I suggest putting together a resume type paper about your car and writing a formal written proposal to companies you are wanting to solicit sponsors for. I am not trying to be mean but just asking for sponsors on a board is not going to win you favor with companies cause it is unprofessional and they won't likely take you seriously.
But like I said treat it like a job and make out a resume detailing out your car. Then write a formal written letter to the company or companies you are wanting to get sponsorship from and write things in the letter explaining what you are asking for, what you can do for their company (this is the most important piece cause they want something out of you as well if not anything else exposure of their stuff on your car at major events), what shows/races you have done, and what major races/shows you are planning to do within a 12month perios of time. You want to be as professional as you can while making it look like they would be losing something valuble if they did not back you in some form or another whether it be free parts or a discount on their parts.
I hope it goes well for you. Good luck
