What tires are you using btw? I went to a track for the first time ever the other day and it appears to be similar conditions. I took my Rustler, not my 8ight and I couldn't keep it on the track. I'm taking the 8ight next time though.
2wd on a dusty track takes a steady hand and very little throttle input. I tried running my jato at a MX track once... I gave up quickly.
That engine really wraps up fast. Almost seems like your idle is a bit low. It sure drops from high RPM's to low idle really quick too. I like engines like that. Would be dangerous if the track was a bit tacky!