golfnutintib

Question for the gear heads among us...

Does anyone know what is the actual unsprung weight differential at the front and rear for a 991 GT3 equipped with factory ceramic vs. steel brakes?

I know that like for like, the ceramic setup are a good bit lighter, but then again on the GT3 the ceramic rotors are a larger diameter than the steels, correct? So the actual weight difference of the rotor/caliper/pad setup may be less than one might think...

I am thinking through the brake option question for my GT4 order, thinking through this angle.

Anyone here really know? Thanks in advance...

Mike in CA

One of our RL forum brake sponsors recently posted actual measured weights comparing OEM ceramic rotors to their own ceramic replacements to OEM cast iron rotors. IIRC, the difference between the cast iron front rotors and the OEM ceramics was close to 10 pounds, despite the ceramics 30mm larger size. I'd expect at least a similar difference between the rears which are only 10mm larger in diameter for the ceramics. Maybe someone remembers the specific thread.....

golfnutintib

mike - 10 lb PER ROTOR? must be even greater in the rear...

Jimmy-D

I am going to go with PCCBs for my GT4. Why??? - Color schematic will look good with Carmine Red and yellow stitching. Also - It is going to be for the road only and I want to see if I can truly tell the difference.(Going to see/confirm what Mike has been preaching for awhile )

GrantG

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golfnutintib

It's a tough call for me on the choice since the GT4 is a pretty light car, and I have never on any of my Porsche's since my 993 where I felt the standard steel brakes weren't up to the task, even flogging on track days.

However, I definitely can feel the difference in reducing unsprung weight once I change wheels or add BBK on any performance car I have owned. Lower unsprung weight really helps the car feel more nimble AND more powerful... and the difference isn't subtle.

This plus the high cost of replacing PCCB rotors when it comes time...

GrantG

Racingbrake.com have said that they can refurbish PCCB rotors for $400/rotor. I don't know how well this works, but this gave me cause to reconsider the issue (never wanted anything to do with PCCB's til I heard that). That is about 10% of the replacement cost (when bought on sale).

alaint101

I vaguely remember. However, I thought this was 'their' rotor delta, which was deemed lighter than OEMs. Of course, I could be wrong. I say this because I have had a separate exchange on the matter w/ the dealer. On the 997, the combined delta was 26lbs unsprung weight saving overall. 40+ seems optimistic.

orthojoe

How can you refurbish a rotor that is laminated? A solid CCB rotor can be refurbished, but Porsche has never made a solid CCB rotors, only laminated to my knowledge.

GrantG

Only passing along info that was posted by Racingbrake - I can't vouch for the possibility or performance...

Sloopy

I have ceramics on mine and I feel the weight difference. Especially over a bumpy road because the ride is better. Notable they are expensive but for myself I feel the expense is offset by the benefit.

It is also noticeable every time I apply the breaks at higher speeds. First part of break applications goes to dissipating kinetic energy stored in each wheel. The higher the speed the more stored energy that has to be overcome. 40lb makes a huge difference in this.

orthojoe

I PM'd RB to clarify. I think people are confusing the ability to refurb OEM rotors vs surface transform rotors

golfnutintib

yes i think you are right joe -- 400 bucks to redo ccb rotors is way too good to be true

btw - you going to laguna seca for tomorrow's run w HOD?

GrantG

Appreciate any info you learn. I was pretty sure he said they could refurb their own rotors, but also the stock PCCB's. But, I could be wrong...

orthojoe

Found this post by RB today:

https://rennlist.com/forums/991/8460...l#post12071652

They are referring to ST rotors, NOT OEM.

Yeah, no way OEM rotors can be refurbished if they are laminated.
No MRLS for me until I get some sound pipes made. I hope to have a set to test in May. I'll be at Thill with HOD on 3/13 though.