900fc

I currently have a steel brake on my 991.2 GT3 and interested to put PCCB rotors. Has anyone done this conversion going from steel to PCCB with retaining OEM red calipers that I prefer to the yellow ones using spacers between knuckles and caliper to compensate the difference of diameter of the rotors?

Front:
Steel rotor: 380mm * 34mm
PCCB rotor: 410mm * 36mm
spacer of 15mm?
Is the brake pad thinner on PCCB versus steel but can fit same caliper and caliper can clear larger radius of rotor?

Rear:
Steel rotor: 380mm * 30mm
PCCB rotor: 390mm * 32mm
spacer of 5mm?
Is the brake pad thinner on PCCB versus steel but can fit same caliper and caliper can clear larger radius of rotor?

Thanks for the feedback if you have done it. I know Surface Transforms sells their kits for steel brake with spacers and new bolts. I am looking at using OEM Brembo PCCB on my car.

Thanks,
Cedric

Thrownaway

Why do you want to do this?

johnsopa

Cedric, I think that converting from steel to PCCB is doable. There are a few threads on similar projects.

https://rennlist.com/forums/991-gt3-...i-rollbar.html

I believe that Soul and also Hinz can sell you the spacers and brake lines. I'd suggest getting Tarett caliper studs, too.

We love PCCBs on our cars, no dust, great on street as well as track.

900fc

Thank you John and the link you share is very helpful. I will reach out to Soul or Hinz. I looked at SF and RB as new solution but I might be able to get an OEM set of PCCB rotors at competitive price.

Thank you for your feedback

montoya

There are definite advantages to PCCB's, including unsprung weight, longer life (untracked), almost no dust and some slight braking performance advantages. In my case since I don't track my street cars, these advantages at the takeoff price I was able to purchase them for are worth it to me. If I tracked my GT3 I would not do this, but for the street this is a nice upgrade.

I was fortunate to find a takeoff set with the PCCB calipers and brake lines. Bought Tarett studs for the conversion- will be a fun weekend project soon.

Hinz Motorsport

Hi Cedric,
Regarding calipers, they are effectively the same and accept the same pad shapes and thicknesses. PCCB pad shapes drop right into the iron calipers. To note, unless you are sourcing a used set of PCCBs that are verified in good condition and favorably priced, I think the Surface Transforms Iron Upgrade kit makes the most sense. As you know they already have a kit to use your red calipers with carbon discs. STs are superior, refurbishable, and way cheaper in comparison to buying new PCCBs. That said, if you really want PCCB discs, I can source the hardware for you -I may have some extras lying around. I also have a few Surface Transforms 991 GT3/RS iron upgrade kits on the shelf. Regardless of which option you choose, I would recommend the Pagid RSC1 compound for pads. Works great with STs and PCCBs. Feel free to call or pm if you'd like to chat.

Thanks,

Vinh Nguyen

So I currently have Steel Rotors on my 991.2 GT3 and just bought from someone locally a set of PCCBS with Pads.

What are all the parts you need to do the conversion? New Bolts? Pad sensors? PCCB sized calipers?

900fc

I appreciate your response. If I am buying new, I would go without hesitation with SF kit with I believe is superior that OEM PCCB. I just don’t think I can justify putting $12-14k in a new kit so looking for an used in good condition at $6-7k max otherwise I will stay with steel rotors.

Airbag997

Isn't the master cylinder different and or the tuning PCCB vs Cast-Iron?

Hinz Motorsport

You will need 15mm front spacers and 5mm rear spacers and the PCCB length bolts. The pad wear sensors should be the same between both models, but someone can fact-check me on that. Your calipers will take the same pad shapes. When you remove your iron pads to install the PCCB pads, hold them next to each other and you will understand why/how it works. The calipers are the same as the PCCB calipers, but the mounting "legs" on the PCCB calipers are longer to accommodate larger discs. The castings are the same, just the legs are machined differently. You would also need the longer front brake hardlines: p/n 991-355-581-81 & 991-355-582-81

Yes totally understandable. I just like to make sure folks are aware when looking for used or new replacement PCCBs, as this is a better solution and can be cheaper.

No tuning is required. The calipers and piston sizes are identical, so you are pushing the same amount of fluid at the master cylinder. You could argue the friction levels/characteristics of iron-based pads differ from that of PCCB, but you have thousands of owners going from street compounds to race compounds and they are not messing with the master cylinders in the process. Hope that makes sense?

Airbag997

Yeah, makes sense if calipers are identical. Thanks.

flsupraguy

Check out my listing:

$4,500 Refreshed 991 GT3 PCCB Calipers w/ BRAND NEW GiroDisc Iron Conversion Rotors 410/390

https://rennlist.com/forums/market/1341997

jbatchelor

Except that Porsche have gone to the trouble of developing different ABS algorithms for steel and carbon-ceramic rotors.

Up-to the point of ABS activation, I guess it's all the same and controlled by your foot but, beyond the point of ABS activation, best to have the appropriate ABS system response, I think. It isn't a coding action as such (no new codes are required); it's more of a software 'toggle' that selects between steel and carbon-ceramic ABS settings. Just requires a quick PIWIS hook-up to switch-over the appropriate setting. My dealer charged me all of 15 minutes labour to do this. Helps keep insurance issues at bay, too.

James

900fc

Thanks James, I have a PIWIS and wasn’t aware the ABS setup was different.👍

Palting

I've been lurking this thread, decided to chime in.

I've had 2 991.2 GT3s. The first had iron brakes, the current one has PCCBs. I track a lot, so I recently swapped out the PCCBs for Girodisc. Keeping the PCCB units for when I eventually sell the car.

Yes, the PCCB's have an interesting initial bite. Yes, the PCCB,'s generate less dust. Yes, the PCCB's are significantly lighter. Yes, the PCCB rotors can last almost forever if used only on the street. Yes, the PCCB's have bragging rights with the yellow calipers.and the $25K price tag.

Is it worth replacing your iron brakes for them though? My personal answer is no.

Porsche males excellent brakes, and the iron brakes are excellent. If your wheels have too much brake dust, it's time to wash the whole car anyway. Unless you are the driving caliber of Hamilton or Verstappen, you won't be able to tell the performance difference from the weight of the rotors. With the cost savings on replacing iron rotors, is is still probably cheaper than replacing the PCCB rotors over time. That would leave bragging rights, but you are keeping the red calipers so that sort negates that, but maybe not really.

Sorry, not much help to you based on your original question, that's why I only lurked initially. But now maybe I can help by questioning your decision to swap? .