ok so i was over at me buddy's house and we decide to change his oil, takes off his filter, and then starts the car up. he holds the rpm's fairly high for about 10 seconds, and shuts it back off. i asked him what the hell that was about and he said it helps to get the old oil out of the engine. to this i laughed alot. i tried to explain to him that it probably wasnt a good idea to do that. he said it doesnt matter and does that on all his engines from cars to lawnmowers. btw, from filter and generic oil were used.