I did not know this! So everytime im about to get in a race from a light i really dont need to turn off my a/c and sweat my a$$ off for the next 30 seconds?!?!

 

The heat exchanger for most heater systems in autos is fairly small, like less than one square foot of frontal area. They are also not as thick from from to back. In comparison to the size of the radiator, it's probably about 1/10th the size, so the amount of heat removed from the coolant must be similarly smaller. I have no data on BTUs for heat exchangers, but with radiators size matters. So my guess would be turning on the heater might help to reduce temperatures in the engine, but probably not significantly. Once the car is up to speed the radiator is very efficient at removing heat from the coolant (unless it is clogged, or the water pump is failing).

 

I have a vacuum switch that cuts off the compressor when
manifold vacuums get low enough like when nailing it.
The compressor comes back on when I get out of it and
I never notice the difference of the air temp coming out
of my vents. There is enough compressed gas reaching
the orifice to carry thru the occasional nailing sessions.
The compressor comes back on once vacuum gets
high enough, it starts compressing again and catches
up real quick. The switches were advertised on TV in
the 70-80s as the PassMaster. Anyone remember this
product? Works great and I have an indicator light to
tell me that it is actually working when it should be.

 

Just turn off the AC when you want full power and NEVER use it at the track due to condenstaion dripping from the car on to the track surface. I built an electronic circuit that uses the signal from the throttle position sensor to cut power to the AC at WOT in case I forget to shut it off when I hit the throttle on the street. Since you might only use WOT on the street for a few seconds at a time it doesn even effect the AC's ability to cool the car.