What is the diff. between a/c and max a/c? And how do the effect the power of these trucks? Do I lose a lot of HP with the a/c on? How long after I turn it off do I get it back? Thanx in adv.

 

A/C opens the vent and brings in fresh outside air... MAX A/C closes the vent and recirculates the air, which allows faster cooling...

 

Max is suppose to help mpg!

 

The minute (second) you go WOT the AC shuts down ....

 

As mentioned, A/C takes outside air and cools it, and MAX A/C takes the already cool inside air and recools it.

When you go WOT, the PCM commands the WOT A/C cutout relay to shut the compressor off, so there is no hp loss.

 

All responses are correct so far.

Only thing I'll add is that if you leave it on MAX. The inside air humidity level drops and therefor the compressor is running less and the engine uses less power to keep it cool.

Another side benefiet is there will be less water in the system which is allways a good thing. Especially in the rain or fog.

If your getting to cold with it on max? leave it there and turn up the temp dial.

(just got done being an automotive HVAC engineer for a year)

WOT

BTW: "MAX" really is a misleading term coined many years ago in the US. It ought to be called recircut instead.

 

On my ole DSM car ('92 Eagle Talon Tsi AWD), it had a setting for that would maximum or normal. If you put it in the normal position (by the push of a button) it would actually engage/disengage the compressor while cruising. It was quite a trip going down the road and feeling the power kick in and then out. Such a dumb idea.

Anyhoo, it also had the option of inside or outside air, and this was an entirely different dial that did this. So you could have inside air w/ normal or max, or outside air w/ normal or max.

 

Originally posted by wydopnthrtl
BTW: "MAX" really is a misleading term coined many years ago in the US. It ought to be called recircut instead.

"Recirc" is seen very often in imports.

Also, when I turn on the AC, the engine revs up like crazy. When I slow down to a stop, the truck sounds like an aircraft about to take off..

 

I understand that the compressor is shut off the minute you go WOT, but i'm not sure that you arn't losing any horsepower. For instance, I ran WOT in my former 99 V8SHO and it shifted from 1st into 2nd at WOT at 6900rpms, but when I tested it again with the A/C on, the WOT shift was only at 6500rpms. This was replicated again. My Lightning seems to do a similar thing.......

When I go WOT normally, it shifts at a hair below 5200rpms, but if I do the same thing with the A/C on, it shifts into 2nd at about 5100rpms which is a hair lower.

 

So there is some loss when it is on? Does anyone know how much? I heard about 10hp.

 

my engine revs up like crazy too, when the a/c is on, is this normal??

 

i had that MAX a/c on today, and I did not notice that it was any colder. But now I will always use the Max A/C

 

maybe its because I dont own a lightning - or a supercharged vehicle of any sort......but what does WOT mean? (im guessing its related to your boost......?)

 

Wide Open Throttle, even a weed eater will go WOT.

 

Originally posted by jefflaws
Wide Open Throttle, even a weed eater will go WOT.

LMAO!! I guess that means 0-60 in 5.2 grass clippings.

CrazyFoo, I thought your truck was silver. New paint?