AutoQuest Motorsports

For your reference, we could have made a cheap set of stainless steel pucks. However, stainless steel pucks or a stainless steel piston pressing against the pads defeats the entire purpose of having the pucks there in the first place...to be a thermal barrier preventing heat transfer into the brake fluid. This is why we went with Titanium to offer similar thermal barrier properties as the ceramic but without the risk of them breaking.

Unfortunately the design of the puck and piston in the caliper doesn't allow for anything to grip onto. The pistons are recessed in the caliper and can't be removed far enough to grip onto them securely with something that wouldn't damage the piston. We feel like it is not possible to accomplish. HOWEVER...if you figure out a way to do it more efficiently than removing the pistons, without potentially damaging any of the components, you'll have a box show up on your doorstep with a "Kudos" note and some kind of handmade trophy made out of car parts haha.

Mech33

It's nothing too crazy... I'm imagining something like this (with the "fingers" end slightly smaller than the puck surface), but in a configuration similar to a caliper spreader where it pushes against the puck surface on each opposite side of the caliper and spreads just those pistons apart:



As you spread the tool, the pistons will go into the caliper until they bottom out internally against the caliper structure (I assume), and at that point you will be essentially clamping the pistons down against the caliper cavity internals themselves.

I assume that should be plenty of friction force to let you then get in and put an allen key through that center hole in the tool and loosen / remove the screw. If you make the tool symmetric, you could even loosen the screw on the pucks on both sides of the caliper at the same time. Then repeat 2 times to complete for each of the 3 pairs of pucks.

Mech33

Or if you want to be really MacGyver, just use one of these with a hole drilled through one of the sides (so that you can insert the allen key), and use a couple of thick washers between the puck and the tool so that you only put the spreading force against the puck surface and not the rest of the caliper / dust boot.

Mech33

Or here is something that would probably work with no mods whatsoever (just have it press against the puck directly adjacent to the screw head so you can still unscrew it, while it presses down against the puck to hold it in place against the caliper internals):

malmasri

I have had my calipers replaced under warranty last year just before Porsche decided to change its approach and deny that claim, they did not last very long before they cracked again....I decided to use the Ti option and have done many events without an issue....a costly option but worth it if you track the car .

Petevb

Correct me if I'm wrong, but aren't the OEM Porsche pucks Zirconia based ceramics? And don't they have less than half of the thermal conductivity of even the better Titanium alloys (transferring less than half the thermal energy to the brake fluid, which is why Porsche used it in the first place)?

It seems there's a performance vs longevity trade-off here that's being overlooked. Or do you feel that's not the case?

Dr.Bill

Inconel might work - is it harder to machine than titanium? (I'm assuming these pucks are 6Al4V Ti)

991carreradriver

One of the considerations is thermal conductivity of Titanium Alloy versus the stainless steel replacement pistons by a competitor versus the OEM ceramics.

I am not a scientist, but a little basic research seems to indicate that titanium alloy transfers less heat than stainless or ceramic. The impact of reduced heat transfer is somewhat confusing to me. Does this mean that pads and rotors will retain more heat?. Or does it mean that moving air will have a more advantageous effect on the heat dissipation as it will not move to the fluid as quickly?

Any thoughts by the experts?

Spyerx

it keeps the heat in the pad, and out of the caliper/fluid.

The reason these pucks are cracking is whatever pads are being used are dumping all the heat into the caliper.

Those with cracking pucks, what pads are you using?

991carreradriver

That is my thinking. Now with even less heat transfer to the caliper and fluid, the heat has to go somewhere. So it will stay in the pad and transfer to the rotor at a greater rate. So are we now simply moving on from one problem (pucks) to warping of slotted rotors or greater cracking rate of of cross drilled rotors.

TRAKCAR

Getting my pucks checked out as I write this.

TRAKCAR

My shop just now:

So there we go!
Strange that I need 2 for the barely used rear and 1 for the on fire usually front..

Petevb

Heat transfer is a function of thermal conductivity- the higher the value the more heat transferred. The number depends on the alloy or type of ceramic and the operating temperature. Some typical values for comparison (W/m*K):

Pure Titanium- 21
316 Stainless alloy- 16
Inconel 718 (high temperature aerospace stainless alloy)- 11
Ti6Al4V (high strength aerospace grade Titanium alloy)- 7
Zerconia (high temperature, high toughness ceramic)- 3

Heat transferred through these materials will be proportional to the thermal conductivity, so if the stock pistons are Zerconia as I believe then heat into the caliper and brake fluid would be 2.3x greater with that particular Ti alloy, 3.7x greater with Inconel or 5.3x greater with the cooking grade Stainless. In reality it's more complex- the geometries and cross sections of the parts will be different, etc, however it gives a pretty good idea. Thus the data suggests to me that while Ti pistons will be a marginal improvement over stainless, from a thermal point of view they seem at least as great a detriment vs the OEM pistons.

SmokinGTS

It may be that the pads are being used right to the end and transfer the heat more efficiently. It may not be the pads you are using as much as how far you wear them down.

Mech33

Easy enough to characterize the stock puck vs the Ti puck to determine the relative thermal conductivity between the two.

It would be nice to see vendors gather quantitative data like this.