MaxTheNomad

Hi all. I figured there could be more people with PFC brakes here in GT3/RS community, and therefore better chance of getting information about this.

Recently I got a caliper upgrade with PFC ZR95 calipers for track days and hill roads drive. I would also drive my 991 sometimes during weekdays and the default pads (compound 11) keep scratching my nerves; I can live with the braking noise and the dust, but the backing plate clearance of the pad with the calipers is so big that even driving over the slightest uneven road surface would shake the pad inside the calipers and make a loud rattling noise. I understand it is to prevent race pads getting stuck under thermal expansion, but it is a fuss for street drive.

So the question is: Does anyone know if there is any other pad option for the PFC ZR95 caliper, preferably street pads with less backing plate clearance with calipers (so a tighter fit and will not move freely vertically)? The caliper model is ZR95 (95.405.290.365.11/12) and PFC website shows the only option as 22mm compound 11 pads (shape 7995). I've tried searching but it looks like Endless, AP and Pagid has not offered any model for ZR95 calipers for 911.

I know people could ask why fitting a pair of 'race' calipers on a car I would drive on the street. Well it is my fun car and I would drive it on track, hills and roads for car meet. I don't mind using that pad for track, and changing to another street pad for daily would definitely be better.

Thank you in advance for information.

rcg412

FWIW - I have PFC rotors and pads, but stock calipers. To my knowledge, The noise you are hearing is from the free float rotor - not the pads (or caliper). Hope this helps.

MaxTheNomad

Thank you for your reply. I forgot to mention that I'm having the opposite combination as yours - I'm now using PFC ZR95 calipers and pads with traditional rotor+ disc (non-floating disc). This is because I accidentally bought the wider version calipers and I had to customise wider rotor to place the disc 10mm further inward so calipers won't scrath the wheels' spoke. So that rattleing noise over bumpy road could only be from the pads colliding the calipers I suppose

Thrownaway

Why did you choose PFC rotors and not another brand like Giro?

Tom@TPC Racing

I have been running the PFC ZR95/ZR96 kit with PFC 11 pads for 2 years. It has been amazing. I love it. For me, after a track weekend there's enough pad material transfer layer on the rotors to keep the brakes completely quiet for around 2 weeks of normal street driving. When it begins to lightly squeal again after weeks I do another track event and it becomes quiet again for street driving. PFC rotors are made from very hard alloy, I find pad material transfer to be effective in making this full racing brake kit quiet for street for a finite amount of time(until the normal street braking depletes the transfer layer of material). I have tried swapping different pads but didn't work for noise reduction especially because it takes times and usage to completely deplete one material layer transfer and then replace it with another material layer from a different compound. That's just my personal experience.

MaxTheNomad

I planned to use Giro or PFC rotror+disc but like I mentioned above I accidentally bought the standard version (as opposed to narrow version) of calipers and I have to customise rotors that would let disc and calipers flush 10mm inward, otherwise the spoke would rub the caliper

MaxTheNomad

Thank you for your experience Tom. Your posts are actually the main reason I made my mind to use PFC for my 991.

I suppose you are mainly referring to the squeal during the braking, which is acceptable to me. What bothers me the most is that backing plate of the pads have large clearance (workshop told me race pads are all like this, to allow thermal expansion and prevent pads getting stuck) which allows them to fluctuate and rattle when I drive over bumpy road surface. It's like having some coins in your pocket when you are jogging. This is the main reason why I want some street pads with less clearance between backing plate and calipers that would not jump up and down inside the calipers.

Another 2 questions I wonder if I can ask you about here:
1. I noticed that on TPC website you offer other compounds for PFC brake kit (08 or 64). I tried sending messages to TPC facebook to confirm but have not gotten any reply. PFC support said they haven't release any other compound except the default 11. Is it actually possible to get a pair of pad with 'street compound' i.e. 64 as mentioned on your product page?
2. According to technical spec of PFC for my ZR95 calipers (95.405.290.365.11/12) I should use pads of 22mm maximum thickness. However my workshop told me that my current 22mm pads are thin and the strokes are coming too far out. They suggest me to use thicker pad i.e. 26mm/28mm. Is this actually better, even if it is possible?

rcg412

standard OEM on 991.1 cup car. They have amazing stopping power and brake modulation on trail braking. Last a long time. But at end of day, the fact that they were OEM on a cup car speaks volumes.

Tom@TPC Racing

The pads are designed to have float for expansion and for zero drag for track performance optimization, exact same feature as on 991 Cup. Even when we raced 996 Cup and 997 Cup many years ago we removed the spring clip from the stock calipers for pad float.

The low speed rattle from pad float doesn’t bother me but I suppose my expectation/tolerance for noises are different than most having exposure to race cars and highly modded street cars all my life. Sometimes I can even time the pad float rattle to match the frequency to the PDK flywheel rattle. Haha.

Anyway, if you want to eliminate pad float noise at low speeds here’s an idea I came up with for my direct customers. The idea is to use adhesive damper plates from 993/964. Follow the images below.





993 Turbo, RS, and GT2 street cars come factory equipped with these adhesive damper plates. They hold up fine for street and track. The PFC 22mm front pads usually last 10-20 track days(depending on track layout, tire compound, and driver skill level) so for a driver who does 10 track days a year with street use between track days a set of adhesive damper plates can last 2 years or more. If you want to try this will need 12 large and 8 small adhesive damper plates.

PFC ZR95 calipers take 22mm pads. The titanium hole-vented cylinders that contacts the pad backing plate aren’t the pistons. They protrude the pistons for cooling. The piston are aluminum to match the expansion rate of the aluminum caliper body. The pistons are designed to be long enough length to safely operate in racing to the point until the thickness of the pad material becomes equal to the packing plate thickness. Which is 5mm.

Few years ago I had a car with ZR95-“R”calipers which I used 26mm pads but I had to remove the titanium hole-vented tops from the pistons, which was very difficult to remove. The thicker pads can only be used with ZR95-R calipers with the ti tops removed to create more space. This cannot be done with ZR95-S calipers.

The 64-compound pads should have been removed from our website. I have run the 64 prototype. It has less torque than the 11, which was absolutely expected. The 11 is the best compound and comes standard with the kit. I remember asking our website admin to remove the 64 from the product page, apparently he missed that task. Sorry about that. And the guys who run our FB/IG pages only post cool car pics, videos, and racing results for entertainment purposes. We do nothing technical via these social platforms. Best to contact our shop directly or your PFC dealer for tech support.

rcg412

Tom, are you saying the noise the PFC makes come from pads, not rotors? And to be clear, the sound is sort of like a bunch of empty glass bottles in a wood crate….

I always assumed Rotors… but you would know better than me,

Tom@TPC Racing

I am not there with you to hear the sound in person so I will not speculate the source of a sound. But you can stick a finger through the wheel spokes to try to push the pad radially outward and hear if the sound matches what you are hearing when in the cabin.

rcg412

I’ll try it. I always thought it was lateral (up and down) movement of the rotors in the V3 carrier…. Given its a “free-float” rotor.

Sound is annoying, but who cares on a track car.

Tom@TPC Racing

Thats what a Cup car sounds like except x5. LOL

MaxTheNomad

Ohh does TPC have any of these adhesive plates in stock? I would love to buy some if they can also be fitted to the 'holed cylinders' of ZR95 calipers! Actaully the first contact I tried was sending email to TPC mailbox but the Captcha on the website keeps preventing me to hit the send button. Would you mind PM me the email address directly?
According to your description we should be hearing the same noise lol. It should be the brake pads as my workshop said since I'm not having floating disc.

Tom@TPC Racing

The adhesive damper plates are OEM Porsche parts available from many online sources. Use the part numbers shown in the image I posted. The adhesive method is still being use in brand new cars today, the only difference is the OEM realized years ago that production cost is reduced by putting the adhesive directly on the backing plate.

I never trust those 3rd party message service apps, not even in my personal life. Sorry you don’t get through. The general shop email address and telephone number are shown in contact page for product info.