Your car insurance will not cover damage to your car when on a racetrack. It is not advised to even pursue this. Your insurance company will not like the fact that you have taken your car on a track. You the participant will have to pay for the repairs and damage yourself. You assume the risk.
There is insurance is for Third Party Liability. Covers other people and property, participants may injure or damage. Does not cover drivers personal injuries or their personal property damage.