Scott.

Long story short, my 996TT will eventually be a track **** since I only use it for errands and road trips:

- 997 GT3 master cylinder
- Custom 997 GT3 cylinder line (thanks powdrhound!)
- GT3 front calipers
- Brembo 350mm floating rotors - front (thanks vivid)
- Carbotech XP8 pre-bed pads (works amazing in our chumpcars)
- Stainless brake lines
- GT3 brake ducts (will switch out to cup or GT2 ducts)
- Castrol SRF fluid

I'm tempted to get some cheapy 350mm slotted rears instead of the brembos but still on the fence. Thoughts?

PAULUNM

Why are you doing the 997 GT3 master cylinder?

powdrhound

That should be a nice improvement Scawt. Hope the brake line you got from me works out for you. You're going to like the 997GT3 brake master! You will definitely need to upgrade your
rear rotors to 350 from the stock 330s otherwise your brake bias will be out of balance as the rears will be underutilized and your braking will suffer. Even with the 350/350 set up you will
want to run a more aggressive pad in the rear as the rear calipers are fairly small on the 996 cars. PFC08/01 is popular as well as Pagid 29/14.

I used to run the 6pot 350/350 system with floating steel rotors and just upgraded to the 997.2 PCCB 380/350 system with slotted floating steel rotors. Cost was not much more than the
350/350 system but the performance difference is huge. If you are going to be seriously tracking the car, it might be something to consider before instaling the 996 six pots. Here is a write
up I did on 6bling the other day for someone going down the 380mm/350mm route:

I ended up having my 996TT based car converted to 380mm front and 350mm rear steel floating rotors but the only way to do this is to use the 997.2 PCCB calipers (225mm bolt spacing)
that are used on the 997TT with PCCB or the 997GT2/3 with PCCB. These are designed for use with 380mm front and 350mm rear rotors. The front 997TT or 997GT3 PCCB calipers are
visually the same but the piston area is about 10% smaller on the GT3 calipers which will give you a touch more rear bias and a slightly harder pedal. I have both the GT3 and TT versions
but have not compared one to the other yet. When you do this conversion, you will need to upgrade the brake master to the 997GT3 27mm version to firm up the brake pedal as you will be
pushing more fluid due to the larger 34mmx2 rear piston calipers. It goes without saying that you will need to upgrade the rear calipers to the larger 997TT/GT3 units with 350 rotors otherwise
your brake bias would be totally wrong.

I tested this brake set up at the track last weekend and it is phenomenal as far as heat dissipation goes. The greater rear bias from the larger rear calipers works extremely well and with the
larger 997GT3 master your brake pedal is rock hard. I use PFC 08 pads and Endless RF650 fluid and this set up feel exactly like the 380/350 PCCB set up on my friends 997GT3 RS and in my
opinion is far superior to the 996 GT3 six pot 350/350 set up that I ran before. On the surface, it does not necessarily brake any better than the 996GT3 350mm set up, or the stock TT 4 pot
330mm set up for that matter, but it does provide HUGELY better thermal dissipation when you hammer the car at the track for extended periods and it does shift the brake bias to the rear which
does help braking performance a bit compared to the 996 system. I do have all the GT3 cup cooling ducts on my car which further helps with cooling. The one thing you will need to be careful
of is the selection of wheels if you run the 380mm set up as only a hand full of 18" wheels will clear those brakes. My track 18x9 front wheel will clear the 380 calipers with about 3/16" to spare
but they are manufactured to work with the 380 set up. The silver 5 spoke wheels are 19x9/12 and the grey track wheels are 18x9/12 in the pics below. Hope that helps.

powdrhound

The 997GT3 master moves about 20% more fluid than the stock 996TT master and as a result really firms up the brake pedal compared to stock. It is basically a must if you end up running the larger 997TT/GT3 rear calipers because they have 40% larger piston area compared to stock... Go drive a 997GT3 back to back with a 996tt and you will see how much softer the brake pedal is on our cars in comparison. The 997GT3 master when combined with SRF or Endless 650 will give you a rock hard pedal.

JG 996T

Looks good, nice laundry list for when I get around to installing my "new" 6 pots. (also from pwdrhound).

If you can find a set of "cheapy" slotted rear rotors - let me know - I couldn't find any slotted rears. The oem drilled are pretty reasonably priced.

jbossolo

^ Girodiscs? Not exactly "cheapy", but well-made.

PAULUNM

Interesting, thanks. I assume not necessary with 996 GT3 calipers with a 996 turbo master cyl?

powdrhound

Not necessary but would be a huge improvement. The relatively "softer" pedal of the 996GT3 system compared to the 997GT3 system was one of the main complaints I had prior to changing brake set ups.

powdrhound

A set of Giro 350 slotted rears is about $1200 all in. Very good product and about 5lbs lighter per rotor than the OEM drilled 350mm rotor. Well worth it in my opinion..

jbossolo

^ Agree 100%.

32krazy!

a tip for the brake swap guys! i just did a rotor pad line maintenance swap. what i found was a strange setup regarding the lines. from the fenderwell mount is a flex line going to a braket and then a hard line to the caliper. the flex only has a flat spot on 2 sides to apply a wrench and a very small brass type of fitting on the hard line. these are very diffucult to get to and will stripp easily!! (dont ask me how i know!) according to my dealer there are only 3 drivers side hard lines in the usa. (2 now!) use high quality brake wrenches and be careful!

PAULUNM

Just to confirm- no issues running 996 GT3 calipers with a 997 master cylinder? Wouldn't the 997 part change the bias toward the rear, which wouldn't work with the 996 rear calipers?

What does a 997 GT3 MC run these days? You have me thinking...

powdrhound

No issues whatsoever. The OEM MC has a 25.4/25.4mm piston versus 27.0/27.0mm for the 997GT3 MC so the balance is unaffected. You are just moving more fluid... Porsche changed the brake bias on the 997 cars by using rear calipers with 40% greater piston area compared to the 996. The 996TT/GT cars really need more rear brake bias and that is what Porsche rectified with the 997TT/GT cars by going to larger rear calipers thus necessitating a larger MC. The 997GT3 MC can be had for under $300. At the dealer it's about $500.[/QUOTE]

Scott.

Yeah, the master cylinder is cheap if you don't get it from the dealer. The OEM manufacturer is TRW and the part # is 997-355-910-30. I paid ~$265 shipped from KO but other online places have it for similar prices.

rb4u

How about 380mm rear rotor BBK upgrade Is it available?