has anyone else noticed that when you turn off the A/C the the EGT's go down 40 degrees in about 2 seconds and vice versa turning it on?? is that normal?

Does the compressor put that much strain on the motor that it increases EGT's 50+ degrees??? At idle there is no boost and turbo isn't even spinning basically..

thought it was odd... any comments on it/opinions?

Forgot to take your meds this morning Briano? ):h :joke:

I've never noticed it, but I'll check it and advise. JJ :)

has anyone else noticed that when you turn off the A/C the the EGT's go down 40 degrees in about 2 seconds and vice versa turning it on?? is that normal?

Does the compressor put that much strain on the motor that it increases EGT's 50+ degrees??? At idle there is no boost and turbo isn't even spinning basically..

thought it was odd... any comments on it/opinions?

Quite normal. The A/C Compressor will consume 15 HP all by itself. If you take into account the temps that arise from using it and the cooling fan kicking in, the HP useage can spike to 35 HP.

Of course these are numbers from Dynoing a truck with the AC on.

So yes EGT's will increase as you are loading the motor more. Interesting thing though, at WOT the AC compressor will disengage.... perhaps to increase available HP.

Interesting thing though, at WOT the AC compressor will disengage.... perhaps to increase available HP.

Yes that is what it says in the service manual. Not a very good idea in my opinion. Some guys with some sort of Ford truck/emergency vehicle were having a problem with this, when responding their AC wouldn't work. Places like here with the hills and a heavily loaded truck it may stay at WOT for 10 minutes or longer and if the AC is going to cut off at WOT you might as well not even have it. In my estimation this "feature" better suits a small rice car that goes around town than a big truck that is probably not going to miss that 10-15 hp all that much anyway.

Birken

Briano,

30*-40* increase in EGT's is what I saw on the attitude. JJ :)

I take my meds at night.. LOL

cool, thanks ya'll

My truck won't cool past 400 idling with A/C on.

My truck won't cool past 400 idling with A/C on.

yep, thats what I was seeing.. hit the off button on the A/C and it dropped 40 degrees instantly.

I got home tonight and the EGT's were sticking around 360° even after idling a bit. It's pretty hot out and I remembered reading this post this morning so I shut off the A/C to experiment. The EGT's (per Attitude) dropped a good 40° in less than 30 seconds, and continued to drop until finally going under 300°. Although I expected some load due to the A/C, I was a bit surprised that it fell that much that fast.

Although I expected some load due to the A/C, I was a bit surprised that it fell that much that fast.

exactly what I was thinking as well... thats why I thought it was odd..glad I'm not the only one.