From:
twelve_second_vega_REMOVE_547771_THIS_@yahoo.com
Cubic inches & horsepower production place the
greatest demand on a cooling system. Engines that are
required to operate under heavy loads & high rpm,like the
truck you mentioned, place additional demand on the
cooling system even though they produce little HP & TQ in
comparison.
A/C produces additional load and heats the air used
for cooling the radiator.
You observation is
correct, but high HP and TQ production requires additional
fluid capacity and surface area to a greater extent
than smaller engines producing less HP and TQ.
Again, in reference to the truck you mentioned, low
compression engines and the retarded spark timing common to
cars/trucks of the mid 70's and 80's produce incredible
amounts of heat.
195 thermostats (a type of smog
device) also raised engine operating temperatures to
incredible levels.
I like to use maximum surface
area in Vega's, but this isn't always easy to do. The
next best route is to increase fluid capacity and fin
count.
My 302 ran in the 220 degree range @ idle with a
16" X 21" X 2" 3 row having 12 fins per inch and 72
3/8" tubes running a 3/4" restrictor.
With my
13"X 21" X 2.5" 4 row having 16 fins per inch and 120
tubes total, the temperature will not go over 180 at
idle on a 100 degree day.
On the other hand,
most stock V8 Monzas I have seen without A/C have a
16" X 21" X 1.250" 2 row with 12 fins per inch and 40
5/8" tubes.
I have replaced one of these
radiators with a 4 row, at the customer's request, and the
engine ran not a single degree cooler. HP & TQ
production were low enough that the 2 row was all the engine
needed.
I always evaluate an engine's ability to cool (or
not) on a case by case basis. However, the phrase
'Bigger is Better' quite often applies here.
The
Vega is quite a challenge to cool...Robert
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