For maximum performance and protection with a minimum of parasitic drag Royal Purple XPR 5W-20 (part #01011, quart bottle)(formerly Racing 11).
If you are racing in a class and want a light viscosity racing oil that will give you a competitive advantage even if your competition is also running a racing 20 weight oil. This is what you get that will still give you unparalleled protection and film strength with that ultra low parasitic drag.
A still viable 5W-20 with excellent but less than XPR protection and performance is our new HPS 5W-20 (part #31520, quart bottle).
If you want to use a 20 weight oil because that is what Ford recommended for our cars due to CAFE, then at least upgrade your protection to a more appropriate level for these rather powerful supercharged engines and use one of the above choices.
The infamous Terminator tick is a result of guide wear, over heated guide wear, but none the less GUIDE WEAR.
Is more wear protection a good investment for a Terminator engine? Duh?
What about switching to a 5W-30 weight oil?(the second number is what counts most here since that is what the oil will behave like at operating temperatures, as opposed to the 5W- which is the cold flow rating) That's actually what was used in less powerful earlier versions of basically the same 4.6 DOHC 32V engines that also have the same internal bearing clearances, so why not? After all Ford is currently resorting to a 5W-50 to get two of it's high performance models through the incredibly rigorous near legendary Ford Durability Testing. The "grocery getter" 2011 5.0 Mustang GT takes a 5W-20 oil but Ford bumped the oil for basically a very similar 2012 Boss Mustang 5.0 engine to 5W-50 oil, that is 3 viscosity grades thicker!
For endurance racing with elevated oil temps, or longer service life in the presence of higher than normal racing levels of fuel dilution or extended drain interval street usage use Royal Purple XPR 5W-30 (part #01021, quart bottle)(formerly Racing 21). This is what I am using.
A still viable 5W-30 with excellent but less than XPR protection and performance is our new HPS 5W-30 (part #31530, quart bottle).
Royal Purple SAE 5W-20 (part #01520, quart bottle) and Royal Purple SAE 5W-30 (part #01530, quart bottle) in the older API-SL formulation were both a very robust oils and could be used with fragile Terminator exhaust guides with a high probability of little to no guide damage even in fairly highly modified, highly heated engines.
HOWEVER: The API oils of today are now an API-SN and are limited in the amount of Phosphorous that can be used which also reduces the Zinc because they are used together in the ZDDP -> Zinc dialkyldithiophosphate COMPOUND, which is the primary anti wear additive. It has not been removed but it has been capped.
Conclusion? Today's current API-SN oils from any oil company are less protective against wear than the previous oils were. This is why I recommend Royal Purple HPS 5W-30 for even bone stock Terminators that might never see any track time at all.
