Hello all. I did some searching, but I may not have the correct terminology to find what I am looking for.
Does anyone know whether the lower track arms, aka tuning forks from a GT3 will fit out cars if we are running GT3 LCAs?
I have GT3 Lower Control Arms on my 2007 Cayman S, and the other day I was doing some tweaking on the suspension settings. The car also has KW V3s, and I changed up the ride heights a bit, as well as switched the GT3 LCAs to the alternate castor setting, which took castor angle from 6.5 to 7.7 degrees . That in combination with bringing the rear ride height up to 20mm or so higher than the fronts made a noticeable improvement in high speed stability. I think the rear end was getting some bump steer at the lower ride height, but it could also have been aero related with both ends riding at the same height removing some of the downforce. Could also be a combo of both, but either way the car is much more manageable on the autobahn now.
Doing the job was a bit of a pain though, as in order to install GT3 arms on our cars without changing the track arms, AKA tuning forks to some apparently, you need to install small spacing "pucks" as the thickness of the bushings is larger on the normal cars than the GT3. These Spacers are a real pain to get lined up properly in order to reinstall the bolts. It took about 20 minutes to figure out how to get the first one to cooperate, then another 10 on the other side to get it all lined up. Way more time that one should be spending installing two bolts. LOL!
The reason I am wondering if it might make sense to go with the GT3 track arms is because I think my factory ones might be shot. I'm getting an occasional metallic clunk out of the front right suspension, particularly on rather sharp bumps like mismatched concrete seams. Literally everything in the front suspension but that track arm is less than a year and a half old while they are original I believe, so I suspect the ball joint might be shot. I tried manipulating it a bit while I did the job, but I couldn't really tell if they are shot for sure. Felt a bit squidgy though.
A little research turned up a part number of 99634104306 for the GT3 arms vs 99734104300 for the stock Cayman S version, but I couldn't find mention of a retrofit to a 987 car, so I am not 100% sure if the lengths and ball joint size are the same as the standard model ones in order to fit properly. Oddly, the GT3 arms actually cost less.
Anyone have any experience to share here?
So, I decided to take the plunge and ended up answering my own question.
The answer is that yes, the GT3 diagonal/track arms will fit a 987 that has GT3 lower control arms installed. There is one caveat though. You also need a different bolt to connect the track arm to the LCAs. The normal one is too long, and not threaded far enough down to make things work.
I don't think there would be much a performance gain if your track arms are not worn out, but mine definitely were. Clanking noise over sharp bumps is gone, and the car tracks a lot more true on the Autobahn now as well. Ease of installation is massively better than the old puck solution though.
For anyone looking to do the job in the future, you would need the following part numbers
99634104306 Track/Diagonal Arms AKA "tuning forks" They really do sing by the way
90037813501 Control Arm Bolt
Optionally, you can also add part number 90038001201, which is a new nut for the control arm bolts to keep everything consistent.
Of course, keep in mind this will ONLY work on cars with GT3 front lower control arms.
