What ever became of this? Was there some fix for this?

 

I think it was Fast4.8. Not sure what was the fix.

 

yea it was Fast4.8

 

You can't tell? My truck runs like a pig when the AC is on. You can tell a big difference in torque when going down the road at highway speeds up hills and stuff. The drag of the compressor also hurts torque.

 

No, it run terrible with it on. This is the only vehicle I have driven where it drives this slow with the A/C on.

The actual compressor doesn't seem to kill the power. Hell on my F-150 when the A/C is on you can't really tell...it does drain power but not nearly to the extent of the Z.

Any ideas why the hell GM programmed timing to be pulled when the A/C is on?

 

my guess would be towing performance. the cooling requirements are crazy from GM they rated for max gcwr, and 120 degrees up a 10% grade in death valley.

 

Hrm can this be removed via EDIT?

I don't tow a damn thing, Texas doesn't get quite to 120* (tho' it feels like it!). I best this is like the TqMgt thing GM includes isn't it

 

It was me, but I haven't really persued it much.

 

Thanks for the responses, now I love the power my truck makes. It used to be all about my comfort, f that

 

GM does it to resist knock. AC raises engine temp quite a bit at times, so to reduce the chances of knock it switches timing tables. Not everybody checks their coolling system to make sure its up to par. Not to mention clueless soccer moms.....in stop and go traffic.....while its over 100 outside....with 8 kids in the car.....A.C. on 110%....and they dont ckeck their gauges. things can get pretty hot. Most cars from the manufacturer are made to be idiot proof to some extent. In order to accomplish this, they take an awesome engine (LS1 etc.) and de-tune the **** out of it. So pulling timing to compensate for A.C. makes sense to me.