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JFP in PA · 07-02-2011, 09:39 AM

An oil weight for track usage gets into some interesting trade offs; many use 15W-50 or 20W-50, others like 10W-40. Some even change weights for specific track layouts.

You are overlooking the impact of oil "displacement" under repeated high RPM's; just like the G force phenomenon, repeated high RPM usage floods the cam covers with oil faster than the oil can drain back, resulting in low oil levels in the sump. This is even a problem on drag cars, where with out specific modifications, more than 85% or the oil capacity can be up in the top of the engine by second gear, starving the pump. This is one of the reasons Porsche created the “X51” option with additional scavenging pumps in the heads and a “northwest passage” oil return that by-passes the engine and routes the oil directly back to the sump. There are also aftermarket kits that do much the same as the X51 package, but they are very expensive and require removal, drilling, and sometimes welding on the cam covers; so they are not for the “faint of heart” due to the fact that your cam covers a machine matched to your heads and cannot be replaced if screwed up.

Oil control is a lot more than just weight selection; it is knowing where the oil is, and where you want it to be........

07-02-2011, 09:39 AM	#4
JFP in PA Registered User Join Date: Feb 2005 Location: It's a kind of magic..... Posts: 6,458	An oil weight for track usage gets into some interesting trade offs; many use 15W-50 or 20W-50, others like 10W-40. Some even change weights for specific track layouts. You are overlooking the impact of oil "displacement" under repeated high RPM's; just like the G force phenomenon, repeated high RPM usage floods the cam covers with oil faster than the oil can drain back, resulting in low oil levels in the sump. This is even a problem on drag cars, where with out specific modifications, more than 85% or the oil capacity can be up in the top of the engine by second gear, starving the pump. This is one of the reasons Porsche created the “X51” option with additional scavenging pumps in the heads and a “northwest passage” oil return that by-passes the engine and routes the oil directly back to the sump. There are also aftermarket kits that do much the same as the X51 package, but they are very expensive and require removal, drilling, and sometimes welding on the cam covers; so they are not for the “faint of heart” due to the fact that your cam covers a machine matched to your heads and cannot be replaced if screwed up. Oil control is a lot more than just weight selection; it is knowing where the oil is, and where you want it to be........ __________________ “Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein Last edited by JFP in PA; 07-02-2011 at 10:09 AM.