GT3 Coilover question

Anyone know what I would need to do to get Gt3 coilovers on my 99 C2? Has anyone done this? Thanks.

The GT3 suspension is different than the 996 suspension. I don't think you can do just the GT3 coilovers without changing a bunch of other parts. A better alternative might be a set of Bilstein PSS9's with some GT3 sway bars.

You will need the uprights (spindles and hubs) from a GT2, GT3, Turbo or C4S (they are all the same). They can be mounted on the regular 996 lower control arms, but you should get GT3 lower control arms anyways to adjust the front camber. The front brake mounting is different on the Turbo/GT3 uprights, so you will also need to upgrade to at least Turbo brakes.

Thanks 02. Have you done this mod? If so, is it worth it or are regular PSS9's just as good?

I spent a while with the parts department at my Porsche dealer going through this when I upgraded to GT3 control arms (why wasn't there a FAQ on this?). I had an opportunity to pick up a used GT3 suspension very reasonably from a car that upgraded to Motons so I went through the same decision you are going through. Struts arhave a different mounting location that changes the caster. This is why GT3 control arms have to be flipped backwards on our cars to correct the caster. The best solution to bridge the gap is to get the rest of the parts from a wrecked Turbo or C4S. I run neither. I started with a ROW M030. I am still running a ROW M030 and I am not going to change. I like the ride/handling compromise with the ROW M030. Getting a proper alignment will make a much of a difference than just dumping a bunch of money into other suspension parts from here. As I was considering the upgrade you are, I upgraded to GT3 control arms and fixed the alignment for running MPSCs. These cars are very camber limited in the front end. In order to get a set of MPSCs to run right on the track, you need at least a degree and a half of camber. With -1.6 camber front and -1.9 rear, I have been running in the Yellow and now White groups with the GT3's. With the additional camber, the car no longer feels roll limited and is perfectly neutral on the skidpad. Surprisingly, a pair of contorl arms and an alignment fixed all my suspension woes. I also had an opportunity to pick up a used pair of GT3 sway bars with TRG end links, but the car is already balanced. There is no point in developing the suspension further. I am spending my money in other areas like a Techequipe rollbar, GT3 seats and harnesses to hold me into place properly while driving at the limit. Recently I drove an 04' GT3 and I found that the stock suspension on the GT3 and my setup feel almost the same. Strangely, my car is a little harsher in the back end that the GT3; but the steering feel is remarkably the same. Spring and dampening rates are very close. No those cars are not the rough riders some people are indicating they are. My .02 is to decide 1 of 2 things: either consider moving up to a GT3 (I have seen several 04's for under $80K recently) or look at going the PSS9 or ROW M030 route. The PSS9's offer ride height adjustment which could be an advantage if you run smoother roads than I do. They also have adjustable shocks so you can still get a softer ride.

For a car that is used mainly on the street with occassional track use, PSS9's are hard to beat.

I only really use the car for AX and DE. I want the car to be very good in handling but I also want it to be streetable.

Give these guys a call and/or visit. http://www.sharkwerks.com/main.php

02, thanks for the info on getting gt3 coilovers installed in my car. It will help in my decision on what to do.

Thanks too earlyapex.

don't get the gt3 coilovers. people here, in the gt3 forum, have complained that they are underdamped/oversprung. get motons, jrzs and you get a better suspension. if you must, yes you can use gt3 coilovers. no need to use the gt3 wheel carriers, just use the 996 carriers. fronts are just strut inserts and the rears are just shocks. nothing special about it.

you don't need the uprights from the gt3 only if you wish to upgrade to the gt3 brakes. you can use the 996 uprights/wheel carrier. the gt3 sturt inserts right into the wheel carrier. you use the 996 pinch bolt/sway bar link. you don't need to use the gt3 control arms (which i have) and shims to get more negative camber. in fact if you use the shims you will increase caster. more caster = slower steering and the possibility of wheel clearance issues. it's better to flip the spring top mounts or by slotting the mounting holes. nice thing about using the gt3 control arms is you can use them flipped.. left to right.. so that you can use the front mounting hole, pushing the wheel towards the rear of the car and decreasing caster and can eliminate any wheel clearance issues.

agreed. if you want an upgrade to the pss9s there are jrz single adjustibles as well. they are better suited to track driving and are still pretty good on the street.

Have you done this brake upgrade? I had a set and the mounting flange is in a different position on the GT3/C4S/Turbo uprights. You will need a custom adapter to get them to work on a Carrera upright or order the parts form the PCCB setup on the 987 Boxster and Cayman. You are correct that you don't NEED GT3 control arms. If he decides to go with PSS9's he can get camber plates that will add a degree to the range. Those of us with stock type suspensions have problems in that camber plates like the TRG and Weltmeister won't work with the larger diamter springs. This leaves GT3 control arms as the solution. In order to correct for the caster, they do need to be installed flipped from side to side (RS style) on a regular Carrera. I know personally for a fact that if you don't do this, they will rub on the front fender liners. Keep in mind though that more caster is not a bad thing. It does increase steering feel, but increasing caster increase camber while turning.

no, i haven't done the gt3 brake upgrade. yes you i are right that if you want turbo or gt3 brakes yo need to change the uprights OR use a custom adapter. i have stoptech brakes with 355mm rotors. it utilizes a spacer to bring the brake caliper out to the new rotor diameter. what i was referring to was that you don't need the gt3 upright to use the gt3 struts. ah, i was only referring to the gt3 suspension on the 996 not 996s with fairly stock suspensions. true, camber plates will only work with 2.5"OD springs and are not compatible with large diameter oem springs. actually, my gt3 control arms are in mounted in the center hole (not using any shims). i only have fender liner issues when at full lock. NJ-GT on the gt3 board also had your problem. the extra shims increased the caster and pushed out the wheels enough to cause the well rub. IIRC he ended up taking the shims out and slotted the top mounting holes to achieve -3 degrees camber. true in a camber challenged car. i have -2.5 degrees up front which could increase to -3.5 degrees or more while turning. depending on the tire, the contact patch would be sub optimal.

I researched the PCCBs on the Cayman and they also use a different upright (from the 997S). If you look at the diagram they note the different uprights for option I450. Coincidentally, 450 is the option code for PCCBs.

Thanks for the information karlooz. I actually picked up a set of GT3 coilovers on the cheap, but I'm still up in the air about using them. So to to recap, GT3 coilovers will work on a 99 996 without any special parts, right? They can also work in conjunction with after market camber plates as well, right? How far off in performance are the GT3 coilovers in comparison to the PSS9s (I'd probably opt for this if I pass on installing the GT3 coilovers)?

My 2003 996 has 2004 GT3 coilovers. Needed front strut bearing mounts from GT3 and sway bar mounting brackets in the rear since the bars connect to the shox differently.

like jim3 mentioned, you'll need the strut tops but they are probably already included in the kit you picked up. if the sway bar drop links won't work with your 996 sway bar then pick up a set of adjustable drop links from TRG.

Thanks guys...just one last question. How do the GT3 coilovers rate vs the pss9s or x74 kit?

i think the pss9s and the gt3 coilovers have similar spring rates but the pss9s have rebound adjustment. some of the the gt3 guys on the gt3 board have mentioned that the gt3 coilovers are under dampened. do a search. maybe the pss9s are a better bet.

Since I repeatedly see misinformation being posted about useability of the GT3 suspension in the C2, I wanted to set this straight for anyone contemplating doing this as you do not need to change a thing on your car, they bolt right in just like a ROW M030 or PSS9s would. A bit stiffer than PSS9's btw. I just had a set of 2004 GT3 takeoff coilovers/springs installed in my 99 C2. Direct bolt in. No part changes needed whatsoever. The front strut mounts had the bolts rotated into the positions that give additional negative camber. Car is yet to be aligned yet but the range seemed to be from -2 to -3.5 up front. Will know tomorrow.