"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
Ken Powell wrote:
Paul,
You are always after us for numbers so Ray has done his part. Note that this is the 2nd time you have posted Ray's research - thanks to Ray for sharing this with us and to Paul for posting it. I am giving serious consideration to a single pass radiator instead of a dual pass.
Ken Powell
kenpowell@aristotle.net
I was hoping for a lot more data from Ray :-)
I think the new rad is much larger than the old. It looks huge.
I would say the core is at least 19 by 22 by 2.5.
Ray measured it for me but I forgot to write down the numbers.
They are now using the water to oil heat exchanger.
The key info he is not telling me or did not measure was
the ambient temperature when they ran the cooling test.
Paul Lamar
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