This is the experience I've just had. take it for whatever its worth, I don't have much time to get on here anymore, but am killing a little time here at the airport, and would like to share.
I've researched "best oil for our cars" on this site and gnttype.org till my tiny little brain started to hurt. I just switched over to royal purple per recomendation of fellow member. I had been using mobil 1 for some time. There may very well be a better oil for my application and climate than royal purple, but my daily driver ttype seems to like royal purple a whole lot better. I had dropped the oil pan to change rear main, I also blew out oil in the radiator cooler with air hose through top port so it would drain out oil pump filter housing with oil filter off. I pulled valve covers and used a rag to soak up oil in rocker valleys. So with exception of little bit of oil here and there, I think I did pretty good job of getting old oil out of the engine. Probably overkill, but I'm weird that way.
Engine had been running pretty smooth with mobil 1, but I had a fairly light lifter tap at idle ever since bought the car. (115,000 miles)
I put in the royal purple and primed the engine, then started the car and could hear all my rockers/pushrods making a little bit of noise for about 20 seconds. Then engine went super quiet and super smooth, and has been that way ever since (put about 150 miles on it so far). No more lifter tap at idle. This is the first time I've been able to actually notice a quiter engine after changing oils, and I've spent a lot of time with this car lately learning how to tune and so forth. I don't know if this is normal or not, but with my ear closer to the turbo than the engine, I can clearly hear the turbo shaft spinning inside the turbo over the engine noise.
This is just my exp. Maybe I should add the additive thats mentioned earlier in this thread, but heck,.. I'm so impressed with results so far,... i'm scared to mess with it. :tongue:
