fuenfer

I recently corded my PS2s on my 997S, and decided to finally get a set of Michelin Pilot Sport Cups. In moving to these tires, however, I have been told by many (on Rennlist and otherwise) to get GT3 control arms to dial-in the proper amount of negative camber. Since I will be spending the money to get the GT3 control arms in, I am seriously considering upgrading other aspects of my suspension at the same time.

Someone that I highly respect also suggested that I might want to do GT3 sway bars. My shop, on the other hand, has been pushing me to do the JIC/Cross suspension for the car along with the GT3 control arms. Does anyone here have experience with the JIC/Cross suspension, whether good or bad? I do not race this car, but do about a dozen DE days a year. Any thoughts would be greatly appreciated.

I am also considering purchasing the 997 GT3 mkII if/when available, so cost is definitely an issue here (i.e., I don't want to spend a lot of money on a car that I might be getting rid of in a year) - accordingly, I may be interested if anyone is selling a used suspension.

Steve Weiner-Rennsport Systems

Hi,

If I might offer an opinion, along with the others you will undoubtedly receive,...

MPSC's require a bunch more camber than PS2's and your stock suspension doesn't have sufficient adjustment to hit those targets. The GT-3 two-piece control arms (and upper monoball mounts) will get you in that ballpark.

GT-3 adjustable swaybars afford the ability to tune the balance of the car to your preferences and skill levels. Good stuff.

I'm not a fan of the JIC/Cross suspensions due to QC issues and ride quality so I'm not one to ask,... We use & recommend various Bilstein and Moton suspension packages that IMHO, are better solutions.

All that said, if you are contemplating the purchase of a GT-3, I would be careful about what you do and what components you choose. Some items already come with a GT-3 and some items can be used on the newer one.

mglobe

I've got only a very little bit of experience with the Cross Competition system in my 996 track car. So far I've been very happy with them. Mine are sprung very stiff though, and are not intended for the street. I've spoken with several people who have used them for club racing and have been very happy with them.

tkerrmd

I have the full JIC race setup and am happy with it. it gives you the camber plates for the camber you will need. the Cup tires need neg camber which you cant currently get. the JIC set up is as good as it gets before you go to a moton type suspension for 4 times the cost.
for your car the JIC suspension and a rear GT3 swaybar would be a great set up. and several guys with your car that I run with at the track have exactly that. As do I.

BrokeAss

While I was pretty happy with the performance of my JIC system, I did manage to destroy two or three of their shocks. ...but then again Sebring is hell on suspension parts. Maybe I should have stayed off the curbing?

Bryan Watts

The curbing is where I drive to settle the car down at Sebring.

fuenfer

Thanks for the advice. Are there any Bilstein/Moton solutions that are as "affordable" as the JIC/Cross solution? I haven't heard the greatest things about the damptronics, and intend to stay away from those.

And also, what sort of quality control issues are there with the JIC/Cross?

fuenfer

My shop is recommending that I get both the GT3 control arms and the JIC/Cross suspension. Given that the JIC/Cross suspension can get me the negative camber I need, is there any reason or benefit to changing the control arms?

RonCT

I've been through this already. I'd get the control arms with 3mm shims first and see how that treats you before touching the coil overs and sways. I experimented with alternative shocks / springs, OEM GT3 sways, and honestly, the best combination I got was right back to OEM shocks / springs with the GT3 control arms and a good alignment.

Problem with GT3 sways is they are not a direct fit. You have to fiddle with new aftermarket drop links to get them in and working without hitting anything. Then you may have issues with their impact on the OEM shocks & springs. Maybe the H&R front and rear would work - that's one combination I didn't try.

Point of reference - I've been in black for years, and was able to coax 1:02s at Lime Rock and 2:16s at Watkins Glen in a stock 997S with control arms, pads, and street tires (PS2) while I was still learning how to drive a Porsche. Very potent numbers and that's with the stock PASM suspension and OEM sways. Once sway settings tightened up, that threw everything off for some reason. Then we tried alternative shocks / springs and it never got back to where it was bone stock. Taught me a new appreciation for the amount of R&D that must have gone into PASM.

I'd check into the 2009 OEM PASM -10mm shock set. I've read it's even better and you'll get a lower ride height as well (not a fan of lowering springs).

No idea on JIC for a 997S, but I'll say I really liked it on my 964 -- though it did get unsettled in hard braking on imperfect surfaces.

ECS

+1 on Ron's comments. I did GT3 control arms, stainless steel brake lines, GT3 air ducts for the brakes in the front, 6GT2 ducts in the rear and that's it. I am sticking with PS2s and MPSC don't come in the correct size for Carrera S wheels. If you are going to maybe get a MKII GT3 don't do anything more than this. Its perfect unless you really want to go at it.

Pennington

Earlier this year I corded a fairly new PS2 in one day, on a bone stock 05 C2S. After talking about it with instructors and finding the right mechanic. Here was my reasonable solution, we went to the most aggressive alignment with the stock suspension components. Put on new Toyo R888 in the largest size that would fit 255/35/18 and 315/30/18. What a completely new car on the track after about 8 track days the tire wear looks good and the car is an absolute blast. It is my first set of race tires and I had no idea what that single change would mean to what you can do with the car. Start with small simple changes.

RonCT

Wow, if you corded a new PS2 in 1 day, your OEM alignment was WAY off. When I took delivery of my 997S, I already knew from this forum that the factory was less than perfect and the dealer was authorized to re-align at the request of the client if within 60 days or 2000 miles (whichever came first). So I started off with as much camber up front as I could get from the OEM control arms, fixed the toe, etc.

The GT3 control arms make a huge difference in being able to get the alignment optimal for street / track. I don't remember the exact figure, but I think I had about -2.3 up front after the $1300 investment in the control arms, labor to put them on, and alignment. Took care of the understeer, though there was still just a little way up high as a safety valve - better that than snap oversteer

mkk62

great topic was just about to pull trigger on JIC/cross suspension ...ROnCT 's experience is what i wondered about..thanks Ron for saving me the grief....i maximized the neg camber up front which helped alot as i also corded a set of ps2's in one day earlier...3rd day today on the r888's and not overly impressed but still need to get the gt3 control arms to mazimize their capacity. Road Atlanta next month....

DanR

I know it may not be your first thought but rather than spend cash on GT3 parts which you will no doubt lose lots of money on have you thought about trading to an actual GT3? May not work out much more in $ terms and will no doubt depreciate less in the long run. Just a thought!

fuenfer

Ron, is the $1300 investment for just the front control arms, or is it for all four? Is it necessary to do the rears, as well?