matching dampers to spring rates

[graveltrap]

How do you do it.

I've got a few ideas.

1. The dampers are magically matched to the spring rates when they are changed (every car i've looked at always comes with the dampers set at 7,7) you can then tweak the dampers to suit your driving style.

2. with full racing suspension you may adjust the spring rate from 4.0kg/mm to 20kg/mm. There are ten avaliable settings for dampers. Therefore every increse in spring rate by 1.6kg/mm would require a change in damper settings of 1.
this would be a rough benchmark and then the dampers could be tweaked to suit.

Table

4.0-5.6=1
5.6-7.2=2
7.2 -8.8=3
8.8-10.4=4
10.4-12=5
12-13.6=6
13.6-15.2=7
15.2-16.8=8
16.8-18.4=9
18.4-20.0=10

example, Mugen S2000 SR F 7.0kg/mm initial damper setting 2 SR R 11.0kg/mm initial damper setting 5

3. you have to tune the dampers by feel. Set bound and rebound to zero. Starting with the bound increase by 1 click until the car starts to looses grip or starts to skate at one end. Go one click back at the end that is skating and carry on increasing the bound at the other end until the same thing happens i. Then tune the rebound in the same manner until the luxury feel is gone. You can then adjust the dampers for improved handling. This is a really long method of getting damper settings correct.

4. Guess

 

[///M-Spec]

Good stuff, graveltrap. A combination of method 2 and 3 should yield the best results, and is my prefered method.

In real life, matching shocks to springs is a complicated process that takes time, patience and more than a passing understanding of suspension tuning. This is why the best aftermarket kits are sold as matched sets --saving you the research for proper valving for your spring rates and your car.

Luckily, all the cars in GT3 have linear, rather than progressive rate springs and shocks. In addition, all you want is the most performance oriented setting --not an ideal balance between ride and grip. This makes matching them much easier.


THE DRIVE WHEELS
I usually start by working on the drive wheels --the ones putting the power to the ground --since they are the most important ones. (AWD cars I always start with the rear wheels)

I'll make the car as low and the springs as stiff as possible for the track until the car becomes jittery over the rumblestrips (or the apron), then I'll back up a tick or two. This usually results in a pretty stiff car.

Using the min/max spring ratio as a guideline, --I like your chart, gravel --I'll guesstimate a place to start.

I'll experiment by hitting a rumblestrip at speed and full throttle:

If the car bounces from the inital impact and loses traction, I REDUCE the spring rate a little and I reduce BOUND (compress), until it goes over the rumblestrip without much drama.

If the car is fine over the inital impact, but occilates, jitters or skips after it hits the strip, then I leave the spring rate alone, but INCREASE REBOUND (uncompress) until the behavior stops.

The goal is to make sure that the roughest spots on the track (usually the rumblestrips that you need to hit in order to drive the fastest line) do NOT interupt you from putting down power --or worse yet --yaw the car, making you spend time correcting (unless you WANT this to happen)

*Keep in mind that sway bar settings will affect your stability over bumps if they are set too hard/high. If your car is still bouncing too much, reduce your sway bar stiffness.

*Also, in a RWD or some AWD cars, sometimes having your rear springs or sways set too high/stiff will cause the car to have BIG power on over-steer. If you find your car is too loose, you should probably reduce REAR spring rates a little, since too much oversteer wastes valuable horsepower.

CAR BALANCE
After the drive wheels are set up, I'll fine tune the car balance to suit the course and my driving style. I personally prefer to have the car push a little at corner entry, then be neutral under power with a hint of oversteer.

If anyone is interested, I'll post some guidelines for obtaining car balance by playing with spring/shock/sway bar/camber.

So in the end, you should have a car that can put down power as early as possible, and has good enough balance for you to do your job.

I should point out that I drive all my cars with traction and stability control OFF, since these devices always hide handling deficiencies.


///M-Spec

 

[graveltrap]

Interesting M-spec, I've got a damper tuning guide written by a Cart crew chief somewhere, I'll post up the table from that when I find it........

 

[graveltrap]

Shock tuning for handling table/ artical

http://www.smithees-racetech.com.au/theory/shocktune1.html

 

[graveltrap]

I forgot to say I'm interested in the guidelines for obtaining car balance by adjusting springs, dampers, anti roll bar, camber......think that would require a new thread

 

[///M-Spec]

Graveltrap, thanks for sharing the link. That was a good read.

I'll post a table on balancing a car with suspension tuning in the next day or so. Things are crazy at work and I can't sit and type for more than a few minutes at a time before some fool calls me with a problem...


///M-Spec