8 Bite Off the Corners

In situations where the exit portion of the track provides less traction and/or the corner is more flat, we might need to develop more rear traction on acceleration. Just giving the car more rear traction, period, does not help us if the car becomes too tight in the middle of the turns. We could end up with the reverse of what we need by going to a tight/loose condition.

We must develop more rear traction on acceleration only. There are ways to do that without changing the handling at other points around the racetrack. Rear steering the rearend is one way. This must be accomplished only while the car is accelerating and not in the middle portion of the track.

We could always use more bite off the corners on dirt. To give the car more rear traction, we need to understand a little about the dynamics at work on the car when we are accelerating. One way to reduce wheelspin is to reduce the "shock" of sudden application of throttle and torque to the rear wheels.

We can use lift arms and pull bars with various stiffness of shocks and springs to soften the application of power. More and slower movement is needed for slick conditions while less movement is correct for the tackier conditions. Another way to gain bite involves the use of a spring-loaded push-rod that allows a certain amount of forward right rear wheel movement to steer the rearend more to the left.

9 The Antis

Antidive and antisquat are mechanical influences that can help our transitional phases of entry and exit. Antidive helps prevent sudden nose dive on entry by mechanically resisting the downward motion of the suspension using the rotational forces created through braking.

Antidive is useful for both dirt and asphalt cars, but the trend for both types of racing involve promoting front end dive on entry to get the nose down for improved aero efficiency and downforce. So, we see teams actually using pro-dive on the left front of the cars to quicken the movement down.

Antisquat results from the third link trying to straighten out or become more horizontal as the car accelerates and as the rearend desires to rotate. The more third link angle you have, the more anti-squat there is. The lateral location of the third link will affect the distribution of load among the two rear tires that results from acceleration and antisquat.

Excess antisquat can be detrimental to corner entry. So, there is a limit to how much you can get away with and still have a decent corner entry. Roughly 8 to 10 degrees of third link angle is sufficient to promote antisquat and not hurt your corner entry.

10 Aero Package

The very last thing you need to worry about is your aero package. I'm not saying this is not important to some degree, but on many short tracks gains in turn performance outweigh gains in aero.

Still, the goals of a lower front end resulting in tighter spacing from the front valance to the track surface will enable a lower CG, resulting in less load transfer and a higher downforce loading. Both of these are positives and proper goals as long as the overall grip in the four tires is not compromised.

Try to understand how aero downforce is created and then configure your car so that you take advantage of every area where you could produce more downforce. Remember that drag is an important aspect of aero design. Do not seek aero downforce at the expense of aero drag increase.

Dirt car racers discovered the need for better aero designs some years ago. Just look at the Dirt Late Model cars and how they have evolved. The front ends are wedges that scoop the oncoming air up and over the car. The wheelwells are shaped to route air out and away from the front wheel wells creating a lower pressure under the hood and therefore added downforce.

The degree that you need to get involved with aero for your car depends a lot on what you run and where. Aero influence varies with the speed of the vehicle. There is an algebraic increase in both drag and downforce associated with increases in speed through air.