dec 30, 2023 11:33 pm Post subject: |
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Work has been progressing, and protoypes has been tested, adjusted and tested again, its very small changes to get everything perfectly centered up. And I also got my 24mm discs, so i could sort out the final measurments.
Pretty happy with the location of the caliper now, so I think im gonna work a bit on the design to prepare for ordering of the steel ones.
The thicker discs has significantly more flow are in the cooling ducts, this looks vert promising for the heat management.
20,5 vs 24mm disc
difference in cooling channels
with the thicker disc installed
_________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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Joma
Joined: 28 Nov 2016 Posts: 18 Location: Netherlands
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Posted: Sun Dec 31, 2023 5:34 am Post subject: |
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sign me up
i got a set of calipers left over from my 987 that i upgraded to 330mm.
any plans for the rear brakes? _________________ 924 80 with 931 S2 engine and efi |
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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Sun Dec 31, 2023 7:52 pm Post subject: |
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Joma wrote: | sign me up
i got a set of calipers left over from my 987 that i upgraded to 330mm.
any plans for the rear brakes? |
Just had a quick google and the base Cayman seems to have the same calipers as the base 986 Boxster, so it should work.
Regarding the rear brakes i have no plans, theres much less thermal load on them, would be nice to shed some weight though, but finding a fancier caliper with such a small caliper area is not so easy. Balance is important for me since im performance oriented, dont want to make the braking worse than the std system:) a re route of the braking system to f/r and reducer valve for the rear would of course make it easier to find calipers, but i want to keep it simple.
Caliper part numbers:
986351422
986351421 _________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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Carrera RSR
Joined: 08 Jan 2010 Posts: 2309 Location: Somerset, UK
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Posted: Wed Jan 03, 2024 11:16 pm Post subject: |
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Isn't there one or two bolt on 944/968/Boxster Brembo solutions for the rear of a 931? I can't recall exactly without searching, but it was always the front where mounting needed a 944 hub or mounting adapters.
But, if you have lost decent weight out of the rear, the stock rear caliper easily locks up before the fronts on my car.....especially trail braking which once used to the movement helps pivot the car in sharper corners. _________________ 1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252 |
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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Thu Jan 04, 2024 12:08 am Post subject: |
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Carrera RSR wrote: | Isn't there one or two bolt on 944/968/Boxster Brembo solutions for the rear of a 931? I can't recall exactly without searching, but it was always the front where mounting needed a 944 hub or mounting adapters.
But, if you have lost decent weight out of the rear, the stock rear caliper easily locks up before the fronts on my car.....especially trail braking which once used to the movement helps pivot the car in sharper corners. |
I haven't found much on the rear that have close to the right piston area, almost every caliper has to much of it, maybe if i used a different front caliper. The boxster/cayman one is the same area as the std caliper up front, which is one of the reasons i chose it, and the compact size. 2 piston 36mm Brembos from an impreza sti would have the same area though as the std ones But its not something i will look at now. At the moment im finalising the order of two sets, one for me and a spare set for someone that wants to try them
I found std brake bias to work very well, and i always trail brake deep to the apex, Hence i want to keep the balance as it is and not shift it, according to logs my braking looks really good compared to other similar track cars,. i hope it will continue like that _________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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barnwerks
Joined: 28 Oct 2022 Posts: 17 Location: Northeast and southeast US
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Posted: Thu Jan 04, 2024 3:49 am Post subject: |
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I am also interested in a set of these adapters. Do you have an estimate of cost? Are you willing to ship to US? |
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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Thu Jan 25, 2024 7:43 pm Post subject: |
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The parts just arrived from machining, made in steel with nickel plating. Everything seem to line up great. So time to gets some proper pads and put everything together. The fitment with cookie cutters 15" for example still needs to be checked. I have some 15" BBS wheels around aswell that i could try. With some help of a friend we did some half decent FEM calculations, and updated the design to be sure they outlast me and the car
The spare set might be up for grabs if someone have plans to try this mod, and could drive their car sooner than i can drive mine
_________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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morghen
Joined: 21 Jan 2005 Posts: 8868 Location: Romania
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Posted: Thu Jan 25, 2024 11:43 pm Post subject: |
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These look amazing! And really cool with those cutouts in the midle. _________________ https://www.the924.com |
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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Fri Jan 26, 2024 12:04 am Post subject: |
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morghen wrote: | These look amazing! And really cool with those cutouts in the midle. |
It was a good way to cut some weight, but I also did it for them to look cool just for fun _________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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Mike9311
Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish
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Posted: Fri Jan 26, 2024 3:23 am Post subject: |
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Cedric wrote: | morghen wrote: | These look amazing! And really cool with those cutouts in the midle. |
It was a good way to cut some weight, but I also did it for them to look cool just for fun |
Sooo nice!! This is why I come here. There are more of us out there
Really nicely done. They look wicked! _________________ 1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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Joma
Joined: 28 Nov 2016 Posts: 18 Location: Netherlands
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Posted: Sat Jan 27, 2024 8:54 pm Post subject: |
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Cedric wrote: | The parts just arrived from machining, made in steel with nickel plating. Everything seem to line up great. So time to gets some proper pads and put everything together. The fitment with cookie cutters 15" for example still needs to be checked. I have some 15" BBS wheels around aswell that i could try. With some help of a friend we did some half decent FEM calculations, and updated the design to be sure they outlast me and the car
The spare set might be up for grabs if someone have plans to try this mod, and could drive their car sooner than i can drive mine
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They look really nice.
i still want them, but i will be a while before i can test fit them
currently working on the outside of the car.
and need to have the callipers rebuild and repainted.
so i want them but cant immediately fit them _________________ 924 80 with 931 S2 engine and efi |
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Cedric
Joined: 27 Aug 2004 Posts: 2600 Location: Sweden
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Posted: Sun Jan 28, 2024 8:05 am Post subject: |
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Joma wrote: | Cedric wrote: | The parts just arrived from machining, made in steel with nickel plating. Everything seem to line up great. So time to gets some proper pads and put everything together. The fitment with cookie cutters 15" for example still needs to be checked. I have some 15" BBS wheels around aswell that i could try. With some help of a friend we did some half decent FEM calculations, and updated the design to be sure they outlast me and the car
The spare set might be up for grabs if someone have plans to try this mod, and could drive their car sooner than i can drive mine
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They look really nice.
i still want them, but i will be a while before i can test fit them
currently working on the outside of the car.
and need to have the callipers rebuild and repainted.
so i want them but cant immediately fit them |
What wheels do you intend to use?
Today I had some wheel fitting tryout, i tried 15" BBS mahle, 16" Fuchs (Maxilite), 16" D90. The BBS wheels and especially D90s had plenty of room. the Fuchs were much tighter now that i moved the caliper out to accommodate the wider brake disc, but it fits, i just have to relocate the balancing weights to be sure they doesnt touch _________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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