MichelJ,
Yes you can, I don't know if this is the best place to do this or not but I have intentionally made a couple of tracks more slick and the grove a lot smaller by going to C:\Games\Infogrames\Dirt Track Racing 2\data\Tracks\"whatever the track name is" then open the track notepad file and it will say.[GRIP] below that it says "inner grip" and "outer grip" raising the numbers after those gives you more traction. Also changing the numbers on inner and outer radius moves the groove.On the one that I did the numbers seem to start between turn 3 and turn 4. I hope this helps.