We've test fitted the 997T rear brakes on a 9974S (same brakes as 996T). Stay tuned for a matching rear setup to our GT3 front brake kit!

 

For the record, I finally completed the first stage of my brake upgrade.

I have a 2001 996TT and, like many others, had overwhelmed my stock braking setup at a trackday recently. After looking at all of my options and taking many factors into account, I wound up going with a full 997TT brake upgrade.

I successfully bolted on the front and rear calipers (front 6 piston-same as 997 AND 996 GT3, rears 4 piston with back cross brace), pads and rotors (350mm front and rear). I did purchase and install the 997TT caliper bolts as they are a bit longer than the stock 996TT caliper bolts. The fronts were a few mm short and likely could have been retained but the rears were too short for safe usage according to my installer (although (I drove around for a few days while the 997 bolts were on order).

I also took the opportunity to upgrade to SS lines (Agency Power) and I used Motul RBF600 for a full system flush and upgrade.

My next steps will be to upgrade the front rotor either to a Coleman solution or possibly the Protosport option when it hits the market (they are doing one piece, factory-like, cryo treated rotors that are SLOTTED and not cross drilled). They've done these successfully for the 997GT3 and many users have found them to last 2-3X as long as the stockers under harder track usage. I will also likely move to a more aggressive pad compound for tracday usage but like the stock 997TT pads for normal street usage (little to no squeal so far). So far the brakes feel like stock with slightly longer pedal throw given the front 6 pistons. Feel is similar to my previous setup and still stops the car amazingly (looks great too!!!!). I have not had the car to the track yet but will report back on my findings. I anticipate this setup to suffer less from fade and it will hopefully stand up to repeated lapping much better due to all of the uprated components.

Hope that helps everybody! This is a viable upgrade for all 996TT users and cost me about as much as a front Brembo upgrade (purchased slightly used and installed!)... Watch for them used as the 997TT and GT3 guys upgrade!

Note that the 997 TT and GT3 evidently use the same calipers and rear rotors. The front rotor on the GT3 has a different offset and will not directly bolt on to a 996TT. If you purchase a 997GT3 brake kit, you'll have to get a 997TT front rotor to work. I also believe that the 997GT3 pads may be a more aggressive compound (Pagid RS-29?)...

 

Well done Kato, glad things finally worked out for you...well worth the upgrade.

 

Regarding my post (3 up from here), we have finally released the OEM 350mm rear brake upgrade for the 996/7 widebodies (and 997 C2S). Check out the thread I made in the Vendor Classifieds section or go see it on our website (link below). Let me know if you have any questions!


Porsche 350 MM Brake Kit - Rear - $1625.00

 

A warning to those who have or are considering putting 997TT brakes on a 996TT or GT3. Just because parts physically bolt up and are larger, does not mean that they are appropriate.

You may not be aware of the factors that contribute to proper front/rear brake balance, and the dangers that accompany improper balance.

The rear brakes on the 997TT are vastly different in terms of piston area compared to what the 996TT was designed around. Installing the 997TT brakes on the 996TT results in a 48% increase in the power of the rear brakes relative to the front. The 997TT's system (i.e. master cylinder, booster, proportioning, and ABS system) are designed around these parameters, the 996TT's coresponding components are not.

This results in an unstable brake system that will lock the rears long before the front. This is highly dangerous. At the very least the ABS system will be brought into play prematurely to counteract the rear lockup. This will decrease the brake system performance.

 

I have front Brembo 380 mm rotors and 8 piston brakes (Gt kit) and I installed rear 350 mm 997TT complete brakes, raced the car several times and it brakes perfectly I do get a strange feeling when reaching the end of a long straight and I step on the brakes like if the car doesnt throw the nose down but up for a second and then I step on them more and it brakes perfectly, nothing serious I brakes like nothing I have used before, GREAT!!!!! If that milisecond is the feeling you suggest I dont mind I feel it is a good trade off... nothing serious at all

 

The balance problem is actually not present with the 8-piston front system that you have (which has been discontinued for several years now). Though I feel that this combination would result in an unacceptably long pedal.

With any of the currently available front upgrade systems, or retrofitted OEM 997TT front brakes the balance of the system is severely compromised and could be unsafe.

 

How did you come up with 42 percent? can you give us some #'s?
How is the bias for a 996GT3 caliper with the stock 996turbo rear setup?

 

48%

996TT:
28/30mm pistons, 330mm discs, effective radius 136mm

997TT:
34/34mm pistons, 350mm discs, effective radius 147mm

Brake torque = (Piston Area) x (Effective Radius) x (Friction Coefficient)

Friction coefficient can be treated as the same between the 2 systems.

Changing to 996 GT3 calipers or 997TT calipers on 350mm discs has a negligable effect on the front/rear brake balance.

 

By the long pedal you mean the pedal feel right??? Cause the car stops perfectly and brakes perfectly , the sweet spot for hard braking is as you mention a little deeper or deeper than normal.....

 

Yes, I just mean that the pedal travel with the system you're running would have a longer pedal stroke.

 

You are right, Mark, and I highly doubt anyone would purchase this rear brake setup without simultaneously buying, or already having the front brake upgrade to at least the 6-piston GT3 setup (which would be a very balanced, optimal setup all around for the car).

Not to say the Gran Turismo kits haven't been very popular for us!

 

With any of the currently available front upgrade systems, or retrofitted OEM 997TT front brakes the balance of the system is severely compromised and could be unsafe.[/quote]





Your currently available front upgrade system (6-piston monobloc) has been running on my 996tt for severral months and has given no unsafe braking situations. The main problem was the rear brakes were no longer doing enough work and I was going through front pads rather quickly.

I put 997 rotors on the rear using my 996 calipers with Pagid Blacks and it really helped the F/R balance a lot. I did 3 track days with this setup and still had plenty of front pad left whereas before, the fronts would have been completely used up in less than 3 days.

I have just purchased and installed your rear GT kit with the 350mm rotors but haven't driven the car yet. Shouldn't the balance improve even more with this setup?

 

You haven't read all my posts. As I have stated, the issue is present with any of the currently available Brembo GT upgrades on the front or with retrofitted GT3 and 997TT setups. Those are nearly identical in terms of front brake torque compared to the stock 996TT system (as it should be).

 

The Brembo GT brake upgrades maintain the OEM brake balance whether installing a front-only system or installing a front and rear system. The brake upgrades are primarily for fade resistance (with other benefits such as floating discs, weight savings, etc.) and are designed to maintain the same brake torque as the stock systems. This is for proper balance and ABS system performance.