rear shock setting

[Bill Harris]

Hey, no disrepect taken! I'm no suspension expert. I just decribed the operation of a leaf spring setup as I understand it from experience and a little physics. I'm not sure how the shock settings affect a four-link style suspension. A four link is a much more complicated (and sophisticated) suspension than a leaf spring. The fact that there are upper and lower control arms that are transferring the energy to the chassis in a push/pull manner is a completely different process than a leaf spring. It may very well be that the shock setting affects the launch differently with that geometry than the leaf spring.

I like Myron's analogy and his experience is the same as mine with leaf springs and traction bars. I always soften my shock settings on loose tracks and tighten them on tracks with good bite and the car responds accordingly. My analysis seems to explain the action from an simplistic energy perspective. If the car is doing anything other than moving forward, then energy has to be going somewhere other than to the tires. The greater the motion in a direction other than forward, and the longer that motion takes place, the less energy is being applied to the tire/track interface.

I'll have to pay attention to the four-link style suspended cars on launch to educate myself. Do they have a tendency is to squat on launch?

[Todd Geisler]

Originally Posted by Bill Harris

Hey, no disrepect taken! I'm no suspension expert. I just decribed the operation of a leaf spring setup as I understand it from experience and a little physics. I'm not sure how the shock settings affect a four-link style suspension. A four link is a much more complicated (and sophisticated) suspension than a leaf spring. The fact that there are upper and lower control arms that are transferring the energy to the chassis in a push/pull manner is a completely different process than a leaf spring. It may very well be that the shock setting affects the launch differently with that geometry than the leaf spring.

I like Myron's analogy and his experience is the same as mine with leaf springs and traction bars. I always soften my shock settings on loose tracks and tighten them on tracks with good bite and the car responds accordingly. My analysis seems to explain the action from an simplistic energy perspective. If the car is doing anything other than moving forward, then energy has to be going somewhere other than to the tires. The greater the motion in a direction other than forward, and the longer that motion takes place, the less energy is being applied to the tire/track interface.

I'll have to pay attention to the four-link style suspended cars on launch to educate myself. Do they have a tendency is to squat on launch?

With the stock style GM triangulated 4 link suspension, it depends on how the suspension is setup to whether it separates or squats. In stock form the angle of the bars have negative anti-squat which means they squat in the rear when power is applied and this essentially pulls the tire up in the chassis reducing loading on the tire. My car has the upper bar angles altered to change the instant center length & height which also alters the anti-squat values to around 115% which creates a moderate separation, but not near as violent as say the old style Southside Machine bars were (around 175% A/S as I remember).

Apparently we cannot compare hit to the tire between leaf and coil spring style suspensions. I understand the coil spring stuff fairly well, but never had the opportunity to work with tuning a leaf spring car.

[JOE B]

i will give a little input on to what my trouble has been . both foot braking and trans braking launch it seams that the car goes allmost straight up with a lot of body separation. its does have full frontend travel .

a link to some launch photos.
http://www.gallery.smithspeed.com/th...s.php?album=22

its the orange pinto .