[quote=RapidusMaximus]Not to start a keyboard war but I’m curious as to what viscosity everyone runs in their race car and why. I’ve been involved in some discussions related to rpm, engine water temp, fuel preferences, 1/8 mile vs 1/4 mile, cold starts, outside air temp and so on. The discussion started relating to cold starts and how hard it may be on the engine with a 20/50 oil and oil system components, also gas vs alcohol related to water temp, and of course the hp differences related to viscosity…what say the masses… [/quot

About the only thing that matters in terms of viscosity for race engines is bearing clearance. Typically race engines only operate in warmer temps and the engines are usually up to temp before max power is applied so that leaves bearing clearances as the primary issue. Modern engine design has trended towards tighter clearances and lighter oil for awhile now. Lots of "high tech" motors are using 0 weight oils. Old school guys still go with wider clearances and heavy oils.