All,
Been following the EWP thread with
interest....
Sooooo...., actually knowing little, but suspecting
much:
I'd suspect that Mazda designed the water pump and
flow characteristics to provide adequate cooling for an idling engine in
Phoenix in the summertime. I'd also bet that the majority of time, a
car is sitting at idle, as opposed to cruising down the freeway at 70
mph.
My suspicion is that the water pump is designed for
some arbitrary flow rate that will be adequate at idle - and at normal
cruise (with it's attendant increased airflow). I'd guess
that the pump is flowing a much greater volume of water at high RPM's than
is really necessary, because the pump impeller is not variable. The
engine temperature does not remain cold, because the thermostat closes,
either completely or partially to keep the block temperature at
180-deg.
Have ya-all ever driven a car with a stuck-open
thermostat...? The engine never warms up. Runs OK, but builds-up
sludge and carbon inside.
Therefore (if all that's correct) an EWP
will not have to pump a correspondingly greater volume of water as engine
speed increases. I agree that it will take more flow for a higher
horsepower, the question remains: "What MASS of water per unit measure of
time will cool 180 HP...?"
Here's a suggested test for someone with an engine:
Run a rotary with an EWP and radiator combination (no temp
regulator) (may need a fan).
Run the engine at idle, until the temperature stabilizes at
(say) 180-deg.
Measure the flow rate required.
Increase the RPM's to 2000, and increase the flow rate (if nec) to
stabilize the temperature at 180-deg.
Measure the flow rate required.
Increase the RPM's to 3000, and increase the flow rate (if nec) to
stabilize the temperature at 180-deg.
Measure the flow rate required
Jack Beale
----- Original Message -----
Sent: Monday, November 08, 2004 3:31 PM
Subject: [FlyRotary] Re: EWP Info- Lynn?
As I’ve suggested
before, I don’t see saving power consumption as a reason for considering an
EWP, especially considering the losses in converting mech energy to
electrical and back again.
I think the
biggest chance to save power on cooling is if Mazda is providing
way more than is necessary at our cruise rpms. I have to suspect
that's the case, since Todd is running just fine with only 9.X
gpm.
Al (I swear I will not say
another word about EWPs; that beheading thing is just too scary)
Ha.
Don't worry, my wife would kill me if I stained the carpet
:-)
As for EWP's
saving power, you'd think that the first people to jump on that would be the
racers. I know that these pumps are sold to drag racers, but I can't
say that I've heard of other types of racers using these pumps.
Hey Lynn,
-Are EWP's
against the rules?
-Has someone
determined that they don't save any
HP?
-Has someone determined that they won't cool the engine in
racing conditions?
Cheers,
Rusty (just
can't have any fun on this
list)