Antisquat is a suspension setting that causes the rear of the car to lift on acceleration. This loads the tires and on a solid axle rear drive car, you get better forward bite. (on a touring car you just make the car loose.)
Do you think the better isolation of single tire suspension movements outweighs the additional unsprung mass?
Scott- Yes. I think this is the key to the advantage of the 3-link. Each tire is forced down from a bump much more effectively with that shock right near the wheel. This is especially true on an uneven bump (not full width).
The 3 link has better antisquat properties than the center pivot and it is fully adjustable. What you do to calculate it according to Carrol Smith is first find the virtual center of the 3 links much like you do with dual A-arm front suspensions. (see the diagram below). You then connect a line from the tire bottom to the virtual center. The higher this line the more antisquat. He gives antisquat a percentage number. The lines height at the center of mass divided by the height of the center of mass times 100. My car is set up with near 100% antisquat. Going higher does not seem to help and hurts cornering a little.
I had a 3 link antisquat video. I'll see if I can find some Web space to post it in a week or so.
Antisquat of three pan car types compared
The center pivot car has antisquat properties like you mentioned. I have driven three types now and can rate the antisquat. You can also calculate antisquat as the ratio of center pivot height to distance from axle to center pivot. What is different on these three types of cars is the distance from the axle to the pivot.
The Woods Racing T-plate car is actually a center pivot car as the rear of the T-plate does not flex up and down. There are three pivot balls on the leading edge of the pod to help the pod just pivot on the T-plate. It has the best antisquat and the best corner exit bite (even without the inerter) of all the stock pans that I tested. The reason is the pivot is as far back as possible. It is on the front edge of the pod.
Next the center pivot side link. Here the pivot is positioned at the back of the frame on a tab that leads the bottom front edge of the pod. Antisquat is still good.
Last is the standard T-plate car. Here it is said the pivot point is just forward of the back pivot ball on the frame. I think it is at the back pivot ball, but there is indeed flex in the T-plate in front of this ball. This car has the least antisquat.
Making a car with the pivot just under the motor shaft would give the car mad antisquat. On a wide pan car there is room to the side to do this. The pod would not rotate up so freely though from a bump as the distance from axle to pivot is now small. The suspension would act more solid I think. It is like having a front suspension with very short arms. It just does not work as well.
pic: left side schematic of a 3 link car. The green lines are the upper and lower links. This car has 70% antisquat dialed in.
Thanks for the posts guys.
I can send the short 3-link antisquat video by e-mail. Send a request to
[email protected] 757 kb
John