Thanks for the advice. Yeah I guess turbo indoors = crash at the end of the straight!! Have turned it off.
Found this on the subject:
http://fiveeight0sixsix.wordpress.co...-esc-settings/
It seems that boost start rpm and boost timing acc fine tune the motor power band. So you can tune it for any particular track infield. It certainly took a few reads to get it sorted in my head!