changster123

Before I shell out money for 996 GT3RS front and rear uprights, I want to make sure OEM 350mm brakes are good enough? I think if I wanted to install the bigger 380mm brakes from a 997 I would have to buy the 997.1 GT3RS uprights instead of the 996 GT3RS.

Bigger rotors are always better for free brake torque but not necessarily needed.

Do most people here keep the 6 GT3 OEM brakes stock besides maybe different rings like AP J Hooks? What about the 997 master cylinder to push more fluid but keep same bias? Keep the OEM 6GT3 brake lines?

I do find it funny Essex has a rear big brake kit but no front kit. Is something wrong with the rear in our cars but the fronts are fine?

Thanks!

spiller

These cars are under biased in the rear. It is thought the 350mm rotor assists with this but some take it further by fitting more aggressive rear pads. I have had that set up on one car and then factory sizes on various other cars. I wouldn’t bother with any of the upgrades. Even 2 piece rotors are overkill for most cars out there. Fit some good pads, non drilled rotors, make sure your brake lines are supple (OEM replacements are well up to the task), replace the fluid with Castrol SRF and you’re done.

I have been running DBA 4000 rotors on my cup with Ferodo DS1.11 pads and have been very happy. The DBA are cheap at around $550 AUD front and $600 rear per pair. They have so far lasted very well. The oem drilled style rotors crack prematurely. Some others on here are running Centric branded slotted rotors for around $150 USD with good results on track. I have gone the expensive Brembo 2 piece in the past at 3K a pair and I just don’t see the value in that, beyond them looking cool. The Ferodo pads whilst very good are not as good as PFC but they were substantially cheaper. Plenty of stopping power and ability to work under high temp, but not as good initial bite as PFC08. The Ferodo have gone up in cost about 50% in the last year by my calculation so I probably won’t run them again. I may go back to PFC or try Project Mu Club Racer.

YMMV

changster123

Fantastic. Thanks for the feedback! Great to know it's an area I don't need to spend big $$.

De Jeeper

My car runs 2.12s at watkins with zero brake issues. I dont think thats bad for 3400lbs with 350f and 350r rotors. Rears r just a spacer for the caliper. Zimmerman and sebro rotors, with pagid r29s. I use front c2 996 calipers in the back to even out the bias.

Also 380s will likely need 19" rims if using non race track wheels.

changster123

Fantastic, good to know. Sounds like 350 is fine.

What is the difference between the c2 996 front calipers vs the 6GT3 rear calipers? Bigger piston sizes? If yes, by roughly what % if anyone knows? I'm curious how much more rear bias people tend to want in this car.

De Jeeper

Yes the pistons r bigger. I also use a.997 gt3 mc. The bore is bigger and gives a firmer pedal.

Gt3 rears r 28 and 30mm

C2 fronts r 36 and 40mm

The c2 calipers r the same but they dont have the mounting boss to secure the soft line but the lines r fine floating.

changster123

Ok awesome.

The 997 MC is from which model of 997? Or are they all the same? And only the MC needs replacing and none of the auxiliary parts (lines, etc)?

EDIT: Nevermind I found it. You just need a brake line from an old Boxster. Part number 996 355 313 04. I also see you said 997 GT3 MC.

changster123

BTW that's quite a big change in piston sizes (about 30%) which equate I believe to almost double the total piston area (my math is fuzzy though). The 996 GT3 needs this much more rear bias eh? Does it provide much better balance in braking in most conditions and not lock up the rear?

De Jeeper

When i did the math it made the front rear bias slightly more then the 997-3 with about 30% more piston. Thats why i went with the bigger master. Track guys really like the 997-3 bias so i just kept it.. Its probably a little strong in the back but for street driving u would never know. On the track i played with using pagid 19's in the back and liked them because they have a little less initial bite but the 29s dont really bother me.

In addition i get about 20-22 track days out if the rear pads and 23-25 out if the fronts so i wouid say they r well matched.

changster123

Nice one. Do the C2 calipers bolt right up?

changster123

Our shop has these rear calipers lying around from a 997 Turbo or GT3. The bore size is 34/34 though.

De Jeeper

Yes but as i said they dont have the threaded boss for the soft line bracket.

I use these rotors from fcp and simple caliper spacers to get room for the 350 rotor.

ZIM-460158720
ZIM-460158620

Do the math as the 34/34 might be a good match for the 6-3 fronts?

rodneyr

I personally don't think you need to update the brakes. The important thing is to update the cooling to the rotors, e.g. the GT2 brake ducts. This is a one-time cost and will improve the life of rotors and pads. Of course, make sure you have good brake pads. I use pagid RS29's and have Deman front slotted rotors which last a very long time.

cgfen

"I want to make sure OEM 350mm brakes are good enough?"
good enough for what purpose?
Cup racing probably not
Everything else probably yes.
you seem to like to perform modifications, if it makes you happy have at it. It is your time and money.

changster123

Actually I just love to drive. I'm doing hard driving 2-4x a week right now through the mountains and coast, and 2-4x a month on track. When I say hard driving on the street it is definitely impossible to do in the US as you would be thrown in jail. My tire pressures rise from 26psi to 36psi FYI on the street.

I really want to get this car up to my spec/liking because it's hard for me to want to take this car out instead of the others that have coilovers/kinematics/brakes all done. To be fair it's only because this car is 20 year old on OEM suspension/chassis. The engine sound is phenomenal and the feedback is awesome, but currently lacks other parts of the equation. This is why I'm asking about the brakes now.