When I acquired my '07 997 TT last March, I noticed a "boing" noise when turning in and parking it in my garage. Since I needed an inspection for the state I asked my dealer to check it and he said, "Coilovers are notorious for that, although you seem to have more noise than most."

This started a month's long search for a solution, and unfortunately the answer I was getting was the same: coilover springs bind and make popping boinging noises.

Well I just could not accept that and continued looking and finally found a post:

https://teamspeed.com/forums/991-997-996-turbo/63945-porsche-997-tt-anatomy-getting-perfect-997-turbo-suspension.html

Unfortunately there was no information about the actual parts and while I tried to contact the poster (no response), the shop (from a banner hanging in one of the pictures - but out of business) and even tracked the poster IRL but got no response. I posted in a suspension thread and continued looking. I finally found them at Patrick Motorsports and 1 hour later Mitchy on this forum posted that Performance Shock Inc has them a bit less expensive as well as another poster on R-List that said Torque Solutions and Tarret were other alternatives, though I could not find the exact parts looking for either manufacturer.

The parts (shown on the right compared to the stock mounts on the left look like:




The parts I ordered were:




At Mitchy's suggestion I also purchased some thrust bearings that Swift Springs makes, The kit you'll need is Swift PN#: 744303 (Spring Thrust Sheets Kit 70mm 2.75"). I got them at FRSports for about $25. I moved the blue plastic thrust sheets that came with the coilovers to between the helper springs and their points of contact.

Interestingly enough, even though my dealer said they were Bilstein PSS9's they were actually Techarts. (Bilsteins with Techart springs). While I have not found much information about the differences between Techart springs and the the stock Bilstein springs, I have no complaints in how they perform, especially with a DSC added.

Another interesting item is that I found the drop links were installed on opposites sides with the link toward the inside of the wheel well instead of to the outside. This put them at a severe angle and answered another, albeit it much more concerning problem, a major clicking noise when turning very hard in a parking lot. I though it might be CV joints or worse, a differential. By moving the links to the correct side, that noise is gone also.

One unexpected thing (though now that I think about it, I should have expected it) is that turn in is so much easier, the suspension almost wants to pull down into the turn on sharper turns. Nice improvement.

One last item of note: While the word was there would be more road noise, I have not noticed much if any. Now the car is already lowered and running on 20's with tiny sidewall tires, so my experience may not be definitive.

The only ramifications of doing this are:

1. Need to drop the suspension back down a bit (raised it about 2 inches) but since they are coilovers I am not anticipating any issues (waiting on wrenches since whoever paid for the coilovers to be added to the car neglected to include them when I purchased the vehicle)
2. Need for an alignment (which most suspension work would require anyway)

So if anyone is telling you that you have to live with noises from your coilovers, they are mistaken. Also, a lesson to be learned is:

1. If you want it done right (and you have the skills) do it yourself

or

2. Take it to someone who knows what they are doing

Ed

 

aren't the Thrust Sheets enough by themselves to resolve this?

 

There were these blue thrust sheets already there (the Swift ones were a combination of a metal plate and a plastic one) and there was still a noise.

My impression is that the ball bearing strut mount in combination with separating the coils from the lower part of the stock mount with a different hat and placing the hat in direct contact with the bearing adds up to the ability for the strut to turn easily, placing very little torsion force on the spring. It may even be that the reduction in twisting force alone without the extra sheets would have solved it, but for $25 that was a no brainer.

I had asked about thrust bearings before doing this and the feedback I got was that since there were already thrust sheets there it wouldn't have done anything. Of course this is in combination with other advice gleaned during the same time period that I just had to live with the noise. I can see where a roller bearing type of thrust bearing would have a similar effect as the new hat/mount combo, but I do get the extra benefit of going with more negative camber if I want.

The only other factor for me is that removing the struts, while not impossible, does require some hours worth of work, and I did not want to do it more than once for this solution. While the $650 total cost wasn't minimal, my happiness with that embarrassing noise gone is worth 10x that amount.

Ed