mtksurfj

LiveFromNY

I'd love to see your car once you've completed the install. I've been thinking of going with the PSS9's but have been concerned about the ride...

RamVA

I just did this on a C2, I think you'll enjoy the install.

I set the height at 25.5" from fender-to-ground all the way around. I should have dropped it another half inch in back. There's been no downside to this height so far.

I started at F2 R3 (full hard being F1 R1) for the 250 mile drive to the track and first day of DE. I switched to full hard for the second day and return trip and was very happy with it. If I get annoyed with the ride I may go back to F2 R3, but I see no need to ever be any softer than that (given my preference for a firm, controlled ride under all conditions). I absolutely would not be worried about it being too firm, given the range of adjustment and the relatively soft springing.

It is very easy to adjust the dampers, so don't sweat it too much. The rears are a cinch to access, and once you jack the front and turn the wheel the fronts aren't too bad either (the adjustment is at the bottom of the strut). There's a rubber cap on the fronts, but I found I could adjust it OK without removing the cap. Ride height is a different story - such a pain that I'll be leaving it alone (to avoid the re-alignment).

I used the 996GT3 Mk2 alignment specs, but asked them to dial in as much negative front camber as possible (-1.6 each side). That combined with F1 R1 settings and new MPSCs led to a great DE. Car is otherwise stock.

mtksurfj

RamVA, let me see if I get this right,

25.5" measured from the wheel well center of fender to ground for the front
25" measured from the wheel well center of fender to ground for rear (why lower?)
996GT3 Mk2 alignment specs
Full stiff front and rear

My C4 is a 2000, does that make a difference? Does it matter that you were doing this to a C2 and I'm doing a C4?

I'm not too worried about ride comfort because my other car is a lotus elise... the C4 feels like an SUV on air suspension compared to the elise!

Thanks for the info!

RamVA

I say I should have gone lower in the rear because there seems to be more clearance in the rear and hence no downside to going lower there. I didn't have any oversteer issues, so it's not strictly necessary for grip, but in my mind lower is always better if there's no drivability issues. I think it will look better, as well, and as I understand it there should be some negative rake F-to-R. I measured as you described, though I understand there are better/more consistent measurement points. Also, given that the car was corner-balanced the heights are no longer precise all the way around - they were the starting point before the corner balance, and I'm not sure how far off they are now.

I used the 996GT3 Mk2 alignment specs BUT with the adjustment of maxing out the negative camber in front (no camber plates). This causes some hunting on the highway with the Cups on but does not seem to be a problem with the PS2s. Track handling was great, but of course I can't separate the alignment from the ride height from the springs from the dampers from the tires, since they were all done essentially at once.

I absolutely suggest full stiff front and rear for the track, perhaps softening a click or two at one end if needed for neutrality. Driving in VA (not in DC) I'm pretty sure I'll be able to live with those settings all the time (it is not my daily driver), but we will see. Given your situation you may want to go either a little or a lot softer for street driving (in NY/NJ). I am absolutely certain you will find a setting that's suitably soft for your taste in street driving, and the adjustments take a good bit less than 5 minutes. Ride stiffness should flat out not be a concern for anyone considering doing this.

In terms of installation, the C4 should be more or less the same, with the notable exception of having to (as I understand it) disconnect the front half-shafts. This sounds like a PITA to me. I recently posted a lengthy DIY for the C2, though without pics and obviously omitting this step. I'm not much of a wrench, but if you have a buddy you can knock it out in a (full) day.

In terms of the settings, I really have no basis for asserting what the differences might be (C2 vs. C4), so I'll share my thoughts in descending order of my confidence. First, I can't think of a reason you'd need a different ride height. Second, I'm confident you'll be happy with the ride quality. Third, starting full hard for the track still sounds good, but I suspect the front spring rates are higher so you might need to soften up the front relative to the rear to keep the tail active (or it might not be an issue, depending on how good a job of calibrating Bilstein did) - basically this falls in the realm of personal taste anyway. Finally, I have no idea if the GT3 alignment specs are appropriate or even work for the C4 - I recommend you get it aligned with a Porsche specialist.

I'm a fellow Elise driver, and my track experience with that car this summer was one of the driving factors in deciding to put the PSS9s in the Porsche. Before the change the car felt outright soft and heavy, and after (all of) the changes it feels fantastic. It's still not as devastatingly effective as the Lotus in the tight stuff, but it's very composed and controlled, confidence inspiring, and very, very fast. The 250 mile drive home felt quite comfy even on full hard after two days at the track, something I'd never say about the Lotus (which I trailer whenever I can).

All of that said - I could stand for the springs to be stiffer, and if I had it to do over again I might've gone with the KW Variant 3. I'm very happy with it, happy enough not to switch, but while my car was getting aligned I drove the shop manager's E36/8 M Coupe with the KWs, and they were damn-near perfect.

Sorry to windbag - hope that helps.

mtksurfj

Thanks for the info!

Not that I know anything much about suspension, but I expected forward rake, not backward rake?

I'm also considering doing the corner balance myself, shouldn't be too hard, just need to find scales, right?

Can you post the link to your write-up? That would at least point me in the right direction....

RamVA

https://rennlist.com/forums/showthre...88#post3458588

Conceptually and generically there's no great reason for a forward rake. It looks more wedgy or hot-roddish, but there's no reason to think it works better on track. If you look at/think about the classic 911 profile I think the backward rake makes more sense, but also keep in mind I'm measuring it in a relatively arbitrary way (by fender height).

If you have access to scales I guess you could give it a shot corner balancing. It's not difficult, per se, but it is a pain. The wheels have to come off to make adjustments and then go back on to get weights, and if you've not done it before I'm guessing it's a lot of trial and error. One thing I would do if I had scales, though, is get a baseline balance - you may find it's close enough without having to do any more adjusting, and you could save yourself some money by not getting it balanced.

Russ Murphy

It appears that the factory ride height for the GT-3 is actually a few millimeters higher in the rear (if you go by fender height), but both around 25.1". I'd imagine that's a pretty good starting point for a 996 that will see some track use if it's not too low for your driveway. I guess the key point is it looks like front and rear should be pretty close to level without scale data (corner balancing) to alter it.Panorama 996 suspension article

RamVA

Interesting and useful article.

I think if you stay in the range between 25 and 25.5 at either end you'll be OK. It'll look good, there'll be no issue with bump stop interference, and handling differences will be marginal (though lower is always better).

ngregson

I just fitted PSS9s to my 997 C2 (which had the base suspension) - my installer set it to 5/5 I think. I was also a little bit concerned about the ride before doing it, but found that surprisingly the car both handles AND rides better with the PSS9s. It seems more hunkered down and smothers the bumps better; although you can feel every bump, it's not jarring and quite OK for daily driving on mediocre road surfaces (eg. outskirts of Philly)