"Speedy Goomba wrote:
Darin,
We've had the same results as you with mine and my fellow racer's testing. Our engines are quicker and faster the colder that are ran out. My ET's will fall off if i'm hotlapping.
We tune for 140 degrees as thats typically where we run them at (bracket racing).
My friends in stock eliminator run their cars ice cold to make a fast pass, but this is accompanied with double zero weight oil.
my question, what are you guys using for gear oil in the rear?
i'm currently using 75w-90 synthetic gear oil (mines street driven as well as raced)
We have tried some of the 40w Synthetics in the rear end and burned them up. We are back to the 75W. Our engine oil that we use in the Pro Stock engines is 005W. It like pouring alcohol in the engine. Its so thin it still shocks me that it can set up a proper hydrodynamic wedge in the bearing and carry the loads we put on them but it does. The additive packages in these oils are so complex its amazing. They have just the right balance of phosphorus and molybdenum and other assorted chemicals I am not aware of. One little tiny mistake in the formulation and they wont make power. These new Synthetics are a Mad scientist paradise. When they work they really work! Did you know that we can run our main bearings ALL YEAR! We never replace them unless there damaged and that almost never happens. We run .004 on the mains and .00375 on the rods and .002 on the wrist pins. If you tighten anything up more than that at the temps we run these things, you will fry the bearings. Someone here asked what piston to wall clearance we run. That depends on the piston design and manufacture. We use or should I say, test every manufactures piston. They all take different piston to wall clearances due to there design and metallurgy. We run CP pistons the tightest at about .007 and they seem to run the best so far. " - Darin Morgan R&D cylinder head department, Reher Morrison
