This is from a Nissan forum but it does actually contain some good info and tech from two people that are actually involved with both Brembo and AP racing. Definately more info than I have even found on here. No offence to 6speed

http://www.the370z.com/brakes-suspen...ap-racing.html

 

The Turbo suffers from a system made for comfort, not performance. I mean, it can still get the job done, but it's effectiveness and accuracy take a huge hit. Most of the problem is the vacuum related brake boosting. And while aftermarket BBK's may band-aid it, they won't fix it. I've been in a couple of Brembo GTR kitted cars and the problems are still evident. Imo unless you are willing to go remote reservoir, you are only masking the problem. The rear brakes are hardly being used at all, and you can jerry rig it to get a bit more out it or running pads with less bite in the front but that is counterproductive to me.

Porsche took the edge out of the brakes and tried to add it back with the PSM. The result is that the TT is more forgiving under brakes than say a GT3, but the engagement is slow and dull unless you stomp it.

I'd like a simple solution for the root cause to get more bias to the rear and get rid of the vacuum assisted brake booster. But there doesn't seem to be one. We have a good OEM setup from a major manufacturer. The implementation of it just isn't that great for aggressive driving.

 

Sounds like a change in pedals, MCs, and rear calipers with a GT3 cal for ABS would get you where you want to be.

 

That still won't remedy the vacuum assisted brake booster. Which is the main cause of the lame brake response. Ultimately you have to go to a standalone ABS unit and individual reservoirs which will run you about 15-20k to solve this. And you still won't stop all that much faster (unless you are riding ABS all the time). What we need is something that removes the brake booster completely and let's you modulate more. But I've tried running with the ABS off, so the brakes need some assistance, otherwise you better have some super strong legs to complete a session. Maybe a hydraulic booster of some sort.

 

If the booster response is the Achilles' heel, you can try what's on the latest-gen plug-in hybrids and EVs: a standalone vacuum pump to power the brakes.

If you're interested, PM me and I'll send you a list of parts that would work for a 996tt.

 

Have you seen this done before? I know I broke a booster pump once and because the vacuum was interrupted, the car stalled. That would have to be addressed somehow. Just wondering what work would be involved in doing so.

 

Sure. I designed this system for an EV you've heard of, and the basic setup is simple. You pull power from the ABS controller circuit and run a simple vacuum sensor/controller that turns the pump on and off at high and low vacuum limits. You'll still have engine vacuum if you want it, that just depends on plumbing.

I'm surprised that stalling a car broke a booster. It must have been an older car. Modern boosters have check valves that prevent vacuum from leaking out.

 

I certainly agree that the 996tt brakes could be better but they are by no means bad. I run RUF 6 piston front and 4 piston rear brembo calipers (probably just rebranded Porsche brakes) with 350mm floating rotors front and rear and use PFC 08 front and a more aggressive 06 rear pads along with Endless RF 650 fluid. I also have 996 GT3 CUP car brake ducts on the front along with GT2 front fender liners, and GT2 brake ducts in the rear. I've never had any complaints with braking performance at the track. After a hard 20-25 min session, my brake rotor and caliper temps run within 10-15F degrees on all 4 corners which to me would indicate a pretty good balance. I have found that braking technique has a lot to do with brake performance as I brake fairly late but very hard just above the threshold of the ABS cycling. Everyone that has ridden with with me was surprised at the power of the brakes. I DO NOT have PSM which might help.

As a point of reference, my buddy who's a very good driver tracks his 2008 GT3 with 380/350mm rotors and he goes through rear pads much faster than the front indicating a much greater rear bias. His rear temps run about 100F hotter than the fronts, enough to turn his rear yellow calipers brown. I'm not sure this is an ideal set up either. I've run with him and he doesn't out brake me by any means even though he's about 130lbs lighter.

 

I agree^ I have a GTR Brembo kit on the front of the my Z06 ST1 car but never got the braking feel or bias right till I got a Doug Rippie racing master that allowed adjustment. The turbo needs something similar for sure to push it hard on the track.