At 06:22 AM 03/26/2005 -0800, Bill Babcock wrote:
I thought about that, it's why I think it will take some testing. I suspect
that at higher RPM the pump isn't increasing pressure linearly, there's such
a big range of RPM that it operates over. There's a good chance the block
pressure wouldn't change. The easy way to find out would be to put a gauge
on the block and try it.
I run one of Ken's super-duper water pumps, it's last years impeller
design, and I have done some mods to the water passages in the head. I run
a coolant pressure gauge, tapped off the back of the block where the stock
drain is. I find the increase of pressure is absolutely linear. With the
thermostat in place I have pinned a 35psi gauge. With a blanking plate in I
do not go over 30. These readings are at the end of straights, so figure
5500 to 6500RPM. I have not looked while winding out to 7000. Next time on
the dyno I will. I have replaced the 35psi gauge with one with a higher limit.
I have never filled my overflow tank, so my 16 lb cap is holding fine. I
was worried when I removed the thermostat, but no problems.
After looking at my pistons right out of the motor, there was no way to
tell which one was #4. They all looked the same. I never had that before
increasing the block pressure.
I am a strong proponent of raising the coolant pressure, I think it does
wonders to cool the engine more uniformly. Extracting heat is important...
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