Brake upgrade C2 - GT3 6 piston caliper question

Hi all 🙂, So I recently purchased for a good price the 6 piston brake calipers P/N: 99635143230 and 99635143130, the 6 piston PCCB calipers. The rear brakes are clear as the bolt spacing will be the same. For the front the spacing is currently 130mm vs the needed 142mm which by the ways is too small of a difference to allow for spacers. So my question! What will I need to make the front work with P/N's? GT3 uprights? What else? Which rotors, thanks!

I believe you'll need: GT3 Upgrights GT3 350mm rotors and pads GT3 brake lines You'll probably need to upgrade your sway bar to a GT3 sway bar because of the drop link locations.

I hope you are sitting down when you see the price of GT3 uprights. You will need a bunch of other parts to make the GT3 uprights work, depending on how complete they are when you get them. If you are starting with just a bare upright you need: GT3 front left brake pipe 996-355-581-9B GT3 front left brake pipe support 996-355-501-06 GT3 front right brake pipe 996-355-584-9B GT3 front right brake pipe support 996-355-502-06 Brake pipe support bolts (2x) 90006711709 Caliper studs or bolts for front (4x) 85mm front GT3 front tension bolts (2x) 99634113104 Front wheel bearings (2x) 99905305405 Front wheel hubs (2x) 99134160503 Axle nut (2x) 99908463402 Left air baffle plate 99635181590 Right air baffle plate 99635181690 Pinch bolt (2x) 90037813809 Pinch bolt nut (2x) 99908444509 Speed sensor bolt (2x) 90006711709 Left Heat protection for speed sensor 99660623590 Right Heat protection for speed sensor 99660623690 Brake backing plate bolt (8x) 99921711609 Bearing retainer plate (2x) 98633166120 Bearing Retainer bolts (8x) 99921704209 As noted above you'll also need some way to mount the front sway bar drop links and the typical way to do this is with the Tarett brackets. These can only be used on threaded body coilovers. Depending on your front dampers you may need to replace them with dampers that fit the GT3 uprights. The GT3 front uprights can only be used with 996 GT3 rotors and nothing else. The 996 GT3 rotors have a 2mm offset difference from all other 350mm rotors. If you don't want to bother with this I seem to recall that someone makes a conversion bracket to mount the bigger calipers on the stock C2/Boxster front uprights.

Quotes source post: 18268489

Ha... I was waaaaaaay off. @Martin996rsr sells the C2 kit that uses a 350mm rear rotor from a 997.

The brake bias also should be addressed. The additional front brake shifts the brake bias way forward. This underuses the engine weight on the rears because the rear brakes are too small. Stopping distances can actually increase. The ultimate solution here is 997 Turbo rear calipers & rotors.

For 2500 just get yourself a Giro 2 piece rotor set and be done I just did the change and used my stock calipers the stopping power is amazing great upgrade

Quotes source post: 18268525

I am using the front 330mm c2 calipers in the back, but i have gt3 rear uprights that i think r the same as the turbo rear upright. I am also using Martins 350mm spacers, bolts and the 2014 panarama turbo rotor he recommends. They r slotted because i didnt want the drilled turbo calipers for the track. This year i bought used girodisc for the back and im very happy with them. The second piece if the puzzle is u need to upgrade the master cyl to the 997gt3 unit. If u have psm there r abs error issues to work around when u use this mc. The 3rd piece of the puzzle is the gt3 abs, it is a 4 channel system, a non gt car is a a 3 channel (rear is split). I have the entire abs from the gt3 including the abs controller. The gt3 abs is much more hands off and allows me to get to the g-edge before it interferes. The 4th piece is a good limited slip in the diff. Its really the only way to control the rear with that much brake. So with my set up i have the same propertion of brake pressure as a 997gt3 which is said to be optumum but u have 30% more brake force. This system is increduble on the track and amazes my instructors when i go deep into a corner. The final issue with the 6-gt3 front caliper is the bolt pattern is not symetrical so its said u cant fo to a 380mm rotor. U may want to seriously consider selling the callipers and getting the 997gt set up @zbomb did this on his "race" car. They r much easier to adapt but u stull ha e some of the other issues.

Yes the C2 front calipers are the same as the 996 Turbo rear calipers, and yes the GT3/Turbo/C4S rear uprights are the same, so that is a possibility. As far as I know all the PSM equipped ABS are 4-channel. I can't say about the non-PSM versions. I would be delighted to have a GT3 or a Cup ABS system. They are not cheap and rarely show up for sale anyway. The Bosch Motorsport ABS might be a better choice if going that route, as I believe it's similar in price with much greater configurability.

1. It�s not a race car 2. Going to the 7.2 GT3 380mm setup means rotors that cost $600+ each. 3. With a GT3 master and stock C2 rear setup, it seems to work pretty well. ETA. Bosch Motorsport ABS going to cost between $5-10K.

Something else to think about if you are not a gifted wrencher or fabricator, which I am not. All I want is to have my shop bolt on something that works with the least amount of fabrication and headaches. If you really want more braking, without the unforseen fabrication issues and costs, get a big brake kit new or used that is built for the 996 . ~$6k new or ~$3.5k used. FWIW, you do not need 6 pistons. All you need is a 4 piston system like my brembo gt kit. 355F and 345R. I never needed a Gt3 master cylinder either. But I bought a 996 by choice that did not have psm which may influence the need for a bigger master cylinder. The 4 piston brembo kit is more braking power than what any 200w and 100w tire can handle unless they are hot and sticky as he'll. You'll need to run hoosiers and even with hoosiers, it's more braking power than you will ever need on the track. No fade, no issues, but you gotta make sure sure you run fresh brake fluid. Yes, fresh brake fluid is a must. Keep this in the back of your mind. Most of us are not Mark Webber and we do this part time a few times a year in the summer months. It takes years to develop the braking skills and GUTs to use the braking power of the stock brakes. Many more for a big brake kit. Don't overthink it and don't over pay as a penalty. IMHO, I would use the stock brakes and first go with the Giro kit while keeping my eyes out for a used brembo, alcon, etc. Big brake kit. Why go thru the fabrication headaches and costs unless you really enjoy doing it. But again, I have zero wrenching skills. Just hate to see people spend money they don't have too.

1.5G on stock calipers, Sebro rotors and Hawk DTC60 pads... The stock system is really good with the right support parts. I think my new setup may be slightly better but it will be more evident later in the session when their better thermal mass comes into play. For 20-30 min sessions and outright braking performance, sticking with the stock calipers and not inducing any of the wonkiness that comes with frankensteining a system (like I did) makes a boat load of sense.

Quotes source posts: 18268489, 18268525, 18268684, 18268733

First of all let me thank you all for all your inputs! This really answers all for me. I will not invest into such an undertaking. I took a glance and it would be allot. Maybe an OE Brembo kit would be the best answer in the future. As for now, what I will likely do is; 1. Giro's 2. Pads (recommendations?) 3. I will have my calipers refurbished and repainted. 4. fluid 5. brake lines 6. air ducts Thank you! I agree, where in the U.S. could I look at brake kits? Curious to see a YT vid on that :-)

That is a lot of work! For what it is worth, 996 GT3 prices are still very reasonable.

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not where I live sadly. Basically 3 996s for a gt3

Vect, take a look at the sponsor list here in Rennlist. Plenty of companies that sell brake kits. Obviously, eBay for used kits that fit your 996 as well as local porsche clubs, porsche indies and thru word of mouth. Someone always has something they want to sell. I got my Brembo GT brake kit, GT3 seats and an extra set of Carerra 2 wheels this way. When they go up for sale, you buy them.

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One of the reasons I wish I lived in the US again, here it�s so much more difficult to get parts second hand. thanks!

Strong USD makes it tough as well. Girodisc system should give you what you need for awhile. Hopefully we get a weaker dollar by first half of next year.

Quotes source post: 18268539

what pads did you use?

I use pagid yellows but they r a semi-race pad and they dust a lot.

I use stock textar from fcp so they have a life time warranty and for track days I will be using pagid yellow they seem to be the best overall choice from 80% of the track people I spoke to and the other 20 recommended ferrodo