I think I've an idea why the difference between the floor and our carpet is so great. At a lot of tracks when the carpet is laid, it takes a while to clean the dust off the racing line and bring the grip up. However as we have to keep all our kit outside in a shipping container (during winter remember) , the carpet is inherently ever so slightly damp. I think this keeps the dust down and has the carpet grip levels close to optimum right from the off.
I do have the solution though, burn the carpet and just run on all slippy stuff
