Stock and Bilstein Coilover damper and spring rates

[TME_Steve]

Hi all,

Before embarking on my suspension changes journey I though it best to find out exactly what was in there first. I couldn't find definitve information on this so with the help of M0R81U5 (tested his old suspension) I was able to measure stuff without taking my car off the road.

So these results are for a PFL Legnum.

Front Springs: 3.75kg/mm
Rear Springs: 2.85kg/mm

Front damper dyno graph:

Rear damper dyno graph:

So if you're like me and love spreadsheets to calculate everything in life these may be of assistance, can't guarentee this is what they were like factory as they are 13 or 14 year old components but it does represent what a stock PFL would feel like now. I have no idea if PFL to FL has a different level of damping or spring rates either.

 

[VOLK]

Outstanding. I do enjoy a good graphical representation.

 

[M0R81U5]

Nicely done Steve, as always

 

[TME_Steve]

OK so now I have some Bilstein coilovers to go in but before I do, best check what they are and if i want to change them.... interesting results, front dampers much the same on bump and about 30% more rebound. Rear dampers less bump at high velocity and about 200% more rebound.

So springs? Front = 14kg Rear = 8kg thats 370% front stiffness and 280% more rear. (No they will not be going in my car like this (well not for long anyway).

Oh and can a mod please change the title to say "Stock and Bilstein Coilover damper and spring rates"

Front Damper Graph:

Rear Damper Graph:

 

[jungle]

Its a deceptive graph Steve as first glance. I needed to look again for the scale. Although the shape is similar the scale is different.
Still springs are cheap compared to dampers, put in what they reckon, i'd go softest first front and rear and see how they go?

 

[TME_Steve]

Ooh, only just saw your reply, better late than never....

Yeah, a bit more overall rebound, especially in the rear and lot more initial rebound in both. Bump is similar, in fact maybe a bit less in the rear now and you can see that they're almost zero and no movement now as opposed to negative bump in th factory ones with zero movement, I guess that's a bit of wear in the factory dampers. I'd love to spend a lot more time on this but suspension is just too damned expensive. I can get the Bilsteins made independently adjustable for bump and rebound which would be nice but I don't want to pay for it.

 

[jungle]

Ooh, only just saw your reply, better late than never....
I can get the Bilsteins made independently adjustable for bump and rebound which would be nice but I don't want to pay for it.

Yep, I'm hearing you loud and clear. Trying to line up some JRZ but its proving difficult and expensive.