Better suspension setup 997.2 C2S
 

Hello everyone! Looking at my next set of mods. Was thinking about GT3 LCAs to be able to dial in some more negative camber for better track performance. What would you do in conjunction with this and what else would you look at? What about sway bars and rear suspension?

one issue I’m having is finding someone here in town that can do a track alignment, so I don’t want to spend the $$$ for the upgrades if some shop just aligns me to stock specs. Any guidance would be appreciated.

The Porsche dealership I go to for things I dont want to do myself took the printout I gave them with the specs I wanted and did the alignment on my car. Worth a shot if you dont get something better.

Is there somewhere that would list some specs to take? Thx

Tell them to use GT3 specs.

Start with an alignment shooting for GT3 specs. On a stock C2S front camber will come up short at around -1.1. GT3 specs are -1.5.
Next get the DSC box to replace the OEM PASM controller.
Semi solid engine mounts help reduce the rear end pendulum effect.

After these are done then start thinking about more up front camber to get to -1.5 camber, coilovers, and corner balancing. Then if more is needed look to sway bars with adjustable drop links, and replacing rubber components with monoballs.

Stock GT3 street settings are not enough for a tracked vehicle. They are still set to understeer safely and run heavy toe settings, just as with any modern Porsche.
I would install the GT3 front control arms, making sure to install the trailing arm to lower control arm bolt in the second caster setting, and then have them add shims to reach around -2.5 deg up front, 0 toe or slight toe, and the rear to -1.8 to -2.0 deg and 0.12 total toe.
This will not cause any dramatic tire wear, and will dramatically change the handling characteristics of the car in general. From there, adjustable away bars can help fine tune, but a decent set of shocks/coilovers will always give you more flexibility and gains in the end.

TL;DR, I know...

I think suspension is really the only thing I would try to get perfect in my C2S. I don't feel like you can really get such huge gains with other mods. If I wanted way more power, or a different transmission completely, I would just take out a way bigger loan and get a GT3.

Also, every car I have owned since I got my license has gotten progressively more suspension work done from cutting coils and removing leaf springs when I was a teenager in the mid 90s to completely reengineering all of the suspension components in a couple cars. I am not a suspension expert but I have thought about the suspension on the 997 C2S a lot. Also, I have some friends with both 997.1 and 997.2 GT3s. I notice suspension has been the #1 thing that makes me happy/unhappy with the cars I own over the last 25 or so years.

I got my car at the start of Feb. last year. Immediately I was surprised how high even the PASM C2S with sport chrono and etc. was. I was also fairly surprised at how much the car leaned in hard cornering as well as how much the car dove and squatted under hard braking and acceleration in both Normal and Sport mode. The first thing I decided to do was get new PS4S tires with 305s in the rear, Eibach Pro Kit Springs + some 15mm spacers to push the wheels out a bit. This helped a lot but it did not make the car much flatter in corners. The car would also dive and squat under braking and acceleration but less. I drove like this for about 6 months.

Around this same time, I read about how Tom at TPC had put GT3 suspension in his C2S that he was driving before he got his GT3. I researched the conversion and found it was cost effective and not too difficult. I also like PASM. It seemed like the cheapest way to retain PASM and have proper coilovers would be to source GT3 coilovers and refresh them. I have had multiple cars on manually adjustable non-active coilovers, so I welcome adaptable suspension after being on both sides of the streetable/trackable divide but always compromising. I think even the OEM PASM works really well too. I do feel like in the 997.1 C2S, sport mode is mostly useless except on a smooth track, which I would argue we do not have here in so. cal. (i.e. BRP, WSIR, and Streets all have quite a bit of bumps and etc.). I also felt that the difference between Normal and Sport in the C2S was way bigger than the GT3. I can hardly tell the difference between Normal and Sport mode in both the 997.1 and .2 GT3s I have driven. The overlap is much higher between the 2 modes until you start going much faster than I would on a public road, especially in the canyons, or unless you are creeping along in stop and go traffic. So, the main amenable difference I saw between my C2S and the 997 GT3s I have access to is suspension. Suspension was also the main thing I found unsatisfying about the 997 C2S.

As a result, I started to source some parts that could make it so I am essentially running GT3 spec wheels and GT3 suspension on a C2S. I ended up getting used GT3 coilovers + Eibach's Anti Roll kit (F+R swaybars and F+R adjustable endlinks). The coilovers took a bit of legwork to get the parts that you need to mate the GT3 suspension to a C2S but most of it was done by @EG997C2 on here (who might chime in because he has done GT3RS suspension on his red 997.2). The main things I needed were sleeves and extension cables for the front coilovers . The sleeves were from Ohlins, who I believe stopped making/selling them but you can still get these from Tom at TPC. The cables were from Bilstein. I ended up having to get my Bilstein cables through Summit because Bilstein does not sell them direct to end users (at least that day, they seem very inconsistent with their info). You also need some upper mounting bits as discussed here:
https://rennlist.com/forums/997-foru...nto-a-c2s.html

After assembling all the parts, I had Glenn Yee disassemble, assess, and report on the coilovers. Once I got them back I took the report to PRO Motorsports in Burbank to have Tyson Schmidt install and dial in the set up with an alignment and corner balance. I have gotten to drive the car as a daily since and I drove as far up Angeles Crest Highway as they will let you right now twice. I have also driven the same road in a .1 and a .2 GT3 as well as in my own C2S stock and with Eibach pro kit springs. At this point, I feel like the car handles like a GT3 completely. I want to do back to back comparisons on the same day just for fun to see but in the canyons and on the streets in normal driving, I feel like I have created a set up that gets rid of the only weak point in the C2S that really bothered me. I actually like my heavy 18 way seats and the leather dash/dentist spec/Bose system stuff after having no-frills EVOs and an all-frills prestige package Audi. What I wasn't OK with was the less than stellar suspension coming from a background of dialed in Japanese Imports and one stock Audi B8 Avant. I have also done way more suspension re-dos on my other cars than I would care to admit.

Last, the main thing both Tyson Schmidt and Glenn Yee both told me is that to round out my suspension for tracking specifically, the adjustable GT3 LCAs would be the next step. I think I will add the TPC DSC box first, since I only get to the track 6 weekends a year at best, and then I will look into adjustable LCAs and etc. However, after doing all this, if I could go back in time, what I would do is this (step by step first to last):
1. DSC box, for your car it is just plug and play. Literally, you just get it, unplug the PASM box and plug in the DSC box. It is easier than changing your oil or brake pads for sure, and cleaner!
2. Swaybars and Adjustable Endlinks (TPC says that with just 1+2, your car will handle better than much more highly modded Carreras, and I believe them).
3. Either GT3 coilovers or Coilovers that use PASM (i.e. Damptronics, Tractive...)
4. Adjustable LCAs...
5. I guess at this point, all hard everything but I have gone down this route before and I am avoiding it at this point.

Here is how my car looks now if that matters. BTW, I always tell suspension tuners to not ask me about ride height because I am an idiot and will just slam anything as low as possible, so this is just set at what Tyson at PRO Motorsports felt was optimal. Parked right now:
https://cimg5.ibsrv.net/gimg/rennlis...786700a91.jpeg

Thanks so much! This is exactly the things I was looking for. As a follow up, have y’all customized any of the dsc settings?

I basically did this, but first I added new rims with less offset to widen the track and improve turn-in. I also felt the car worked a lot better on Michelins than the stock fitment Pirelli P Zeros. The TPC Racing DSC controller really is a magic box to get the best out of your active suspension, so I have no plans to switch to coilovers. It is such a big step up in adding roll resistance, anti-squat and anti-dive, and – along with the RSS engine mounts - it really improves the body control: almost completely eliminating the front end float and ‘porpoising’. I then added H&R lowering springs because – as james said^ - I’m also an idiot, and I want to lower the car to take out some of the wheel gap. I did see that the realignment (I got -1.2 at the front) pulls the top of the front wheels in a fair bit.

As to next steps, I’m adding the Function First poly bushes to the gearbox mount, and considering adjustable front top mounts from Vorshlag for the front camber. I don’t feel the need for stiffer roll bars at this point, but adjustable drop links would probably be a good idea to help remove any pre-load. I mostly use the car on the road, and only get the chance to track it three or maybe four times a year (we have a short season).

^^^ Semi Solid Engine mounts are definitely on my list. Sounds like a solid setup!!