hehehe...wonder what it would do with gear
oil in it? hehehe
Actually I think the second number is just a relation. If you start out with 10 weight
oil (low viscosity), then it doesn't make sense that it would thicken to 50 weight when hot.
So to answer your question, a 20W50 would be thicker at temp than a 5W50.
So it never gets over 45 psi even at wide open throttle? I really don't think the higher weight oils will help you. You may just wanna swap pumps....they're only $40....wouldn't take very long.