The first thing that we will deal with in our Chassis Set Up 101 is air pressure. Simple everyone does it but most people only do it cause that’s what you are supposed to do and don’t know what it does in relation to your starting set up and the rest of the car.
I will go to an extreme so you can see exactly what an air pressure change does, I am going to put a basic set up on the car with the air pressure set at 9 lbs. in front, 5lbs in left rear and 10lbs in right rear and we put on scales and the car has even weight across the rear.
We start the night out and the car is fast and all is good, so like most tracks the track starts getting drier and slicker so the first thing you do is let the right rear air down. In this case we are going to 4lbs (I never go this low) and we go out in the feature and the car is way to lose. Why did going down on air pressure make the car looser?
First off, on the scales you had even weight across the back when you had 10 lbs. of air in the right rear but when you go down to 4lbs of air in the right rear it brought your cross weight or left rear weight up to say 40 to 50lbs left rear heavy. So you lost your balance in the car.
Not only did you lose the balance in the car, the air pressure change reduced your stagger and the tilt in the car. And the car is now loose because it stays on the right rear to long. Normally this is when the car feels skatey and you can’t kick the throttle up quick enough. I would say 75% of the racers make this mistake.
The fix – first you have to know what a change does when you make it. This is just a simple air pressure change no big deal right – wrong, you have to know when you make a change how to get the balance back in the car.
Set up is very simple, I have just have 2 things that all changes are based on 1) I want to pick the throttle up sooner and 2) I want to be able give it more throttle. If you ask yourself these 2 questions after every time you race and make changes the answers will fix you set up issues.
Getting back to the air pressure issue, what changes do you do when you change air pressure?