Sent: Monday, October 20, 2003 9:51
PM
Subject: [FlyRotary] temps behind
radiator?
Greetings,
In trying to make sense
of my latest cooling problems, I've thought of yet another variable (just what
I need <g>). When I initially installed the new Setrab oil cooler
(behind the radiator), the oil temps never got above 180F, even in a climb to
10000 ft. The water temps were being controlled by the thermostat, so
they were 180 as well. Since then, I've tried to even up the water and
oil temps, by blocking off part (half) of the radiator, and removing the
thermostat. The goal was to figure out how large the Rev 2 radiator
needs to be. The initial indication is that this may have caused my oil
temps to be high. Water is up to maybe 160F max, so there
still seems to be too much radiator, but oil will top 220F if
allowed.
What has just occurred to
me, is that by blocking off part of the radiator, and raising the water
temp, I'm probably increasing the air temp that the oil cooler sees
behind the radiator. Has anyone measured the air temp behind
the radiator when the water temp is around 160 or 180? I'm curious just
how hot this is.
Bottom line is that I'm
thinking I may have to put the oil cooler in front of the radiator,
and leave the radiator oversized enough to compensate for the hot air from the
oil cooler. FWIW- if you've got the space, I highly recommend
keeping the oil and water cooler separate, as most everyone (with sense)
knows already :-)
Cheers,
Rusty (need beer to cool
my brain)
Rusty, my cooling
capacity model indicates that the stock Mazda cooler does not adequately cool
at speeds below approx 120 MPH with high power setting (like 150-160HP or
above) . The model indicates that up to that point at least, the
radiators are carrying the extra load of the oil cooler or at least
trying. Since the oil specific heat is only about 1/2 that of water, it
requires approx twice the flow rate (based on that difference along) of
coolant to bring the same amount of heat to the cooler. Then if
the airflow through the oil cooler is impeded in any way (or you are pumping
hot air into it) the situation becomes worst.
I know its just a
simple model, but it seems to jive with my experience with coolant and
oil temps.
You may not get
this message for days as for some reason none of the 7 messages I posted
yesterday or today have gotten through to the list. I must have pissed
Marv off over something {:>) Or else been filling up too much of his
disk space.
Ed
Anderson