we run rc car engines on higher nitro. I use 20% nitro for bashing and racers use 30 or 35% nitro. also the oil content ranges from 10-12% for racers (those engines dont last too long with such low oil) to about 14 - 16% oil for general bashing. I still sometimes add some Klotz castor to my car fuel, but not always. I run 14 or 16 % lube in .15 and .21 car engines...you notice performance and tuning decrease with oils above about 16 percent

I like HPI Power fuel and Traxxas Top Fuel

most rc car people dont have any idea what castor or synthetic oil is and if it is in their fuels

other than that it is pretty much the same.