is it more effective to turn the a/c on during idle while cooling down before shutting off or is it better to keep the fan speed switched to the 3/4 position (with the a/c off) and let the fan turn on intermittently by itself. tia bill

 

If you get a turbo-timer you can put the AC on when the key is off (but the engine still running with the timer) which puts the fans on but the AC compressor clutch doesn't kick in because the key is off and the accessory power is not there (at least, that's the case with my Greddy turbo timer). Also I tend to shut the engine off, then turn the key on and off to get the timer counting down with the engine off but the AC turned on so the fans run on hi for a few minutes with the engine shut off.

Without a turbo timer I would think that having the ac on would cool better than not because the fans are constantly running, even though the AC compressor is running too. I don't have any data to back up that speculation though.

 

YES it can be very effective to run a/c while letting the car warm down.

 

A/C on or off, you shouldn't be letting the car sit for very long to "cool down" anyway. Once you get enough gauges and a PFC Commander, you'll discover that sitting there letting the car "cool off" only gets everything else hotter.

But yes, having the a/c on at idle should keep your temps lower, but if you have a PFC, you can lower the temps that your fans come on anyway.

 

Thanks for the response. Is it also better to remove the front air scoops to allow more air in or are those suppose to help direct air through the radiator and prevent escape through the sides of the underbelly.

 

I agree. Idling to cool the car down does heat up everything. I do run my AC after I've come in off the track though with the hood open.

 

That is a good question and I've been wondering myself.

Your talking about the little black half moon shaped things on either side of the rad opening? I don't like the unfinished look so I was thinking of putting some Touring parts in there. The Touring has cut outs for the fog lights.

 

I have removed those black half-moons and can say they make no difference at all. I have put them in and taken them out several times and no difference was noticed.
I also agree that idling definately does not cool things down. It is far better to just drive the last few blocks slowly because the airflow through the radiator is much better when cruising along at 30 than it is when sitting in your driveway.
I can also say that running A/C is not a good way to cool things down. When the pump comes on the condensor heats up feeding warm air to your radiator. In fact, in the summer time I am forced to turn off the A/C fairly regularly to keep water temps down. If your reasoning for running the A/C is to get the fans on then set the fans to run on a manual switch instead, it will be alot more effective.