Auto Racing: A bumpy dirt track, spring stiffness, street tires

Question
I raced my new 4 cylinder endero last week and it was a mess. During the hot laps it handled good, but when I raced the feature I couldn't keep it strait.The track got really bumpy. I changed the struts and hope that helps this tonight but i don't know if thats the only problem. I think I might be running to much air pressure too. I have to run street tires. I am running 13 inch tires; I may go too 14 inch. So back to what is happening, When I go into the turns and hit the bumps my car will jump really side ways.It slows me way down. When I had a smooth track I could keep up with the leaders. Now the problem got worst as the race went on thats why I am thinking tire pressure. Can you help me out on where to start.Thanks.

Answer
Hey James:  

I don't know a lot about dirt, but I think you have too much spring stiffness in the car.  Try reducing all four by about 25 pounds each and see if there's an improvement .  It sounds like the car is simply bouncing off the track and losing its traction entirely.

If that doesn' thelp , try increasing the spring rate (stiffness)  Keep LOTs of notes, and only change one thing at a time.  Lap times are the answer to whether something is working , helping or not .

I would say that with street tires, something in the area of 23 to 25 pounds might be about right, Much more and the car will be slippery. You can usually tell if your pressure is too high if the car feels "light on its feet" .  It should be easy to steer, but not skittery.

Please let me know what happens, I may then be able to help someone else.

Good luck

Dan Liddy
Sarasota, Florida