Who found out that the A/C pulls timing when on?
09-26-2003, 12:32 AM
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Re: Who found out that the A/C pulls timing when on?
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.
09-26-2003, 01:29 PM
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Re: Who found out that the A/C pulls timing when on?
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.
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?
09-26-2003, 02:44 PM
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Re: Who found out that the A/C pulls timing when 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.
09-26-2003, 03:07 PM
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Re: Who found out that the A/C pulls timing when 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.
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
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09-28-2003, 12:13 AM
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Re: Who found out that the A/C pulls timing when on?
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.
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.