Someone posted a thread a long time ago about doing a dyno with and without the a/c on. With the a/c on... the truck was retarting the timing. Ill do a search to find the link.

Here it is... https://www.performancetrucks.net/fo...t=Timing+A%2FC


here is a little more info... https://www.performancetrucks.net/fo...t=Timing+A%2FC

Hope this helps

 

mine feels slower w/it on

 

Ok, I was driving around last night in the rain without the defroster on and slamming on the gas in 2nd gear I could barely get the tires to spin. Most of the time I couldn't. I then turned the defroster on after about 10 min since my windsheild was fogging up and just a blip of the gas to 50% throttle it would just spin and spin. There's something def happening for the better with the AC compressor running. I'll have to ask Jesse next time I talk to him what exactly is going on.

Joe

 

I thought the NBS trucks had a switch that cuts the compressor off @ WOT???

 

Was your truck cold? Timing is pulled until you are up to temp.

 

Nope, this observation was noted after about 15 minutes of driving at full operating temperature.

 

AC on runs your fan to keep your motor cool. Cooler motors run faster.
BUT! I can tell you that I (stupidly) left my AC on while running down the 1/4 mile and ran .8 seconds slower than avg...
Running the compressor is a load . Yes, it pulls timing. And slows you down. That's why electric fans are great to run in the staging lanes. Electric water pumps are great for the drags too, but suck for the street.