>> Keith,
     >> What's the difference between a radiator core and an
     >> air-conditioning core.
     >> George (down under)
     >>
     >> George,
     >>
     >> The major difference is around 300 - 400 psi in the a/c core v.s.
     >> around 20 psi for a radiator. A/C cores are thicker walled round
     >> tubes to prevent them from distorting when subjected to the hgh
     >> pressures in the system. Radiator cores can use a rectangular tubes
     >> with thinner walls and will have more surface area per square inch
     >> of radiator surface, hence better heat transfer.
     >>
     >> Joel
     >
     > Aircon cores are also generally a thinner package, while heater cores
     > are significantly thicker.
     >
     > Keith Wood

    Thanks Keith and Joel,
    The reason I ask is that there are many GM aircon cores out there
    being used
    as radiators. Generally they appear thicker (not thinner), than the rad
    cores, perhaps 3 to 4" for the GM aircon cores and about up to 2"
    for the
    Rad cores.
    I believe the suggestion to increase the pressure in the Radiator to
    about
    24psi to protect against boil-over at altitude might put the radiator at
    risk, if it's rated at only 20 psi - would there be a safety factor
    built
    in or would it be running dangerously close to pressure limits.
    George (down under)


    ---------------------------------------------------------------

    It depends on which one you are talking about George.
    There are two heat exchangers in AC systems. One inside the
    vehicle and one up front next to the rad. The one up front has
    large frontal area and is thin similar to a rad.

    The one inside the vehicle has frontal area constraints and aerodynamic
    drag or pressure loss is not a consideration. It is dumb to use it
    in a way
    it was not designed for. The typical car rad is a better match for
    aircraft engine cooling use.

    Any air/fluid heat exchanger works better if thin. The ultimate heat
    exchanger has infinite frontal area with infinitesimal thickness :)
    The first half does three quarter of the work.

    So far nobody has blown a rad with up to 30 psi.
    --
    Paul Lamar ...No rotor no motor.


    Most current radiators are for low pressures, ie approximately  psi
    20 or less.  Most are now using plastic tanks and connectors to the
    cores instead of solder.  As suggested elsewhere, a good radiator
    repairman  can fabricate a soldered radiator and tanks which can be
    tested to much higher pressures which will give a good safety margin
    and reliable service.

    A/C condensers may not have as good of a heat transfer due to their
    high pressure design using thicker walls.  I'm sure they would be an
    excellent choice for oil coolers.

     Joel

Joel,
Th local aluminum radiator supplier recommends the plastic tanks ( on his
website) before I contact him, what is the recommendation on the plastic
tanks - I heard they were prone to failure much more quickly than the full
aluminum ones. I'm sure the racing people use full aluminum, perhaps for
that reason.
George (down under)


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