Lex_GTX

We have a 997.2TT development vehicle and we focus on engine tuning. Our 997 started to have the rear PASM shocks leak so we purchased a KW V3 suspension.
The car is tuned for more power and sees a good amount of autox and track use.
At the same time it is used as a daily for development - we must use it in as many conditions as possible.

I enjoy the suspension in sport/sport+ in autox and the majority of driving. It is a bit stiff and skips across quick road undulations - so finer dampening would be welcomed. Normal mode does not feel stable enough and too soft.

I want to setup the KW suspension correctly from the get go for the intended use for the car. I want it to feel stable at high speeds and continue being very competitive at autox. I heard the front springs that come included with the kit are too soft. From those who have set this suspension up and ran it on the road as well as in a competitive manner - what are your recommendations?

Thank you in advance!

Lex_GTX

Let me rephrase the question - those running the KW V3 (non lift) coilovers, how do you find the included springs?

gsxrjjordan

Do you know what the included spring rates are on your V3's?
Ohlins comes with 343/686 per my notes, whereas Bilstein B16 comforts come with 255/515 reportedly, so there's quite a range of what's "good" for our application.
For a full-weight street car that sees track time (and especially if you enjoy driving it in PASM Sport, which is pretty stiff) I'd guess you'd be happy at the stiff end of the range.
Tom @ DSC/TPC recommended 350/650 or 400/650 for B16's, but I don't know what the KW's are valved like in relation.

Lex_GTX

I am trying to get this information from KW, I have found conflicting rates posted.

I do prefer the sport mode on the OEM suspension and since this car is used in autox, I prefer it is on the competitive side of the spectrum. When speaking with KW about V3 versus Clubsport (which use similar shocks) they recommended the V3 for me. There is once again conflicting information. I have run many KW kits on different cars and on some the springs are spot on for a sporty autox worthy application while on others I find a touch soft.

ShatterPoints

KW has linear fronts and progressive rears. I found that they are ~216lbs front and 742 rear. IMO the rear is really high and the front is more or less fair.

Lex_GTX

To me it looks like the fronts are progressive and rears linear. This is an actual image of the kit.

ShatterPoints

You can call KW if you'd like they will tell you linear front and progressive rear. They will give you the front spring rates but not the rears. People have measured the rear springs and counted coil activation to come up with the number I gave you. I am not sure what the spring rate is at different moments of travel.

Lex_GTX

Spoke with KW.

The V3 has the following rates:

Front: progressive 220 lb/in
Rear: linear: 740 lb/in

Clubsports:

Front: linear: 400 lb/in
Rear: linear: 970 lb/in

ShatterPoints

I'm jealous of you. I have tried more than once to get info from them and was always told they couldnt give rear spring rates. Thanks for setting the record straight.

Edit* at ~250lbs the front ride rate is 1.9hz and at ~550lbs the rear ride rate is ~ 2.3hz. The rears are right on the very edge of too high without some aero in both options IMO. The fronts for the non clubsports are actually a little low if you want to track the car, and the clubsport fronts are a little high IMO.

Lex_GTX

Thanks for the insight. Did you have a table made where you calculated the rates and frequency difference? Reason I am asking is I am interested in the input variables (weight per axle, speed).

I was considering the swift 280 lb/in springs up front as a better compromise for a dual purpose car versus the included progressive springs.

ShatterPoints

Matter of fact I do have a spread sheet. I will be able to make it available to the forum. It was created through collaboration with the indie shop I got my work done at. I will post mine and then a blank one for everyone to use.

gsxrjjordan

Sweet!

Lex_GTX

Giving this thread another bump. I am considering replacing the 220 progressive front springs included with the kit with a set of 280 lb/in. From those having installed these coilovers, do you happen to have measured how much the front springs are compressed once installed? Since they are progressive it is hard to determine how long the swift replacement springs should be.

ShatterPoints

Working on getting the spread sheet for you. It was part of some collaboration from the tuner I went with to re valve my suspension. He will make the blank one available soon. I will see if I can release any of my info to you.