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Old 02-22-2015, 01:11 PM
78w72 78w72 is offline
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Join Date: Nov 2007
Location: iowa
Posts: 5,598
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coolant to heat the carb does work, rather well actually. 80-81 turbo 301 t/a's used the coolant to warm the carb plenum, heats up to an effective temp in about 3 minutes. the turbo 301's design has an aluminum carb plenumn that is raised & not actually connected to the intake or heads like a traditional pontiac v-8. pontiac used a dual action t-stat that would allow flow to the plenum untill a certain temp, then cut it off & allow flow to the rest of the cooling system as normal.

as a performance mod, i tried blocking off the coolant flow to the carb plenum & in the summer it ran ok but i never noticed any real performance gain, but once fall set in or early spring, anything below about 55* & the engine would stumble & run very rich from fuel collecting at the bottom of the plenum. it would take almost 20 minutes for the plenum to even get warm. i hooked the coolant lines back up & within a few minutes the plenum was nice & hot & the car ran so much better on cold days & basically the same at operating temp.

so GM knew coolant heating worked & as tom v said, the coolant does get hot enough to work & does it very fast.