De Jeeper

Correct the geometry is exactly the same so u can get the same performance that porche designed into the gt3 suspension in a c2 by just bolting in the parts. Although the overall aspects of cars performance may not be the same as a gt3 due to all the other differences in areo, brakes and drivetrain.

TheChunkNorris

Absolutely but at least the suspension adjustability at the OEM aspect will be similar if not damned near spot on.

yaz996

Don't forget the solid bushing rear subframe if you're going for the exact geometry.

TheChunkNorris

That too. Pretty sure I have semi sold engine mounts but not sure of the others.

theprf

Having just done this on my GT2ish, there are so many subtle differences that I doubt it's worth it if you have a RWD car.

As an example the GT2/GT3 front wheel carriers take the 142mm bolt spacing Turbo/GT2/GT3 calipers directly. BUT, you need to use GT2/GT3 fitment rotors. The GT2/GT3 wheel carriers position the rotor disk 2mm closer to the center of the car. The much cheaper and more readily available 996/997 Turbo rotors don't fit.
What I did was to get some rotor spacers laser cut out of 304 Stainless so I can use the Turbo rotors. There are no slotted, undrilled GT2/GT3 rotors available unless you go to 2-piece rotor setups. The spacers let me run the 997 Turbo 350mm slotted Sebro rotors which are downright cheap in comparison. I have few extra sets of the rotor spacers... I had to by 5 sets.

Another little difference is there is no provision to mount the front drop links to the GT2/GT3 wheel carriers, they must be mounted to the strut bodies. When using motorsport struts that means you'll need to use a kit like the Tarret extended drop link kit to have any front sway at all. All the little bits like brake hard lines and brake line mounting parts are different too. I have all the part#'s to get this stuff from Porsche.

The GT2/GT3 front wheel carriers are nicer for brake cooling, the heat shield is much smaller and just to protect the ball joint and the outer tie rod end. There is a little fiberglass blanket that gets wrapped around the ABS wheel speed sensor otherwise it would get cooked from the rotor heat.

De Jeeper

Kinda. The solid mounts r the same thickness as the rubber bushings but they do have sleeves to prevent over compressing. I would think it would be minimal in the geometry but bigger on the performance side.

theprf

996 Cup uses a shorter solid bushing and the top of the rear subframe is milled down some. Both of these move the body tub closer to the subframe. Cup cars are really low.

TheChunkNorris

Holy cow that's a lot more involved than I ever thought for that car! I'm in weird place with the brake set up. I bought a kit similar to Jason's that uses 380mm GT4 rotors, along with a bracket. Been asking Aaron a bunch of questions about suspension set up since he's done a lot of it.

yaz996

The solid bushing subframe that is currently stashed away in my attic brought everything up closer to the tub enough that the swaybar interfered with the IMS Solution oil feed line. When I posted it for sale last year, someone commented that it looked like it was from a cup car.

De Jeeper

Maybe im wrong and its the reason i had such of an issue with the gmg rear sway bar?

theprf

Could be. Measure the gap from the subframe to the body tub above the driveshaft when you have a chance. I'll measure on my car which has stock subframe and rubber bushings later.

barbancourt

Serious question, is there really a benefit to converting to GT3 suspension as opposed to upgrading the C2 suspension with quality components? I would imagine that assuming aero is the same, a properly modified C2 suspension could out handle a stock GT3, no?

De Jeeper

as i said earlier u can replicate the gt3 spec or improve on it with aftermarket easily. I would not buy a stock gt3 suspension unless u r a purist. The spring rates r higher and valving is tighter, sway bars r adjustable. Remember the gt3 is lighter in most cases and u would need an aerokit to get similar aero characteristics.

TheChunkNorris

I know everyone's case varies and I know you're not coming at me... it was a good question. In my case, I'm a weirdo and I analyze things like a weirdo. Ended up paying 500.00 for the set and all they really need are the hats. Feels would be the next best alternative to say a set of Ohlins or PSS10 being the most popular. Are a set of Feels 700.00 better? I don't know? Will I able to outdrive a factory GT3 suspension with the other Tarett upgrades? Absolutely not. By the time I'm done refreshing everything, the cost would be around 2500.00 which includes the LCAs and all the Tarett parts which I believe to be pretty damned good. GT3 sways are also in that number.

theprf

I think you may be underestimating parts cost, if you only have the GT3 front wheel carriers. You're going to need:
2x GT3 front tension bolts: 99634113104
2x Front wheel bearings 99905305405
2x Front wheel hubs 99134160503
2x Axle nut 99908463402
2x Pinch bolt 90037813809
2x Pinch bolt nut 99908444509
2x Speed sensor bolt 90006711709
6x Brake backing plate bolt 99921711609
1x Left air baffle plate 99635181590
1x Right air baffle plate 99635181690
1x Left heat protection for speed sensor 99660623590
1x Right heat protection for speed sensor 99660623690
2x front wheel speed sensors 99660640600
2x Wheel bearing retainer lid 98633166120
8x Wheel bearing lid bolts 99921704209

Then if you want to run front brakes you'll need these parts:
1x GT2 front left brake pipe 996-355-581-9B
1x GT2 front left brake pipe support 996-355-501-06
1x GT2 front right brake pipe 996-355-584-9B
1x GT2 front right brake pipe support 996-355-502-06
2x Brake pipe support bracket screws 900-067-117-09
4x brake caliper bolts 999-067-047-09

Then if you want to use 997 Turbo front rotors you'll need a set of my 2mm rotor spacers.

All of these parts were still available when I bought them in January 2022. Of course you can reuse some parts from the C2/Boxster front wheel carriers like the wheel speed sensors, the wheel hubs, and the tension bolt.