MC 968CS

Hi. I have done a couple of track days in my car now. I notice the rear calipers paint seems it be discolouring from heat much more so than the fronts. I'm running floating (AP and Brembo motorsport) rotors all around the car with cup cooling, race fluid and track pads.

I love the brakes on the GT3 and it's clear from the seat that the rear bite is massive on the car...its loves to brake hard.

I'm burning the paint off the rear callipers (as I did the fronts in my prior porsche!).

Are others who lap quickly (relative to most) finding this?
What causes it to be so much hotter in the rear?

audipwr1

You running with traction control on?

MC 968CS

Yes. In sport mode. Does TC use rear brakes, or just cut engine power. I thought it only cuts power?

audipwr1

.1 or .2 car?

TC is running rear brake at track out is my guess

You noticing accelerated rear brake wear as well?

MC 968CS

997.1

I have felt TC come in but really feels like it's the computer and engine cutting power more than brakes getting used. I haven't done enough days in it to judge pad wear yet.

Appreciate the input...let's keep that coming.

surlynkid

PASM uses the brakes. TC cuts out engine.

Fisher

There has been considerable confusion about GT3 systems. PASM on a 7.1 is not the same as PSM on a 7.2.

Speaking only of the 7.1:

The 'Sport' button on the center console is a separate system and has to do with the selection of a more sensitive computer throttle response and the opening of exhaust valves at idle and above 4K RPM.

The button to the left of the Sport button is labeled with a shock absorber symbol and controls whether you are in Normal or Sport PASM. According to official documents, Porsche Active Suspension Management (PASM) is an active damping system that offers continuous adjustment of individual damping forces based on current road conditions and driving style. If 'Sport' mode is selected, the suspension is automatically set to a harder damper rating. If the quality of the track surface falls below a certain threshold, the system immediately changes to a soft rating within the 'Sport' setup range. When the quality improves, PASM automatically returns to the harder rating.

Traction Control (TC), the button to the far right, is derived from the Carrera GT. It combines ABD, ASR and MSR functionality. Specifically configured for optimum sports performance, the benefits of Traction Control include a reduction in wheelspin under full acceleration which could otherwise destabilise the rear of the car. The standard trigger threshold is purposely so high that it is rarely exceeded during normal road driving in the dry. It is possible to raise the threshold higher still by pressing the 'Sport' button on the center console. For maximum involvement, the system can be fully disabled using the separate 'TC OFF' switch.

I hope you detected the nuances of the switch labeling and functioning. Like when the TC button is lit, TC is OFF. Also, the button labeled 'Sport' does not select the Sport PASM Mode, rather the button to its left does. In the description of TC by Porsche, where they say "pressing the 'Sport' button on the center console," I believe they mean the button marked with a shock absorber (PASM Sport) rather than the button marked 'Sport'.

In the case described by MC968, I contend that turning TC off will save his rear brakes and give him full control of oversteer.

MC 968CS

This is interesting. Thanks.

So picking up on all the systems described below, the inference is one or more or these acronyms runs the brakes. Is that correct?

Traction Control (TC), the button to the far right, is derived from the Carrera GT. It combines ABD, ASR and MSR functionality.

CosmosMpower

Turn off all aides. I think the rears may run a bit hotter though. Smaller rotor/caliper/pad and a lot of the weight is in the rear.

Spyerx

Put the .2 rear ducts and ensure you have the standard cooling ducts.
Trim the inner dust shield for max cooling flow
http://www.suncoastparts.com/product/GT3BDSL.html
turn off nannies
use caliper stickers and temp paint to validate what temps you're hitting on brakes, both rotors, pads, calipers

ngng

are the .2 bigger than the gt2 ducts?

powdrhound

I run the complete 7GT2 380/350 PCCB brake system with steel rotors on my car. For cooling I have the front large 6GT3cup brake ducts and rear .2RS ducts pictured below. The .2 ducts lowered the rear rotor temps about 40F compared to running the smaller 6GT2 ducts. I only have ABS on my car without any nannies. With this set up my rotor / caliper temps have been virtually identical front to rear, all within 10-20F running PFC 08/11. Recently I replaced the stock ABS with a PMNA 6GT3 Cup ABS. While braking performance is phenomenal now, my rear rotors are now running about 50F hotter than the fronts even after switching to 08s in the rear. Every 7GT3 I have seen smokes the rear calipers when the nannies are left on. Once you turn them off, rear brakes run much much cooler.





You have to trim the stock backing plate to fit the .2 ducts..

Spyerx

I'm not sure what gt2 have on back.

I have the ducts powderhound has with the trimmed dust guards. I also have what I think may have been stock on turbos or 997.1, the tray naca duct with the control arm scoop. I run both in rear. In fronts I have stock upper ducts and lower are cup grand am parts that attach to lower rsr link.

Anyway, my brakes run right on target temps. Never flash the red paint.

powdrhound

All the 997TT/GT2/GT3 have the naca duct tray with the thrust arm scoops. I have those also. I've seen a couple of car that had the scoops missing without people realizing it.

[url=https://flic.kr/p/p5c3WM]

Spyerx

Ok you have same setup I do.

On my car those naca ducts were missing along with the control arm scoops. Who knows why.... I added them back.