Hopefully as a start you just ended the argument about how much power it
takes to run an alternator. I would have to guess a max of 2hp with a pretty
good load on it.
I do not agree that the same flow at a lower head pressure is equivalent
cooling though. I think and actually quite certain the head pressure is very
important. We have monitored it on the dyno and seen numbers over 40 psi on
very well designed endurance engines. Something that has to make 850 hp out
of 3 to 3.5 liters for 24 hrs. Did a 3.5 Nissan a little while ago 830 hp at
7200 30 psi in the block for coolant pressure. Ran great..
As far as cavitating the pump you generally just change the drive ratio to
suit the rpm of the engine. 3000 to 3500 at max rpm is about right for a SBC
and most others. cutting down the impeller might be another way but it is
hard to uncut them if you go too far.
Dave
> -----Original Message-----
> From: DrMayf [mailto:drmayf@teknett.com]
> Sent: Monday, March 14, 2005 7:24 PM
> To: Jon Wennerberg; Dave Dahlgren
> Cc: land-speed@autox.team.net
> Subject: Re: FW: electric water pump and thermostat
>
>
> Oops... Jon...
>
> Watts = E x I 1 Hp equals 746 watts 3 hp = 2238 watts 2238 =
> 13.7 volts x I amps I = 163.35, oh hell 164 amps.
>
> conclusion right , you forgot to multiply the 54.5 by 3 = 163.5 amps. A-
>
>
> Heres is where I see thing in a diferent perspective. Both pumps have to
> pump against the orifice of the thermostat. The mechanical pump is driven
> by the crank or cam and as rpm goes up, the head pressure goes up
> accordingly. As the head pressure goes up pumping against the orifice the
> mechanical pump take significantly more that 2 or 3 hp to
> operate. The elec
> pump is a consyant pumpinmg speed and can pump the same amount of water at
> lower head pressure so those motors are reasonably small. If the
> flow rate
> is correct then there should be no hot spots unless you have a chevy. :^}
> because the water is moving past sufficiently to moving cooler water into
> that location.
>
> mayf, off planet in Pahrump
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