I have a question regarding setups and shock rates.
I guess the specific question is what rate are the in-game dampers representing? Are they static (one rate regardless of load)? Low load or high load?

I have a pretty good idea of how dampers work but from tests I have seen on dampers I'm am a bit confused at how LFS models dampers. Taking a look at a damper dynomometer of the model damper in my car there is data representing different loads and different rates which loads are applied.

The car I have used is the FXO because I can get pretty close to the same weight, weight distribution and power output as my 2001 VW Jetta. The FXO also has a McPherson strut front and a trailing arm rear suspension. The only specification I could not find is for the stock-sway bars but after some experimentation I found a combo that feels like my car with and without the aftermarket rear sway (which i have a good idea what the sprint-rate is) that compliments the stock bar. As far as dampers I can get the car to handle very similar to my car, but without the feel or a g-meter for in my car its hard to tell how close the rates really are. I also found it difficult to lift the inner-rear wheel under hard cornering on a flat surface in LFS.

The attached images are from a shock dynomometer using VW R32 stock Monroe and aftermarket Bilstein Sports. Which value would you use for the in-game settings?
I could not locate the results from the exact shocks on my VW Jetta, but with the 'sport' suspension with stiffer shocks they should be very similar if not the same as what is on the R32.

I'm no expert in this area, but from what I understand LFS dampers are linear. They are rated, obviously, in m/s. Your 20in/sec is going to be about .5 m/s. You'll have to figure out the conversion the imperial units to metric.

You'll have a lot of trouble matching up damping rates at various speeds because of the linear nature of LFS dampers. They are not progressive or speed sensitive. In other words, they give the same damping rate at any given speed. So instead of rising steeply for the first 2 to 5 in/s and then leveling off, the LFS dampers will just be a straight line if you had them on the same shaker rig as your car. So, you are best off picking a rate that matches pretty closely up to the first 5 in/s or so and going with that.

BTW, a 20in/s rate or a 1m/s rate is an extreme bump and not something you are likely to encounter unless you square up a curb.

Quote from Hallen :

I'm no expert in this area, but from what I understand LFS dampers are linear.

Correct.

Thats good to know. explains why in fast weight transfer maneuvers the car felt really over damped when at a slower weight transfer it was the opposite and vice versa. unfortunately I cannot use the shock dyno's i have and had in the past because there is little detail where i need it. in game i found a rebound rate of ~5-6Ns/mm feels about right but the dyno charts I have do not have enough detail that will line up to LFS. 5Ns/mm is 28 lb.s/in. but, its close enough for LFS to just throw in some numbers and drive around to see how it feels.

another question about damping in LFS, is any dampening from tires taken into account in any way?

Yes, the tyre spring effect is independently damped.

I think it is pretty critical that sooner, rather than later, LFS incorporates speed sensitivity (progressive rates) into the dampers. Again, I don't have a ton of experience here, but at least for production model cars, I think almost all dampers are going to be speed sensitive. I know the Bilsteins on my car are and every shock graph I have ever seen shows the same type of curve that yours shows. The linear rate is impossible to match up with a progressive rate damper across the normal spectrum.

Of course, it would also be very nice to have adjustable dampers for fast and slow bump too. But again, these have been covered in the suggestions threads.

I found all this out when trying to setup the XRG like my BMW E30 track car (thanks again Bob for the help with that). I got it close, but you can't really nail it because of the dampers. (BTW, with the upcoming changes with setup restrictions, it would really be nice to have the rebound setting back for the XRG. )

How much use would the fast end of the damper curve get used on a smooth racetrack? Not as much as your typical B-road surely?

Quote from Bob Smith :

How much use would the fast end of the damper curve get used on a smooth racetrack? Not as much as your typical B-road surely?

Crubs, braking zone ripples, pavement seams.

Yes, racetracks tend to be smoother than your typical local road, but only the newest ones (<2 years old) are largely without imperfections. The first road course in my state was just completed mid-2008 and it already has large patches of sealer in two corners. There is one chicane that is fairly bumpy about halfway between the last apex and exit, too.

Quote from Bob Smith :

How much use would the fast end of the damper curve get used on a smooth racetrack? Not as much as your typical B-road surely?

Not nearly as much as they would on something like, oh I don't know, a rallye car maybe?

But your point is correct. On a race track, especially the LFS tracks, you aren't going to find much in the way of paved surface bumps that would push a shock into the fast bump area. For a track where you are taking a lot of curb and the curb is fairly sharp, then yeah, you'll get into that range.

I would point out a track like Sebring, and just about any of the US street courses definitely would put you into the fast bump range. But that doesn't apply to LFS so the damper settings we have are OK for the majority of it. But it would be nice to have the progressive type dampers.

Rfactor has low/high speed damping, and MOTEC to log damper speeds. I made a mistake because when you look at a damper spec and how to integrate it into a car, you have to take the motion ratio into account..

For the actual damping, its a function of MotionRatio^2, but for the low/high speed transition, its just a function of MotionRatio, and it goes the other way!

In my case the MR was 1.5, the slow damping 6000 bump and 12000 rebound, with a loow/high transition point of about 0.14M/s

The values at the wheel are then
Bump = 6000 / 1.5^2 = 2667
Rebound = 1200 / 1.5^2 = 5333
low/high transition = 0.14 * 1.5 = 0.21 !

Quote from Hallen :

Not nearly as much as they would on something like, oh I don't know, a rallye car maybe?

But your point is correct. On a race track, especially the LFS tracks, you aren't going to find much in the way of paved surface bumps that would push a shock into the fast bump area. For a track where you are taking a lot of curb and the curb is fairly sharp, then yeah, you'll get into that range.

I would point out a track like Sebring, and just about any of the US street courses definitely would put you into the fast bump range. But that doesn't apply to LFS so the damper settings we have are OK for the majority of it. But it would be nice to have the progressive type dampers.

South city. In a few places. Railway lines especially. I'd really like to see more tarmac rally type stages in LFS point to point *dribble* with some true road conditions (potholes, bad tarmac edges, gutters etc) But at the moment, south city is about the only track i can think of with some nasty bumps..actually..one of the aston tracks has that nasty bump right on the apex, left hander up towards the start line, just after you come down the "S" hill. So, there is a few places at the moment that could benefit from it.