I had all 4 corners replaced with 997TT calipers and disks.

The 997TT comes with 6 pot calipers similar to the GT3 upgrade part.

So far the only difference is a slightly mushier brake pedal, which I assume is due to more brake fluid flow dictated by more brake pistons. I'm sure these things are much better heatsinks simply due to the bigger size. 18" stock wheels still fit as well.

Anyone know if the GT3 or 997TT come with a bigger piston in the master cylinder? That would stiffen the pedal back up.

 

I was told that the fluid volume in the stock 4 piston 996TT calipers equaled the volume of the 6 piston GT3 brakes owning to the fact of the varying piston sizes between the two. 997 brakes may have different volume. When I upgraded to the GT3 brakes I had no change in the brake pedal feel from stock.

 

I also did the rears. Maybe that's the difference?

 

Rears have bigger pistons...but just that shouldn't cause mushy pedal.

 

ARI, The bore size of the mastercylinder on the 997 is different than that of the 996. I blieve the Brembo rep pointed that out in my Fact and Fiction Brake thread that used to be a sticky. You might be able to just upgrade to the 997 mastercylinder, but there may be other issues with the ABS as well. I'd do some research before driving that car to hard with that current setup.

Mike

 

Will do. So far so good though.

I'm carefully looking for any signs of too much rear brake bias and any negative effect on handling. So far I have seen none.

Could be the system has some air (not likely, but possible). The difference isn't dramatic. So far It's definitely an upgrade I recommend for the price.

 

I also did the rear brakes at the same time.

I forgot that when I first drove my car after the upgrade I did have the pedal go closer to the floor. My tech re-bled the system and that corrected the problem.

 

Please keep us updated...

 

had the same issue with my 996 TT, after i installed 997 TT complete fronts.

 

can you elaborate? What issues? Were they resolved?

 

Revived! Any updates?

 

We have actually created a complete vehicle kit that includes oversized brake rotors and calipers, performance brake pads, and ECS Exact-fit stainless steel reinforced brake lines, for front and rear axles. For more information Click Here

 

It's no secret that when you go to the larger 997TT/GT3/2 rear calipers you will end up with a softer brake pedal than stock as you are having to more more fluid with the larger pistons. The stock front 4 pot calipers 996tt and a 996GT3 6 pot calipers have virtually identical piston volume so pedal feel will not change if you just swap out the fronts. It's a different story when you change the rears as the 997TT/GT3/2 rears have almost 50% greater piston area than the 996tt rears. You will end up with a softer mushier pedal after the change. No way around it, it's simple math...

FYI, the 997TT PCCB 6 pot calipers designed for the 380 rotors have a 5% smaller piston volume than the 996GT3 calipers and the 997GT3/2 PCCB front 6 pots again have about 10% smaller piston volume than the 997TT PCCB calipers, or 15% less than the 996GT3/2 calipers or 996TT 4 pots. Still with me? Lol! In addition the 997tt/GT3 brake master has a 12% larger piston area than the 996tt brake master. That is why the 997 GT3 cars have such a firm brick like brake pedal.

I run the 2011 GT3 RS PCCB 380/350 brakes including the 997 GT3 brake master on my 996 Rturbo. The brakes feel identical to my friend's 997GT3 that has the same brakes. We both use steel floating rotors instead of the PCCB discs. It feels like you are stepping on a brick. It's a huge difference compared to the stock set up or even the 996GT3 350mm set up I had previously which felt mushy in comparison. Drive a 996TT and a 997GT3 with the PCCBs back to back and you will see what a huge difference it is.

The 997 brake master should be a part of the conversion to the larger rear 997tt calipers if you want a firm brake pedal. The difference is very noticeable. It's a simple swap as you can see in this thread...

https://www.6speedonline.com/forums/...tion-27mm.html




997.2 PCCB w steel 380mm rotors on 996TT by pwdrhound1, on Flickr


997 GT3 brake master on 996TT by pwdrhound1, on Flickr

 

Awesome - thank you. I am running GT3 front brakes (suncoast kit) and stock rear brakes on my 996TT and want a bit stiffer pedal.

 

FYI: I just ordered a set of 997 turbo rear calipers because of front brake bias with my Stoptech 6 piston 380mm BBK and will be changing my brake master cylinder to compensate for the larger calipers. I also bought a custom brake line for the conversion from Pwdrhound to make the DIY modification as "plug-n-play" as possible. I was able to find the 997 GT3/997 Turbo brake master cylinder (OEM part number 99735591030 manufactured by TRW) on Ebay for $256.76 with free shipping. I also found the part at Koperformance.com for $265.27 and Importecautoparts.com for $265.08.

I am not affiliated with any of these websites and am just posting this information in case anyone else is thinking of doing this modification to their brake system.