When one has their your motor enhanced for power, the tuner will typically provide two tunes; one for 93 octane and the other for an alternative fuel (i.e. E85, Sunoco or VP race fuel). One of the issues faced by folks racing their TH is getting the 93 octane fuel out of the tank in preparation for the filling of the race fuel. There are several recommended methods but one I found interesting, based on a video, appears to be the. Hopefully this information is useful. Happy hunting!