TT Brakes on a 1999 c2

I am thinking about putting TT brakes on my 1999 996. LA Porsche sells the calipers and rotors but not the hubs/carriers etc. Does anyone have a parts list and part

Ah. I was waiting for someone to ask this. OK, I need to know what has to be changed to use the TT or GT2/3 calipers on my C2 (is Salazar's car a 2 or 4?). I assume that this is much easier to accomplish on a C4 (since the abovementioned cars use the C4 chassis) and I understand (or assume) that the Hub Carrier must be swapped out for one that can hold the TT or GT2/3 caliper in the right spot (or perhaps not?) but if in fact the hub carrier does have to get swapped for the TT GT2/3 hub carrier, how will that work with a C2 front suspension? I hope the answer is not that I must then use C4, TT, GT3/2 front shocks and springs. Sorry for not answering your post Salazar but maybe we can both learn something from this.

My car is a C2. To answer one of your questions, the front hub/carrier has to be replaced. I hope that somebody has an answer for the rest of your questions.

If we know that the hub carrier must be changed, I think that it's safe to assume that we would have to use the TT, GT2/3 hub which was designed to work in a C4 chassis. If that is the case then I will not be able to use C2 front shocks and springs and that will be an issue for me. Anyone?

The hub carrier and wheel bearings must be changed, plus a couple of other minor parts that I'll look up when I get home. This will work on a C2, not sure about a C4 but I assume it will as well. You don't need to change any other suspensions components like springs or shocks to do this swap. I've heard the easier swap is to install the big red brakes from the Boxster S, which is supposed to be a straight bolt-on for the C2. I went the GT3 conversion route because the Boxster S wasn't out when I did mine, so I don't have any first hand knowledge of this but I've seen a couple of posts on this board, indicating that it does work. Karl

Firstly, if the hub carrier must be swapped out for the TT one, it should be very easy on a C4 because the TT is based on that chassis. It's the C2 that would be harder because the TT hub carrier (assuming that it uses the same suspension as the C4) uses different shocks and springs versus the C2. The Boxster S has the same exact calipers as the C2 or c4 except that the Boxtser S' are red, the C2 are black and the C4 are silver. So you have a C2 with GT3 brakes? When you say GT3, do you mean 1999 GT3 or 2004 GT3 with the six piston?

Karl S, The Boxster "Red" brakes are the same size as the standard C2/C4... just red. I agree the better brake setup with hubs is the GT3 brakes. I think you must also use 5 mm spacers on the front to clear the calipers with most 18" wheels.

I was just about to say the same thing Loren, but you beat me to it!

Karl: I see you are from DC. I live in Chevy Chase. If you can find the part numbers or any other info. it would be greatly appreciated. Would like to confirm that the only parts I need to order are the hubs and bearings. The BIG reds and calipers are sitting in my garage but i dont want to start the project over a weekend and then (on Sunday afternoon) find out that I dont have all the parts. Salazar.

" I agree the better brake setup with hubs is the GT3 brakes. I think you must also use 5 mm spacers on the front to clear the calipers with most 18" wheels." yes, you do need the GT3 calipers and no i didn't need spacers on my carrera 5 spoke wheels. that said, anyone interested in buying my 4k mile old GT3/TT brake kit WITH wheel carriers, rotors, pads, etc? i'm thinking about getting some more serious brakes even.

OK, here's the scoop from PET. The GT3 and GT2 use the same parts. The TT uses all the same parts except for the wheel carriers, which are different. Here's what you need to convert a C2 to GT3 or GT2 (non PCCB) brakes: L wheel carrier - 996 341 157 91 (1) R wheel carrier - 996 341 158 91 (1) wheel bearing - 999 053 042 07 (2) tension bolt - 996 341 131 90 (2) bearing cover - 986 331 661 20 (2) wheel hub - 986 331 605 20 (2) 5mm spacer - 996 361 605 90 (2) The spacer is optional depending on what wheels you are running but it is required for the Sport Design wheels which were standard on the GT3. It is not required for the GT2 or TT wheels. Can't comment on any others. The TT uses different wheel carriers for AWD, so I suspect the same would be needed to covert a C4 to use the TT calipers. The TT wheel carriers are: L - 996 341 165 05 R - 996 341 166 05 all the other parts listed for the GT3 are the same and all are needed to do the conversion. If you have a set of TT calipers and rotors, check the part numbers. The standard TT calipers and rotors are the same as the GT3 and therefore should work fine with the GT3 wheel carriers listed above. The standard TT calipers are: L - 996 351 429 10 R - 996 351 430 10 These of course, will also work with the TT wheel carriers which is what you'll need if you're converting a C4. Hope this helps, let me know if there are any more questions. Karl

Will the above list allow you to put stock TT calipers on a C2 without changing the rotors, or do the rotors need to changed to TT rotors as well? Does this modification affect the ABS or PSM system in any way which would require a modification of any sort to them?

You need to change to TT (13") rotors with those calipers and wheel carriers. My (C2) PSM and ABS have not been affected by the upgrade to TT/GT3 13" front and rears.

Check with a board member "Ruey" I know he has done this mod. I sold him my turbo carriers and brakes.

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I'm digging this thread up from the past Does the master cylinder need to be upgraded for the GT3 brake swap?

Karl, did you do front and rear, or just front? If you are doing the rear, do they just bolt up or do you need the aforementioned parts for the rear too?

BTDT, got pictures. Will post some comments later.

OK. First what I've found out playing with these brakes, intially with my 951 and later with this C2. FRONT 1. Hubs ( in this context hub means both wheel carrier and actual hub ) match with discs, caliper offsets are the same. Ie. if you use hubs from a turbo, you must use discs from a turbo. Independent of disc diameter or origin of caliper. However if you have hubs from a GT3 or GT2 ( which is actually a GT3 hub ), you can use turbo's disc with a 1.5mm shim between the disc and the hub. So for a C2 use GT3/2 hubs with GT3/2 discs. Or 996 / 997 turbo disc with those 1.5mm shims. Calipers may be either from a GT3 mk I or II, GT2, 996 turbo or 997 turbo. For a C4 use turbo's hubs, discs either from 996 turbo or 997 turbo. Calipers per your preferred colour... 2. Suspension. GT3/2 wheel carriers match with C2's struts. Turbo's ones with C4's. 3. Wheels. Anything with offset more than 45 mm interfere with 6 piston calipers. 18" is a must. If you use 4 piston calipers with 330 mm disc, you may do with 17" wheels, but not with all of them... GT3 mk I disc and 996 turbo disc = 330 mm GT3 mk 2 disc, GT2 disc and 997 turbo disc = 350 mm REAR All 330 mm discs mix with all calipers meant for a disc of the diameter. No need to change hubs/wheel carriers. My own set is a mix of GT2 wheel carriers, 997 turbo front discs and 6 piston calipers ( and those 1.5 mm shims ) at front. Rears are from a 996 turbo. 5 mm OEM spacers at front. When buying an used set of front wheel carriers, be sure that they come complete. And change bearings before assembling them. I've did last summer about 150 2-mile laps with that set without problems and the mastercylinder, brake booster and ABS unit are original C2 parts.

Great post! Thanks for all the info.

I looked into this several years ago, bought F&R TT calipers, hub carriers, hubs and all hardware to do the conversion. I then started researching a bit more and used my knowledge from setting up roadracing motorcycle chassis, suspension, and brake systems. I make my living working on them, BTW. Anyway a couple of critical points: The TT and GT3 calipers have larger pistons than the C2 or C4 and can displace a lot more fluid as the pads wear down. The TT and GT3 master cylinder pistons are larger as well to yield a pre determined effort vs. travel @ pedal ratio. The Fluid reservoirs are much larger as well on the TT and GT3 larger yet. Under the right conditions braking failure could occur if the pads wore sustantially and the reservoir became delpeated of fluid. If you must fit the larger calipers, fit the approiate master cylinder and reservoir as well. The real reason and most important one for not fitting these brakes is the fact of adding more unsprung mass to the lighter duty C2 front suspension didn't make any sence. If the cars power was not greatly increased, to add a lot of unsprung weight to the suspension seemed like I was going backward performance wise. The stock calipers are great for a stock or lightly tweeked motor. Learn to drive better and go pads with a higher CofF. I agree the Big Reds look pretty awsome, but after some thought, I concluded maybe they look awsome, but only to those that don't know the whole story. From another thread," I'm a much less is much more kind of guy".

More great info! Thanks Nick. My car is supercharged and running around 420 to the wheels. It would be nice to have a little more braking oomppphh at the track. Your thoughts on upgrading the MC make sense. Seems like the right way to do this would be to get the MC, calipers, rotors, wheel carriers, bearings etc... For those that are doing the GT3 or TT upgrades, are you doing the rears too? Seems like it would change the brake bias significantly if you just did the fronts. I wonder how they do it with the Brembo and Stoptech BBK kits as they use the stock MC??

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996 C2 / 996 turbo / 996 GT2 Brake booster ratio: 3.85 / 3.85 / 3.15 Master cylinder diameter, mm, F&R: 23.81 / 25.4 / 25.4 Master cylinder stroke, mm, F&R: 18.0 / 18.0 / 18.0 ABS all: 5.3 Pistons, mm: 40-36 / 44-36 / 38-32-28 Brake fluid reservoir, MY '01: C2: 996 355 013 00 tbo: 996 355 013 47 GT2: 996 355 013 00

I would like to install the 996 Gt3 MKI brake set at my 996 C2 2000. So please what pieces I need, in order to mount this brake set? Thanks

I forget to tell, I have the 996 GT3 MKI, wheels, in 8' ET 52 front, and 10' ET 65 rear with a spacer of 7mm, front and rear.

For GT3 Mk1 pads: 996 front pads are same as rears for Mk1 GT3, fronts are Pagid 2707. Have both in stock if you are doing track work - which I assume you will be with these honkin' brakes.

Any answers? I need to know if that is possible, to change the brake ssytem, and what I need to buy to do the conversion 996 C2MKI > 996GT3MKI ? For now I think in the front only. It needs only calipers , pads and discs of 330mm? Parts: 99635140991 DISC TRV FRT Left 996GT3 99635141091 DISC TRV FRT right 996GT3 99635142910 Caliper Breaks FRT Left 996 GT3 99635143010 Caliper Breaks FRT right 996GT3 Pads , I don�t insert the codes because there is so much options, in other brands.

You need to do front and rear. You also need the master cylinder. Lastly, you will need rear calipers and rotors, as well as front rotors, calipers, and wheel carriers. I did this conversion about 2 years ago on my 02 996 C2. Huge difference at the track.

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DD95, Did you by chance weight the different setups per corner? Would love to know the actual difference as I've heard anywhere from 5-15 lbs. per corner....

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Thanks a lot. Can you help me in this: 1- Can � do this by steps? First in front, and then at rear? Or I have to do the full conversion at the same time? The rotors are the discs? Or are another piece? Can you give the codes numbers of the pieces I need: - Master cylinder - front rotors - front left calipers - 99635142910 Caliper Breaks FRT Left 996 GT3 - front right calipers - 99635143010 Caliper Breaks FRT right 996GT3 - whell carriers - front left - Whell carriers - front right - rear rotors - rear left calipers - rear right calipers - whell carriers - rear left - Whell carriers - rear right Thanks

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I did not weigh them. But they are bigger, so therefore heavier for sure.

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I don't have the part numbers unfortunately. Yes, I would do it all at the same time if you are tracking the car. Having a monster set of brakes up front and puny rears could be a problem on the track. If it's a street car, then I wouldn't do this mod at all as you will see no benefit whatsoever other than it looking cool.

Ah ok. This is a car for street and track days too. I Try to find the codes. So to confirm this: You have the modification, to your 996C2 to 996GT3 ok? - The master cylinder is a individual piece needed? Then I need: - front: - 2 rotors - 2 calipers - 2 wheel carrier rear: - 2 rotors - 2 calipers - 2 wheel carrier It�s all I need?

After I did the total modification of the suspension, I mount the 996GT3 suspension on my C2, and huge different in track, I was very pleased. Now I have the idea to mount the 996GT3 brakes, however I need someone inform me the correct parts, I need, all the stuff please, if I have the codes to each part, it was great. Then I have to put some more power in the car. Thanks