"Quirk, Kevin KA" wrote:

Paul,

I have read some cooling system info that says that there should be a restriction in the engine outlet passage.  The theory is that it helps build pressure in the coolant passages, minimising 'hot spots', air/steam pockets, etc.  One of the authors was Carroll Smith ("Engineer to Win").  The texts related to reciprocating engines, although the same principles should apply to us.

I believe that the Mazda factory race water pumps do not use a thermostat (standard system restriction) so they may use another method to build 'block' pressure.

Do you think this could be a problem when modifying the standard system?  Maybe the Racing Beat guys have experience in this area.

I am working on the cooling system of our 1st Formula SAE car so all of the newsletter info is of great help.  Unfortunately, they group leader is set on running an electric water pump.  The pump supplies maximum flow at just 10kPa so that should test the block pressure (or lack of) theory.

Regards,

Kevin.

The rad is a restriction and that is plumbed to the block outlet
directly. 

Ray Richardson of Power Sport just told me he increased the flow rate
of the cooling system from 31 GPM to 55 GPM by going to a single pass,
low restriction radiator from his original two pass radiator.
He says this was enough to make the cooling acceptable. 
This does not jibe with the need for a restriction on  the
output of the block. It would be interesting to put pressure
taps in several places in the cooling  system to see exactly what
the pressure drops are. I intend doing that with my system.

I would not run the electric pump. It won't work.  Hint.
Work out the HP. 746 watts equals one HP. P = E X I 
A mechanical water pump requires two to three HP. 

Paul Lamar
 
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