Brake upgrade
Burning Brakes
Joined: May 2021
Posts: 765
Likes: 441
Usually, when you upgrade to larger rotors and different calipers, the mounting hardware is different, the caliper is further from the center of the disk. Most upgrade kits include the appropriate brackets. The standard Carrera brakes are well matched to the car, but they do lack the wheel filling look of the S brakes, and the GTS brakes or PCCB are even more imposing.
Instructor
Joined: Jul 2023
Posts: 101
Likes: 46
As many will voice, OEM pads are useless for track days for all but the 'greenest' of drivers, and are the absolute first/cheapest/easiest option to upgrade. Did you really ‘warp’ a rotor, or are you sure you didn’t just glaze the pads or leave deposits on the rotors?
In any case, seems like you want to spend $$$ on the car for visual upgrades, but trying to disambiguate ‘want’ from true mechanical ‘need'? My strong recommendation is to start with a pair of track-speck EBS/Pagid/Hawk etc - guessing that will get you 95% of the way...
In any case, seems like you want to spend $$$ on the car for visual upgrades, but trying to disambiguate ‘want’ from true mechanical ‘need'? My strong recommendation is to start with a pair of track-speck EBS/Pagid/Hawk etc - guessing that will get you 95% of the way...
If we can easily (and cheaply) have OEM GT4 380mm rotors and keep our 6 pot C2S calipers - why not make that upgrade? Seems like a no-brainer to me especially when time comes to swap rotors. The additional surface area and heat dissipation would be a welcome addition along with filling in the wheel and let's admit it - who doesn't like big rotors behind the wheel??
Instructor
Joined: Jul 2023
Posts: 101
Likes: 46
Racer
Joined: Sep 2022
Posts: 319
Likes: 196
Also remember that putting in bigger rotors means more weight in a place you dont want. Ide also upgrade the pads as the first order of business and go from there. If this is for esthetics, well cough up the $ then.
Rennlist Member
Joined: Oct 2012
Posts: 1,695
Likes: 1,918
From: Boston, MA
>> The additional surface area and heat dissipation would be a welcome addition along with filling in the wheel and let's admit it - who doesn't like big rotors behind the wheel??
"Never go a day without a rationalization". If this were truly a 'thing' then enterprising vendors like Flat6 would be selling a shim/upgrade kit, but they aren't. Meanwhile messing with the *single most* important safety system on the car by fabricating a sketchy aluminum shim for the most heat-critical area seems like a truly bad idea, and there's no way any PCA tech inspector would approve that configuration. Either spend the $$$ to do it right or not at all.
"Never go a day without a rationalization". If this were truly a 'thing' then enterprising vendors like Flat6 would be selling a shim/upgrade kit, but they aren't. Meanwhile messing with the *single most* important safety system on the car by fabricating a sketchy aluminum shim for the most heat-critical area seems like a truly bad idea, and there's no way any PCA tech inspector would approve that configuration. Either spend the $$$ to do it right or not at all.
Last edited by jlegelis; Nov 7, 2023 at 12:00 PM.
Instructor
Joined: Jul 2023
Posts: 101
Likes: 46
>> The additional surface area and heat dissipation would be a welcome addition along with filling in the wheel and let's admit it - who doesn't like big rotors behind the wheel??
"Never go a day without a rationalization". If this were truly a 'thing' then enterprising vendors like Flat6 would be selling a shim/upgrade kit, but they aren't. Meanwhile messing with the *single most* important safety system on the car by fabricating a sketchy aluminum shim for the most heat-critical area seems like a truly bad idea, and there's no way any PCA tech inspector would approve that configuration. Either spend the $$$ to do it right or not at all.
"Never go a day without a rationalization". If this were truly a 'thing' then enterprising vendors like Flat6 would be selling a shim/upgrade kit, but they aren't. Meanwhile messing with the *single most* important safety system on the car by fabricating a sketchy aluminum shim for the most heat-critical area seems like a truly bad idea, and there's no way any PCA tech inspector would approve that configuration. Either spend the $$$ to do it right or not at all.
The goal of this is to keep the OEM caliper as it's enough for my application but see if I can increase the rotor size. I think if enough people would be interested in a modification of this sort, someone will end up developing it and it would be beneficial for us all.
Do we absolutely need it? No. But we also don't absolutely need a 911 either
Drifting
Joined: Jan 2015
Posts: 2,052
Likes: 1,932
From: Pasadena, CA
This isnt 100% true. The AP Racing 372mm track package is a few lbs lighter than the factory 991.2 330mm brakes they replace. Thats a significant upgrade in brake while also shedding weight in an area where it matters most.
Instructor
Joined: Jul 2023
Posts: 101
Likes: 46
In this case, the GT4 380mm rotor weighs the same as the C2S 350mm - both are about 25 pounds.
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Verdad Gallardo
10 Porsche Colors That Have More Personality Than Most People
Verdad Gallardo
Guntherwerks' Final Speedster Creation Is the Ultimate Porsche Restomod
Verdad Gallardo
10 Reasons I Hate Going to the Porsche Dealership (& the 1 Reason I Stay)
Joe Kucinski
Porsche Shakes Up The Nürburgring Lap Record Table Once Again
Verdad Gallardo
6 Ways the Porsche 911 GT3 S/C Redefines Performance
Joe Kucinski
10 Wildest Homologation Specials Porsche Ever Sold
Verdad Gallardo
Super Rare RUF BTR III Comes Out of Hibernation, Looking For a New Home
Verdad Gallardo
10 Porsche Opinions That Can Start a Fight
Joe Kucinski
Rennlist Member
Joined: Jun 2023
Posts: 326
Likes: 335
Bumping this thread as it seems not many S owners have pursued upgrading to 380mm rotors instead of the OEM 350mm rotors.
Based on the information in this thread and a thread over from the 991 forum https://rennlist.com/forums/991/1434...-on-s-gts.html it's clear that 991.2 GT3 (IRON) / GT4 rotors will work. Where I am stumped is the ET difference in the rotors. The 991 thread doesn't mention an ET spacer needed on the hub, but this thread does, although it doesn't show a picture of it, only the caliper spacer.
The height of the rotor difference is 0.4mm. Hardly enough to warrant a spacer on the hub (if they even make such a thin one) so I'm curious what @pietrostone ended up using.
69.4mm height for the GT3 / GT4 380mm disc vs 69mm height for the 992 S 350mm disc
For the rears it's a 1mm negative difference in height and 2mm increase in disc thickness. (see 991 thread post #32)
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
This would be a very good improvement in weight, rear brake cooling (since the disc is 2mm wider, and overall braking performance (about 10%). I need to replace rotors anyways so this is a great excuse to upgrade with the paragon discs. Just need to figure out the spacers and do the washers for the pad studs as mentioned in the 991 thread towards the end. Curious if after a few years anyone else has done this upgrade and how you did it.
Based on the information in this thread and a thread over from the 991 forum https://rennlist.com/forums/991/1434...-on-s-gts.html it's clear that 991.2 GT3 (IRON) / GT4 rotors will work. Where I am stumped is the ET difference in the rotors. The 991 thread doesn't mention an ET spacer needed on the hub, but this thread does, although it doesn't show a picture of it, only the caliper spacer.
The height of the rotor difference is 0.4mm. Hardly enough to warrant a spacer on the hub (if they even make such a thin one) so I'm curious what @pietrostone ended up using.
69.4mm height for the GT3 / GT4 380mm disc vs 69mm height for the 992 S 350mm disc
For the rears it's a 1mm negative difference in height and 2mm increase in disc thickness. (see 991 thread post #32)
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
This would be a very good improvement in weight, rear brake cooling (since the disc is 2mm wider, and overall braking performance (about 10%). I need to replace rotors anyways so this is a great excuse to upgrade with the paragon discs. Just need to figure out the spacers and do the washers for the pad studs as mentioned in the 991 thread towards the end. Curious if after a few years anyone else has done this upgrade and how you did it.
Rennlist Member
Joined: Dec 2009
Posts: 536
Likes: 569
From: CA
I have a C2S, I get some warping during track days and that's probably due to the fact that I'm on OEM pads. But besides the fade, if we can easily swap to 380mm rotors up front, why not do so? Not only will it dissipate heat better, but it will fill in the wheels much nicer as well.
The stock caliper is beefy and does the job, but I think a bigger rotor will complete this package.
Not to mention how easy it would be to retrofit with those spacers.
The stock caliper is beefy and does the job, but I think a bigger rotor will complete this package.
Not to mention how easy it would be to retrofit with those spacers.
Rennlist Member
Joined: Dec 2009
Posts: 536
Likes: 569
From: CA
Bumping this thread as it seems not many S owners have pursued upgrading to 380mm rotors instead of the OEM 350mm rotors.
Based on the information in this thread and a thread over from the 991 forum https://rennlist.com/forums/991/1434...-on-s-gts.html it's clear that 991.2 GT3 (IRON) / GT4 rotors will work. Where I am stumped is the ET difference in the rotors. The 991 thread doesn't mention an ET spacer needed on the hub, but this thread does, although it doesn't show a picture of it, only the caliper spacer.
The height of the rotor difference is 0.4mm. Hardly enough to warrant a spacer on the hub (if they even make such a thin one) so I'm curious what @pietrostone ended up using.
69.4mm height for the GT3 / GT4 380mm disc vs 69mm height for the 992 S 350mm disc
For the rears it's a 1mm negative difference in height and 2mm increase in disc thickness. (see 991 thread post #32)
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
This would be a very good improvement in weight, rear brake cooling (since the disc is 2mm wider, and overall braking performance (about 10%). I need to replace rotors anyways so this is a great excuse to upgrade with the paragon discs. Just need to figure out the spacers and do the washers for the pad studs as mentioned in the 991 thread towards the end. Curious if after a few years anyone else has done this upgrade and how you did it.
Based on the information in this thread and a thread over from the 991 forum https://rennlist.com/forums/991/1434...-on-s-gts.html it's clear that 991.2 GT3 (IRON) / GT4 rotors will work. Where I am stumped is the ET difference in the rotors. The 991 thread doesn't mention an ET spacer needed on the hub, but this thread does, although it doesn't show a picture of it, only the caliper spacer.
The height of the rotor difference is 0.4mm. Hardly enough to warrant a spacer on the hub (if they even make such a thin one) so I'm curious what @pietrostone ended up using.
69.4mm height for the GT3 / GT4 380mm disc vs 69mm height for the 992 S 350mm disc
For the rears it's a 1mm negative difference in height and 2mm increase in disc thickness. (see 991 thread post #32)
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
https://paragonbrakes.com/paragon-2-...91-gt3-gt3-rs/
This would be a very good improvement in weight, rear brake cooling (since the disc is 2mm wider, and overall braking performance (about 10%). I need to replace rotors anyways so this is a great excuse to upgrade with the paragon discs. Just need to figure out the spacers and do the washers for the pad studs as mentioned in the 991 thread towards the end. Curious if after a few years anyone else has done this upgrade and how you did it.
Be prepared to swap or reshape the rigid brake lines when moving the calipers out radially on any swap.
Low miles/low wear take-off kit from a forum contact made it very affordable.
Amazing for feel, bad for unsprung and rotating weight. But I think 99% of people won't feel any difference, amateur car drivers often call out their love for initial bite as "good brakes" and that's not changing with huge brakes, people can just get different pads for initial bite.
Made lighter wheels to offset a little weight, eyeing CTE 410/380mm 2-piece carbon rotors next (they fit the GTS caliper setup).
Last edited by REVS11; Sep 15, 2025 at 09:20 AM.