I'm currently using Mobil1 5W-30 and a Mobil1 filter. My pressure stays between 50 and 60 PSI all the time.
I use the lighter weight
synthetic for the following reasons. The
oil in my SPF never really gets that hot due to the
oil cooler. Since it is typically at around 180 degrees F the viscosity of the 5W-30 is adequate. The lower viscosity
oil is better able to move through the plumbing, filter and cooler thus producing less line pressure loss. I live in Connecticut and like to run the car every 2 or 3 weeks during the winter. The thinner oil flows well even on cold days (during winter drives I cover the oil cooler). Since most engine wear occurs during start-up, I feel the thinner/
synthetic combo offers the best protection against start-up damage. If you're intent on using a thicker oil at least use a
synthetic.
I have done a fair amount of research on oil filters. Much of it says Fram filters are low quality. Their advertising is light years ahead of their filter technology. The Mobil1 filter has 350 square inches of filter paper which is about twice that of the Fram. Just go to Yahoo and type in "oil filter comparison" or go to
www.frankhunt.com.
I would be very afraid of oil additives. I'm always amazed at how many owners use conventional 20W-50 and then add the additive. Why so thick? Do all those owners really think that Castrol, Pennzoil and Quaker State don't know how to produce an adequate product? Most additives are snake oil. I had an uncle who used to add kerosene to his motor oil, he would swear on a stack of bibles that his cars ran better. Remember when STP was the rage?
In summary - consider the synthetics, use a high quality filter, use a viscosity that is appropriate for the kind of driving you do. Remember, very high oil pressure can be a sign of lack of oil flow. If your driving is to and from shows the thinner oil is a must. If you live above 3,500 rpm then the thicker oil may be a better choice. Change the oil a lot. I change mine every 2,500 miles. Considering what I have invested the $40.00 seems cheap.
Bob