Bilstein PASM w/ Stiffer Springs?
 

Guys, I am currently running a 997.1TT Champion VTG with essentially a full aftermarket suspension. GMG Sways, Tarrett and GT3 everything else for the most part. There are very few stock parts left as far as suspension goes. Well one of the few items I am not 100% satisfied with as far as suspension goes is my coil overs. Let me first say, changing away from the PASM compatible model is not an option. I don't want the JW Coilovers or other brand. I want the Bilstein PASM models that I am currently running.

With that said, I thought I saw a few of the people here swapping out the springs in the Bilstein Coilovers to stiffer ones and still maintaining the PASM working. Under hard cornering, the car leans too much for my liking and I am thinking that stiffer springs in the coil overs should help fix this problem. Has anyone swapped out the springs in the Bilstein PASM models and if so to what springs? NASA Nationals is a few weeks away and I am seriously considering making this change after the last few track days I had.


See the attached photo for what I am referring to under hard cornering.


Thanks!


-Sayajin

Well, there's no doubt something funky is going on in the picture. It's not clear from your description if you are running the oem coilovers or the aftermarket Bilstein Damptronics. The Damptronics are far superior. I've never heard of people changing springs on them but don't know of a reason why it couldn't be done. If you go that route, please post which springs you use and their rates, etc.

How are your sways set up? Can they be further stiffened?

You might want to post this on the Race/DE thread where there are many more people with real-time suspension expertise. Absent that, I'd find a really good pro to help guide you through this. Good luck,

Thanks for the input! I am sorry if I was not clear. I am currently running the Bilstein Damptronics on my car and have been for over a year. I am running Medium Stiffness in the fronts on this photo and plan to stiffen to the highest to try and combat some of the lean.


-Sayajin

Chiming in to say that while the picture clearly shows a problem in suspension tuning--WHAT A COOL SHOT!:rockon:

Stiffer springs would certainly help and are probably the main thing lacking from the setup. Also keep in mind that springs are what control the attitude, dampers just control the motions--stiffer dampers alone should not be used to try and reduce body roll. Setting the front sway bar to full stiff and/or raising the ride height a little would help as well. Raising the ride height would bring the roll center up a bit, kinematically helping to decrease body roll under load by reducing the lever arm the center of gravity has on the suspension.

Sam

[QUOTE=Sayajin;11563204]Thanks for the input! I am sorry if I was not clear. I am currently running the Bilstein Damptronics on my car and have been for over a year. I am running Medium Stiffness in the fronts on this photo and plan to stiffen to the highest to try and combat some of the lean.

I went to a full stiff setup front and rear last year with my H&R sways and found it worked better than expected perhaps because the weight of our cars. Going full stiff in the rear will tend to induce a bit of oversteer but it would appear from the pic that you're probably understeering quite a bit in your current configuration anyway so that could be a good thing.

To me it looks like your rear-inside tire is in the air, so it looks like you need to run a softer rear sway bar and/or a stiffer front bar. The springs won't necessarily fix that. I am running different springs in the front that are narrower than the ones that came with the PSS10's as that will allow you to run more aggressive camber without hitting the springs.

I would also have the shocks tested/checks to make sure that they are OK as that could also let the inside rear to pick up. That is not what 911 should do :-)

I believe that's the front control arm brake scoop you're seeing, not the rear tire.

Is there any backstory to the cloud of dust in the picture? If the car took a trip over the curb or off course just before this, it would explain the extreme compression visible in the picture. It doesn't mean the car doesn't need stiffer springs, but the issue might be exagerated in the picture vs. reality.

No way the rear tire of a 911 is in the air in a turn. Physically impossible :)

I am going by one picture.. leaning like a '55 Chevy! :(

Not only that front appears too soft as you have stated, and I would question the alignment as well as well as tire pressure. That is a lot of under steer! And are you rolling on your side walls?

Guys,

Thanks a lot for all of the input.

I also agree that while the suspension itself needs help, it is a cool ass picture!

I am definitely going to stiffen the front sway bars as well as verify the max stiffness in the rears. I am currently running medium in the rear as I heard full stiffness on the GMGs make a huge difference in drivability.

In regards to the cloud of dust, I have to be honest, I don't recall if I kissed the rumble strips or not. However I was "told" that the car was leaning through several corners and not just this one.

As far as the alignment, I had the tech at the track give me his thoughts and he said based upon the tire wear on the R6s, he felt the alignment and inflation was correct.


-Sayajin