Hindsight2010

I recently installed a set of new Ohlins Road and Track coilovers on my 997.2 C2S (which previously had working PASM). I thought I was going to track the car more than I will likely be able to due to time constraints and family stuff, and I have found the Ohlins to be way too firm for street use for me personally. That shocked me because I had ridden in other non P-cars with Ohlins R&T coilovers and I found them to have a better ride than OEM and do a great job of soaking up the big bumps without being harsh. But on the 997, it's just too harsh and jarring, regardless of strut adjustment setting. I believe this is mostly due to the very high spring rates the Ohlins utilize.

Ohlins have 343F and 686R
OEM C2S is 188F 320R

So Ohlins are about DOUBLE OEM. I didn't personally feel that my stock suspension suffered from extreme roll or dive so I see no reason for jacking the spring rates up so much.

Given that strut compression valving is mostly a function of unsprung weight, and rebound is more about the spring rates, and the fact that the rebound is widely adjustable on these struts, I am considering just getting different springs. Spring rates are highly subjective and personal - what feels good to one person might not feel good to another (obviously, since a lot of people like the R&Ts on the street but I don't). But I figured I'd ask the forum what spring rates you are running for a car you drive semi-regularly on the street, and that you find to be comfortable. As of right now, I'm considering going with 250/425, which would be a 33% increase over stock.

Thanks in advance!

RacerWannabe

Does anyone know what the spring rate is for the Bilstein B16 Damptronics? Whatever that is seems good to me.

Hindsight2010

All I could find is for the 997.1 turbo, and those are 340/565.

RacerWannabe

Wow - ok - higher than I imagined them to be. I suppose then that slightly lower spring rates would be nice for a more compliant ride. I DD my car in NY/NJ so the roads are awful...maybe I'm just used to a stiffly sprung car. It could be a little more compliant I suppose.

Aclmin

The 997.2 GT3 coilovers that I swapped in are factory 270/620 and while the ride is firm it’s not harsh.

Hindsight2010

I've noticed that the GT cars have a larger difference in rate between front and rear and generally that is due to them having aero. The more aero, the more spring rate.

ejabour

Good point. It also changes the balance of the car and dials out some of the understeer.

andino

The larger spring rate differences in GT cars also maintain a higher flat ride ratio. Even our stock springs have around 10-12% flat ride. Most aftermarkets tend to go for a lower ratio or even into pitch to make the car feel "sportier". The 997.2 GT3 RS for example has around a 20% flat ride IIRC. That helps the car settle really quickly over bumps and curbs.

PJP13

My MCS 3 ways are running 600/800 on my .2 GTS. While it may be too firm fir daily driving, I actually find it more enjoyable and responsive than the factory SPASM.. for a weekend car that does track time it feels like a really good balance to me.

Hindsight2010

That's exactly how I thought the Ohlins would be but the roads in Atlanta are awful and the Ohlins spring rates are stiff enough to make driving the car simply not enjoyable. I bought this care only as a toy so I don't want to remove from the driving pleasure. Especially considering I won't be able to track it as often as I thought I would.

Tj40

If it helps there is a spreadsheet in this thread with all the data I could find - including coilover rates - data is all cribbed off the internet or manufacturers sites - I might have a updated version on my other PC if this is useful

https://rennlist.com/forums/997-foru...e-roundup.html

I have far too much time in the winter when it snows up here.......

Petza914

I'm running whatever my B16 Damptronics came with for my C2S, which is the Sport version. For the RWD cars they only make one version (Sport). For the AWD cars they make both a Sport and a Comfort version and the difference between them is the Spring Rate according to Rhonda at FVD. What those actual values are, I don't know.

I would have recommended you do the Damptronics to preserve the PASM capability - who knows, maybe I even did. Utilizing those and adding to them the TPC DSC module is a perfect combination.

Before you spend more money and make changes, if you want a ride in my supercharged 997 with the RSS Stage 2 Tarmac suspension bits, Bilstein B16s, and TPC DSC box with custom profile maps, I'm only a couple hours away from Atlanta up in Clemson. Let me know. Alternatively, now that the car is back on the road, it may be the one I take to Petit le Mans at Road Atlanta on Friday or Saturday (or both) if you're planning to attend this year. My son and I will be there both days if the weather is good and we could run up the road for a bit.

I installed the B16s and all the RSS stuff together, but it was before I added the DSC. The Damptronics worked much better than the OEM PASM suspension and I only had 35 or 40k miles on my PASM shocks, so they weren't tired yet. It's the rebound dampening I find to be lacking in the stock PASM setup, that and that the Normal & Sport profiles from the factory aren't all that great.

Hindsight2010

I wasn't planning on going to the petit this year, though I did go last year. But I could meet you out there before or after it for breakfast or dinner or coffee or something if you have time and bring the car. Otherwise a leaf-watching road trip out to Clemson might be in my immediate future. Would love to check out your setup and compare notes. Let me know when you decide if you will bring the car to Petit!

Petza914

OK, will do. Need to do about 60 more miles before I can do an oil change and get the regular oil in there. This weekend looks like rain for F, Sa, & Su, so may not know until Wednesday or Thursday of next week which day or days I'll be taking the car, but probably one of them. Based on the itinerary, we could likely meet up for lunch on Saturday a bit after the race starts - maybe around 1:30 or 2. There's the Cracker Barrel at the Road Atlanta exit or an Italian Restaurant a bit further up the road on the way to the track, and some other stuff too. I'll shoot you a PM with my cell #.

KJR50

F550/R600 on JRZ 2way adjustable, definitely rides better than OEM. Check your alignment and tire pressure.