KJR50

I’m confused. Are the Ohlins pasm-capable shocks? How does adding a DSC help?

jondrayton

Hi,

I also have Ohlins and have been considering changing the springs. As I understand it there are softer spring options available from Ohlins. I read a post a while ago on the 911uk forum where the springs were changed for a softer setup. I think they were “mid” springs. I haven’t looked into it personally but I guess an enquiry to Ohlins would reveal all.

Cheers

Jon

Hindsight2010

Both are spot on. Had it aligned yesterday in fact.

Hindsight2010

Ohlins are not PASM capable but the B16 Bilsteins that @Petza914 referenced are. So he has the PASM compatible B16s with the aftermarket TPC DSC controller.

Hindsight2010

The springs on the Ohlins are not proprietary. They are a very standard 2.5" x 8" spring used in many coilovers from many manufacturers. You can but them nearly anywhere, but summitracing.com has the best search feature I've been able to find. You can find them in 25lb increments. $65 each for springs made by Eibach (a well-known and trusted brand).

I've tried to contact Ohlins to double check that I won't need to send the struts in for re-valving with softer springs but I have been unable to reach them by phone or e-mail unfortunately. A friend who I trust tells me the adjustability range of the Ohlins is enough that I won't need different valving.

Current plan is to go with springs that are about 30% stiffer than OEM, instead of 100% stiffer which the Ohlins came with. I hear people complain about body roll in the 997 but that was not my experience. I found the car to be pretty flat, even on the track. So I think stiffening it up a tad with a 30% bump in spring rates plus the GT3 sway bars I added should be the sweet spot. I'm also considering a 50% bump too but I just really don't want it to be too harsh. It takes a good while to swap springs out on these cars, and ~$350 per set of springs, plus an alignment, so I would really prefer to do it once and be done with it.

1990nein

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Hindsight2010

Yeah I called and left a voicemail. Haven't received a callback. I did get ahold of Performance Shock Inc, who is a big Ohlins dealer. They told me you can change the spring rates up to 25% before needing a re-valving.

Sway bars are OEM GT3 (my car is a 997.2 CS2). Tires are brand new Pilot Sport 4S and pressure is 37F 44R. Also have a set of brand new Pilot Sport Cup 2s I run with.

Hans2016

I switched from the 340/680 lbs Oehlins rates to Eibach springs with 275/550 lbs rates. The car is my daily and much more comfortable.

1990nein

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jamesinger

^^^ going from the door sticker cold pressures on my C2S to 29/33 GT3 psi on my PS4S made a BIG difference.
my spring rates are OEM 997.1 GT3 and with the PASM that is more chill than other coilovers I have had.

EDIT: I just wanted to add that I am running GT3 wheels but things have changed since the door sticker for our cars was made. The pressures on your door sticker and the pressures for some tire that didn't exist when our cars was made is probably different.

Hans2016

Can you adjust the tire sensor to the lower tire pressures?

Hindsight2010

Thanks for the replies guys. I'll try running lighter tire pressures though I am skeptical as to how much of a difference it will make. It's easy to try though so I'll give it a shot.

Regarding sway bars, yes I'm definitely aware of how they impact ride (and also handling characteristics). They will always make uneven bumps more jarring, but even when I hit a bump that hits both tires the same, its just too stiff for my liking which is a spring rate and or damper thing.

Great to know @Hans2016 ! That's what I was looking for. Are you very happy with the ride after that spring change or do you find yourself wishing for even softer? Was the change really very noticeable? What damper settings are you running (how many clicks from fully firm)? And no, to my knowledge you can't adjust tire pressure sensor calibration - all you can do is completely disable the TPMS system from the car using a Durametric Pro or the tool the Porsche dealer uses. Sadly, none of the FoxPro tools will allow you to disable TPMS.

jamesinger

I posted this in another thread but your thread got me thinking and the PS4S are not N0 tires from Porsche. They are not N1 or etc. for our cars either. Please correct me if I am wrong but it seems like the main N0 tire for the Carreras is the PSCs (N2) and for the GT3 is the PSC2s (N0), which is not really a daily driver tire unless your daily drive is real aggressive and you track on the weekends. Also, these tires probably have a much stiffer sidewall than even something like the PS4S. I am using Tire Rack as a reference point, so that might be flawed (and please correct me if it is) but it looks like for both the lobsters and the GT3 wheels I am running, the only N0 tires are PSC2s for the GT3 wheels and the PSCs for the lobsters are N2. The point is, whatever PSI is on your door card seems somewhat irrelevant in relation to the evolution of tires over the past 14 years (for me). My car had the original tires on the car when I got it in 2018. From my memory, they were the old Pilot Sports but that was 2 years ago and they were only on the car long enough for me to drive to a tire shop that had PS4S waiting for me. If I was tracking over 3 or so full weekends a year, I would be running PSC2s for sure.

Regardless of tires, I had the KW Clubsports on 2 EVO VIIIs. Bear with me because it is relevant IMO. I would go as far to say that out of the box, the KWs sucked. I put them on. I did an eyeball alignment with a guy who knew what he was doing. It was decent but I was bummed at the result going from Bilestein shocks and Swift springs to the higher end KW Clubsports. I took the suspension to a suspension Guru about a month or so later. Here is where things get weird. He revalved the shocks and swapped out the springs to his "spec." I also got all solid bushings and some extra chassis bracing at the time. After an alignment and corner balance, the car was amazing ...for tracking. At the time I had a young back and a second car I could daily, so I was super happy with it.

However, at some point, I got massively rear ended on the highway. A year later, after another almost head on crash where I swerved just enough to get t-boned by a wrong way driver (yay Los Angeles driving!!), I was down to just an EVO and chronic injuries from Mad Max Los Angeles Edition driving (side note: I have been hit while sitting stationary in traffic 6 times in 20 years of sitting in traffic in LA. IDK if that is lucky or unlucky. My back feels like it is unlucky). ...In any case, I went to another suspension Guru and explained my dilemma. This was after a few thousand daily miles and many time attack events on the previous set up. He revalved the shocks again and changed out the springs. He also changed all the hard bushings to poly bushings (with some other details...). He aligned and corner balanced the car. This ended up taking 2 trips for some adjustments over a few months while I drove the car. For example, the first trip, I did not change out the suspension arms and bushings in the car. I got it back after a couple tries though and it was BUTTER. It was so perfect for daily driving I would take my mom to dinner in it. At the tracks around here, it was oddly faster but it is hard to quantify because the car was constantly evolving in multiple ways and I never got to track the set up myself because of my neck and back not wanting to do that anymore, so the driver was a guy I had tracked with extensively and was about the same experience and skill level as me but that is a weird variable, so whatever.

NOW (TL;DR) what is my point?

In the right hands I know Ohlins can be super smooth. I have driven and ridden in multiple EVOs with Ohlins where they are so buttery it made me want Ohlins super bad. ...but ALL of those cars were 100% set up by a suspension expert and I am pretty sure none of them were running the springs that came in the box. Revalving your shocks is probably overkill but I would start with a solid alignment and corner balance. Tell the suspension tuner the truth about how the car will really be driven. Let them do the clicks and the set up. Don't touch it and see how it is (i.e. I have a friend who got his suspension done and wasn't happy with the stance, so he lowered his car immediately negating whatever benefit he got from careful corner balancing and etc.). If you are like me, you have a tendency to overstate your aggressive driving whereas, in reality, if the car is a daily, I drive it 90% or more in LA traffic and 10% in canyons or on the track. If that is still not where you want it, consider lower rate springs and a proper set up again. After all that, if you are still unhappy, it won't totally be overkill to revalve because it might be getting around that time to rebuild regardless depending on how much you are tracking.

I didn't want to post this super long post at first but as the conversation went on, I felt it is more and more relevant because I really felt the same about my KW Clubsports at first. Driving them in daily conditions was a bummer. Even just driving to and from the track was a bummer too IMO. At the track, they worked great but were super harsh. I do not think you need to get your shocks revalved but the whole point of high end coilovers like the KWs or your Ohlins is that you can dial them in exactly how you want them and for their intended purpose with some work. Suspension is the main thing I get really obsessive over, so sorry for the long post but I think about it a lot.

Hindsight2010

I too have ridden in several non P-cars with Ohlins that were super smooth (Audi and FRZ if I recall correctly). But my car has already been corner balanced (by me) and had a solid alignment to specs I had researched here and other places for quite a while. I generally do all my own work and my own setup, and have done so for years because I don't trust people to work on my car. I got lazy this last week and took my car to a reputable shop for an alignment, and also to have the swedged tube for my front drop links swapped out with shorter ones because the ones that came from SPL were too long and almost didn't clear the LCAs. I got the car back with a nasty scratch in the leather on the steering wheel and the lock-nuts for the swedged tube were sitting 1/8" away from them (they weren't locking the adjustment). Prior to that I had not taken a car to a mechanic for ages and this just reinforced my previous lessons. You want it done right, you do it yourself.

I have 2 sets of wheels and tires..... The PS4s are on there now, but I have a set of new Sport Cup 2 N0s on the OEM wheels that I run on the track. I will have to put those on the car and see if there is any difference in ride.

I lowered the air pressure to 29/33 cold in the PS4s today and I will admit that it took some of the edge off, but I still want to go to softer springs - still too harsh. Since Ohlins says you can change up to 25% spring rate before needing a revalve, I will likely go with ~250/500 springs.

jamesinger

I agree about working on your own car. That sucks about your experience. I just had one similar to that as well in September. I try to work on my own car when I can.

In any case, it seems like doing the springs is the next logical step. Sorry for my long winded replies.

One last question, do your Ohlins have helper springs? One thing I noticed was when I gentled down my KWs, even though I had already previously resprung them, the best set up I had were longer single springs rather than shorter springs with helper springs. The last guy who redid everything changed from some eibach ers + KW frankenstein situation that worked to a better more street friendly Swift longer single springs situation. ...but like I said, suspension is kind of a dark art to me, so I do not know all the little details of that. It did make a massive difference.