do I need a bigger alternator??
 

Hey guys I have an 02 silverado 5.3 and I recently did an efan swap, i put LS1 fans and a Nelson Harness, the install was fairly easy and I got a local tuner to turn the fans on, they cool great (was idling in 108° weather, and never went over 210°) but one concern is when I turn my compressor on (which engages both fans into High) while idling, my truck boggs down for a second or to and then slowly goes back to normal, I think this is due to my truck only having the stock 105 amp alternator, and also ironacally, instead of gaining mpg's I have lost in town mpgs since the swap..any ideas?

You and every truck around would benefit from the big 3 upgrade. In addition it wouldn't be a bad idea to have a bigger alternator especially if you have subs or other stereo stuff, but if it's performing at capacity it should be enough if all you added was Efans.

So do you think if I upgraded to a 145 amp, it would kick gas mileage up??

Depends on the tune. Mine idles high when the ac is switched on.
I'm still running the 105amp alt. with efans and have no issues what so ever.
Then again i don't have a stereo system.
Efans have nothing to do with gad mileage.

Well either way I guess more juice wouldn't hurt, I just thought maybe the extra load from the fan motors was causing more current draw from the 105 amp, and if I bought a bigger say 145 amp alternator it could do the job easier and maybe cause less drag on the engine?

yess a bigger alternator will help i did the swap and when i turn my ac on..my voltage drops for a second and the engine boggles a bit..it just takes alot of current to get the fans started..thats why it does that..a bigger alternator and better grounds will help

Thanks for the info! Much appreciated!