OK. I got great info on my previous thread and I read a whole lot of older threads pertaining to suspension mods but I still cannot find clear answers to the following questions pertaining to the OEM specs:

(1) On a C2S, can PASM be upgraded to SPASM (forget about the LSD part) - which is lower and stiffer - I do not have access to PET but in the literature, it seems that the only difference is the spring rates, so maybe different springs. Anything else different? How did they solve the geometry change problem (alignment range) on a lower suspension?

(2) In my previous thread, some people mentionned swapping GT3 suspension parts on their C2S to improve the suspension. Reading on the 997.2 GT3 it seems that it also has some form of PASM. Would it be possible to upgrade a C2S PASM to GT3 Spec PASM - which I assume is lower, stiffer, and lets go of the rubber bushings? What is the difference between the GT3 suspension and the C2S suspension parts wise? To the people mentioning they already did "this" all or in parts, what did you change? Just the C2S spec front/rear control arms for equivalent GT3 parts?

Essentially, I would like to know what tweaks Porsche is doing on the different 911 flavors as I would rather go OEM before moving into 3rd party territory.

Thanks,

T.

P.S.: I guess I need to buy the PET CD as it seems it could answer most of these - but it is BO'ed at Suncoast.

 

I don't know the technical; specifics to answer entirely but what i do know is that the Gt3 has a stiffer suspension, less soundproofing , stiffer clutch. completely different (gt1 dry sump) enfine with more Hp, torque , and mid range power, is ligher , more balanced ...

No matter what anyone does to a 997.2S it will improve the car but it won't ever be a Gt3. What anyone does to a Gt3 it won't ever be a gt3RS.
I realize that a lot of guys here track their cars and i don't but if I did I woild not keep my 997.2S . You'll spend an infinite anount of money trying to make the car what it can never be .

 

yrralis,

I completely agree with what you are saying.

My goal is not to make a C2S a GT3 since I really only track the car only 6-8 DE events a year, and I need those backseats for my favorite small passengers.

I see this as a law of diminishing returns as there are probably a couple of items that will make a fairly big difference - but if you change everything, what is the point, just get the other car.

I am just trying to narrow down what OEM changes I can do to improve the suspension a bit. I want lower, stiffer, and less "fuzz", probably something like SPASM would be but with metal bushings instead of rubber (a couple of GT3 parts?).

Regards,

T.

 

I won't mention here who sent me this, but I asked in an email what he had done to his car to consider it "track ready". I'm not a judge of what is need and what isn't to make a car competitive. However, here is the list he sent me:

-AWE Mufflers
-AWE 200 CEL Cats
-AWE Headers
-BMC Drop-in Filter
-GIAC ECU Tune
-OEM Short Shifter
-OEM GT3 Bumper
-OEM Aerokit Wing
-HRE P40 (8.5x19 & 11x19)
-Bridgestone Potenza RE-11 (235/35/19 & 305/30/19)
-Pagid Yellows
-Bilstein Damptronics
-RSS Sway Bars
-RSS Monoball A-arm kit
-RSS Solid Thrust Arm Bushings (Front)
-RSS Adjustable Thrust Arm Bushings (Rear)
-RSS Adjustable Upper Control Arms
-RSS Adjustable Toe/Bump Steer Kit
-Corner balance

 

The diff between cars involves chassis, suspension sub-assemblies and coils/dampers.

- Coils/dampers are easy to change within a certain range of parts.
- Suspension sub-assemblies, not so easy to change.
- Chassis are chassis - you got what you got.

Why change anything? Do you have a documented reason to change something to meet your driving goals? Have you tried a stock C2S in both suspension modes? In my experience, in most US roads, PASM Normal mode is very good. I only found a handful of roads/tracks where PASM Sport mode excels. SPASM is sttiffer (even in Normal mode) and risks ground rubbing more often.

 

if you want keep PASM in the car working - get in touch with TPC and get their modified re-valved damptronics with stiffer springs, as well as their or GMG sway bars and optionally use GT3 LCAs, GT3 upper mounts and monoball rear toe arms. those are major parts that will eliminate most dynamic camber and toe changes. next step is to get rid of all rubber bushings you have - dogbones, thrust arms, etd, replace all with steel monoballs, replace rubber GT3 LCA ends with billet steel monoball ends as well - but that is for track only cars.

other way that a lot folks do on track only cars is to throw PASM out (disable it) and go with race grade moton/jrz/ohlin shocks with 600lbs/800lbs springs. consult with pro racers in your area and pro shops who do such a work - it is too big of a decision for a forum advice. any rebuilt suspension will be as good as builder who designes it and puts it all together.

if your goal is to go with strict stock parts - perhaps it may be possible to replace whole undercarriage with GT3 one but it may cost a fortune.

and as it was correctly noted above - stock pasm is quite good for street and needs no improvement really.

 

That is quite the shopping list. Looks very similar to my list to Santa so far.

I have been looking into the RSS setup with either damptronics or just springs. I guess I can always revert to OE if need be.

It depends on what your definition of "documented" is...

I used to have a 2002 C2 with M030 and RoW springs and I liked the feel better. The car felt, for a lack of a better word, "tighter".

I went to a track event a couple of weeks ago with my 09C2S and on a track with lots of elevation changes, during turns, the car felt bouncy and the handling was a little "fuzzy" - comparing to what I had.

This is the only "documentation" I have. But there is no question that I need to do a bit more track driving with this car to get used to this setup and establish a baseline before turning the universe around.

Yes, I would rather have two settings to "play" with.

It looks like the GT3 thing just isn't doable - might as well do like yrralis suggested at that point: get a new car.

That being said, as much as I would say that this is completely track/performance related, it is not. The truth is that as a driver I am nowhere near the capabilities of the car, and all I am doing it probably looking for ways to fix the shortcomings of the driver - probably screwing up the car in the process... But experimenting is what makes things fun.

I would, however, like to see the car sit a little lower as it might be a psychological factor. I do not mind a stiffer ride on regular roads and hence, why I was asking about SPASM first.

Thanks for all the feedback, it always amazes me the amount of knowledge that can be found on these forums.

T.

 

Did you turn PASM Sport ON? It shouldn't be bouncy if you did. And the handling is crisper on good surfaces. The problem with less compliant suspensions is that on the typical street/road they lack compliance and gripping is less good than it should be. Many misinterpret that.

 

Yes, I did.

I can't really judge with what is going on with PASM on public roads as small potholes in my neck of Canada could hide a hummer. "Smooth" is not an adjective you can use to describe roads here... I like a stiff suspension so I find myself using sport mode more often than not but I can't really tell about turn in performance on the streets.

My only _real_ experience with PASM in "Sport" mode is on the track (Calabogie, ON). I did a run without "Sport" mode on and it was really, really bouncy. With "Sport" mode on, the car settled down but I still had this feeling of "floating" a little bit.

I can't wait to be on the track again to be able to verify and see if it is just because I am expecting something "different" because of my previous car/setup and need to adapt myself to it, or if it is really something I do not like and need to fix. I think that part of the problem is that the previous car was like an old shoe and I got so used to it. Plus, there was a hiatus between the two cars, which may be affecting my perception.

I was also just thinking that my front pressure might have been a bit low too (27-28 psi cold). Although I wasn't rolling the thread (I was right at the outer edge - using shoe polish) but I am thinking that it may have been a tad soft since I was seeing quite a bit of understeer. So I'll play a little bit more with the pressure next time and make sure I get an alignment done when I do the tech right before the next DE.

What is so cool about these cars is that you can actually feel things,

T. (who obviously needs to learn to drive properly before tinkering with German engineering)

 

I did the Bilstein Damptronics to my car and the difference is significant. It met all the criteria described above and works with the OEM PASM settings . It is also ride height adjustable .

 

You are questioning suspension behavior and drive w/ 27/28PSI when it should be 34PSI ?!?

 

You bring a good point adias.

You mentioned you run your fronts at 34 psi on the track? can I ask what brand/model/size tires you run? is that cold or warm pressure? what ambient temperature?

To your point, I just want to reassure you that I did not just go about this randomly; here is how I proceeded (please correct me if I did not do this correctly):

First, let me say that someone I know and respect recommended about 31 cold for the front on the PS2's. I took that as a baseline but still wanted to see the effect of pressures on the track and validate that number.

My front pressures were about 36 psi cold (which is on the high side) before the first session (5x25mins day). I tried sport / non-sport first, and since that did not quite do it, I then played with the pressures.

Looking at the shoe polish marks I put on the side of the tires on each session to see how I was going to the sides of the thread (since I do not have a pyrometer), I let about 2 psi out three times with warm air. According to this, I should have had at least 2 sessions near the sweet spot. #3 and #4. But I was getting tons of grip at the end (and was eating rubber like candy). But the general handling feeling was the same.

I agree I over-corrected a bit on the pressure for the last session but I still think my conclusion is *somewhat* valid.

But, like I said, I am by no means an expert - more like a competent/incompetent, if I was to quote another thread - and still learning how this all works, so if anyone has some suggestions, I am all ears and ready to try.

At this point, I think I will just stay stock on the suspension for a little while, I will get an alignment done before the next session to make sure it is a-OK and start from there.

Thanks,

T.

 

also the Sport PASM has larger sway bars and stiffer springs...shocks might be valved different but nobody really knows.

If you really want a street/track suspension go straight to Moton coilovers and Porsche Motorsport suspension parts and you can check into GMG/RSS and Tarret suspension bits.

 

The most important and effective item is missing from this list..............

Driver Ed.

 

Thanks mdrums,

you are rightm I checked in PET for PASM/SPASM differences and the dampers are different (valving?), the springs are different, the control units are different, and a whole bunch of other stuff (washers, sway, wishbones...). I am not an expert in PET but the list was pretty big.

The net net being that neither the PASM -> SPASM not the PASM -> GT3 upgrades are really doable unless you have loads of $$$ and absolutely want OE parts. If you really want those options, you better order them from the factory.

Like I mentionned previously, I think I will stay on what I have for a little while to do some more trial and error. If I change anything, I will probably go with damptronics and GT3 Cup LCA and TA with some RSS steer / sway parts. They seem to be the overwhelming choice by people who, unlike me, actually know what they are talking about.

But I need to figure out if it is the guy or the car first (I suspect the former) and then come to grips with my motivations (performance vs aesthetics).

Cheers,

T.