Speed2k

I take my car to the track from time to time. I want to use slotted rotors, instead of the cross drilled ones. I read through lots of threads and I want to save everyone some time and to make it easier to find info on upgrading rotor and pads for a 991.2 in a single post. I read through this thread (which has additional info for the 991.1) and this one to compile this info, so credit goes to the posters in there.

Note: base and Carrera T models have a different set-up in the front

Naturally there are other upgrades, including 2 piece rotors like Girodisc or AP Racing, or you could upgrade to a BBK. But for me, the tracks I attend are not hard on brakes, in addition, I'm slow and I just go to the track to have fun.

Anyhow, here are the part numbers and some additional notes:

Stock rotors for the 991.2 S/4S is 350 Front and 330 Rear, this mod will increase your rear rotor size to 350mm. You will need to add a spacer to the caliper and you'll need longer bolts (or you can upgrade to studs) to make everything fit.

Slotted Rotors:
350mm Front Left Sebro 909355C
350mm Front Right Sebro 909356C
350mm Rear Left Sebro 909383C
350mm Rear Right Sebro 909384C

Additional Notes:
Rear: This is a 997 Turbo 350mm rear rotor. 10mm longer bolts and spacer is needed, but you gain a 20mm larger rotor.

Pad Options:
DS2500 Ferodo FCP4664H (GT3 size) -Front
DS2500 Ferodo FCP4713H - Rear

Not available from FCP Euro but looks like ECS has them:
DS3.12 Ferodo FCP4664G (GT3 size) - Front
DS3.12 Ferodo FCP4713G (stock size) - Rear

Pagid Yellow RSL29s (PAG-4924-RSL29) -Front (GT3)
Pagid Yellow RSL29s (PAG-4909RSL29) -Rear (S/C4S)

Alternatives (not available from FCP Euro)
MX72 Endless EIP240 Front (GT3 size)

Additional Notes:
Front GT3 pads will fit, but rears will not, so don't buy those!

Caliper Studs Options* (not available from FCP Euro): 85mm front/95mm rear - if going to 350mm rotors (95mm is listed for 997.2 turbo)
Girodisc part numbers: BCS-05 front and BCS-03 rear
Tarrett part numbers: BCSK-85 front and BCSK-95 rear
*A reminder again, if you don't go with studs, you will need longer rear bolts.

Spacers (not available from FCP Euro):
@AdamSanta85 Who started one of the above thread, wrote this: Rear needed the 11mm spacers and longer bolts from Freddy's kit (lewisspeedinnovations@gmail.com)
Alternatively, spacers is also available through here.

Additional recommended upgrade:
A Tarett Brake line bracket stud kit, to make it easier to change pads.

Tier1Terrier

Thank you @Speed2k !!! It's like you were reading my mind when you created this thread. Thank you. Now for the questions...

I see in your notes "Front GT3 pads will fit, but rears will not". If they fit, is there a reason one would not want the GT3 sized pads for any of the brands?

For the Ferodo DS2500 pads that are available through FCP, I only see that it says "GT3 size". Is it that FCP does not carry a stock size Fedoro DS2500 or that Fedoro doesn't make one in the DS2500 for the front?

Moving onto the Ferodo DS3.12 that are not available from FCP. Here you have listed both GT3 size andr stock size for the front. The question (again) is why or why not just go with the GT3 size?? Are they bigger than the stock size? And if they fit the stock caliper and rotor, wouldn't it just make sense to go with those? Again, just trying to understand why one would not choose the GT3 size pads if they indeed fit without issue.

More questions for the total brake novice/newb...

Can you explain the whole studs vs bolts thing? Are we replacing factory/oem bolts with studs and why? Could you only replace the rear calipers bolts and leave the front ones original since you are not changing anything about the front brake dimensions, OR is it advisable that you change these bolts for every pad/rotor change (regardless). And if I understand correctly, the only reason we would need longer bots or studs for the rears is because we are going from 330mm rotors to 350mm rotors (with spacers). Just asking (rhetorically).

Lastly, Can you explain why changing the brake line bolts to studs makes changing pads easier?

Speed2k

Haha, yeah, I figured I wouldn't be the only ones that have these questions!

Good question! There's some info in this thread, if you want to read up on this stuff. On the Essex website, when I key in my car info the FCP4664H is the size listed, but on the FCP site, it doesn't list the 991.2 S/4S/GTS under the "Fitment" tab, but I'm pretty sure the Essex info is correct.

As for other brands? I think so (but I'm not 100% sure, so do your own research if you go with another brand) based on info posted here on the Pagid pads (from the post by @Nathan_ :

From the Pagid site, 4908 is for the S and 4924 is for the GT3.




The "4955G" was actually from the ECS site, I believe this info is incorrect now, so I'll remove it from the first post. The Essex website (and from other RL threads) says this pad size is actually for the 991.1 .

Where to start, lol. I numbered your questions off, so it's easier to follow along.

1. Studs vs Bolts: There are a couple of reasons, the factory bolts are supposedly one time use, so every time you change pads, you would need new ones. The other is to prevent wear and tear on your aluminum uprights from having to remove and reinstall bolts. Once the studs are in, you won't need the bolts anymore.
2. You could, but fronts probably will get replaced more than the rears, so it's probably advisable to do both.
3. Correct
4. The brake line is short, so the bolt needs to be removed each time; the brake line studs supposedly makes removing and reinstalling faster (+ less wear and tear).

4 Point 0

Just because something physically fits, doesn’t mean its ok.

Just because it says GT3, doesn’t mean its better.

You need to match the pad to your specific annulus.

Annulus is the distance between two circles.
In english the length of the additional radius measuring from the inside of the rotor to the outside of the rotor.

if the brake pad you select is not using the entire annulus, then it is not giving you full benefit. You will end up with a rusty unused section on your rotor.

GT3 have 380 front and rear. So unless you have a 380 rotor, and the same deep annulus, why on earth would you want to use that pad. Just so you can puff your chest out to say you use GT3 pads 🤣. You want your pads to work.

Stop half assing it. 🤣

Heat is your enemy. A 330 just does not have enough metal to dissipate the heat fast enough. As things heat up, it rapidly accelerates wear. So that money you thought you saved, just got burnt through in one track session.
Pads destroyed. Rotors badly grooved in the wrong shape.

Start over again. Money flushed down the toilet and problem still not fixed. This is your future.

How about you double your budget, get something half decent that will at least last a year instead of one track day?

If you want to slow down the wear, which in turn slows down the spending, you need to go big.

Dark_horse

When I was looking into upgrading brakes I also looked at all the solutions. In the end I wanted to spend my money once and got a proper BBK. So glad I did! Do it right the first time.

The difference in braking and feel is insane.

Tier1Terrier

@4 Point 0 Thank you for your input here. Your knowledge and experience on brakes are very appreciated. I don't think anyone wants to debate whether or not your recommendation for a 'proper' kit is the ideal long-tern solution for a track oriented driver. Your points are clear and well understood.

The problem here is that the FRONT Ferodo DS2500 pad that is recommended on the Essex website for a 991.2 Carrera S is Part #: FCP4664H-N. and the part number they recommend for a 2017 Porsche 911 GT3 is Part #: FCP4664H-N. It's the same part number.

On the FCP website, the same part number does not show fitment for a 991.2 Carrera S but it DOES show fitment for a 991.1 and 991.2 GT3. So what's consistent here is that both FCP and Essex agree that the part number Part #: FCP4664H-N is for the 991 GT3. FCP does not show it as fitting a 991.2 Carrera S. So either FCP is unaware that GT3 DS2500 pad also works for the 991.2 Carrera S OR Essex is selling the wrong part. The default wisdom seems to point to Essex not being wrong.

@4 Point 0 I agree that the pad needs to match the caliper & rotor. Essex seems to think that the FRONT pads for the GT3 and 991.2 Carrera S are the same. Maybe @JRitt@essex can chime in here and clarify.




.

SilverSFR

I’m not sure the goal here is for top notch track brakes. For me it would be the experience of a slight upgrade from stock brakes for the same ish price as replacing stock brakes. Pads and rotors need replace on all 911s sooner or later. Why not do this slight upgrade for the same price as an OEM pads and rotor replacement. And if you enjoy tinkering with your car as many on here do what’s the downside. The brakes are not going to be any worse than they came oem with. And from a layman perspective my oem brakes were pretty great. The only downside I see would be for future owners and independents going what the *&$#@ these are not oem.

JRitt@essex

Hi Tier1Terrier,
Thanks for tagging me! Yes, the FCP4664 is the correct shape for the 991.2 Carrera S. The 4664 shape is slightly different on the lower edge of the pad vs. the OEM pad, but that doesn't have any impact on fitment or performance. So for your 991.2 Carrera S, your shapes are:
Front= FCP4664
Rear= FCP4713

You can see our complete brake menu for your car here:
https://www.essexparts.com/my-vehicl...0S/Iron%20disc

Let me know if you run into any other issues.

thesaintusa

@4 Point 0

If you were to recommend a brake set up that was not as extreme as your set up, for people that are not as fast at the track as you, what would you recommend?

thesaintusa

@Tier1Terrier

Agree that this is a common issue. When buying Endless pads, the front size option for a 991.2 GTS was the GT3 pad. I can confirm they fit, but cannot confirm how the rotor will wear (as per @4 Point 0 ).

Like others I am wanting to upgrade the brakes, but not sure which kit to go with.

4 Point 0

Size matters. Heat is the enemy. The more mass, the faster they cool.

Brembo have a full range.

My son has always ran Brembo GT. He is as hard on the equipment as I am, ans they have served him well. He runs 405 up front, 380 rear.

I went one higher with Brembo GTS as it doesn’t have the outer seals that crack and melt first track day. I only cooked the coating as the rotors were shallow annulus, not the deep annulus Hi-thermal ones i run now. Not all 380’s are equal. The calipers were epic, its just they discoloured. I cooked the OEM calipers as well. I haven’t cooked the new nickel ones yet, but the painted logo has left the building 🤣.

Either of these two are more than enough paired with 380 rotors front and rear.

Alternatively the AP kit that has 372 front and rear is also a solid choice.

For those wanting even more AP have a 390 front that's 36mm thick, and I now run Brembo’s top of the range GT-R kit.

1. decent sized rotors front and rear.
2. Better pads - ME20 great all rounder.
3. Most BBK come with braided lines
4. Decent fluid - Castrol SRF or Endless RF650

Calipers will come down to intended use. The great thing is, you can’t go too far with a big brake kit. You can go too far. With pads. But that's an easy fix. Drop back a level next time. No one has ever said, I went too big on brakes.
Assuming they fit under wheels of course.


If you go too small, then track, the wear rates accelerate to unacceptable levels. You shouldn’t be fitting new pads before and after one track day. The bigger you go, the longer they last. The faster they get rid of the heat, and therefor slow down wear.

thesaintusa

Glad that you think the AP 372 kit is a worthwhile upgrade.

Looking to go with a 19" wheel set up, and the 372 kit would fit.

Appreciate your input!

JRitt@essex

We have 1,000 HP C7 ZR1 track cars successfully running our 372mm AP Racing by Essex Radi-CAL Competition brake kits. Size matters, but so do the materials and the design. Please check out our blog to see lots of very fast, well-driven cars running our system. Some of these are being driven in full wheel-to-wheel endurance racing events, not just HPDEs. The Essex Blog: https://www.essexparts.com/news-blog

Here's an example of a 700 WHP 991 Carrera T who found our 372mm system to be the perfect solution: https://www.essexparts.com/news-blog...tion-brake-kit

Tier1Terrier

@JRitt@essex Can you explain what would make the Radi-Cal Competition 372/365 Brake Kit 'better' than the Road 380/380 kit? They are pretty close in price when you consider both the front/rear together. What's easy to see is that the discs on the Radi-cal kits are 2mm thicker all around, so I'm assuming the calipers might be different too in order to accommodate the thicker rotors. But is there more to it than that?

JRitt@essex

Our Road and Competition Kits are two ways to accomplish the same task, which is greater heat capacity. I like to refer to them as the sledgehammer (Road Kits) vs. scalpel (Competition Kits). The Road Kits uses huge discs and pads to store heat, whereas the Competition Kits rely more on materials and design to keep pad and disc temperatures down. Have you ever seen this page on our site?

Which Type of AP Racing Brake Kit is Right for Me? https://www.essexparts.com/big-brake...-right-for-you

Both kits are incredibly effective. It just depends on how you're using your car and what you're trying to achieve. We have lots of 991 owners on both types of kit at this point, and everyone loves whichever one they chose. The good news is that regardless of how you plan to use your car, we have you covered!