Originally Posted by Maximo

HPI Purple 30%..i think they only have 1 fuel.....We found it gave us the best lapping between the sleeve and piston...We found many of the race fuels were just too greasy and the pistons would never size to the sleeve in any reasonable amount of time...The older Picco's we ran were extremely tight and breaking in with something like OD 30% would result in a beat up rod and a engine that still jammed the starter box at 3 gallons...But with the HPI we could get a great fit much earlier, in less then half the time..then once we knocked the pinch down we switch to the race fuels......Thie method seemed to give us the best breakin with the least amount of stress on the internals...... However it sure grinds my gears having to go pay more for my breakin fuel then the high grade fuel we race with tho LOL