Well, based on my reading here I saw that several members have successfully used the stock 105a serpentine belt with the 145a alt (the pulley sits up higher). So I put the alt on and there was absolutely no way that belt was gonna go on. And it's a nearly 10 year old belt too, so nicely stretched out. Went to AutoZ and got me a 93" gatorback belt (designed for use with the 145a alt) and just got everything set up. The tensioner is tight. It's got a teeny bit of play in it if you push it in with a socket wrench. I'm assuming it's supposed to be this tight when new and then it stretches out a bit? Just had some concerns about breaking the tensioner as with the old setup the tensioner wasn't nearly as tight.

 

With the ideal belt length, the tensioner should be in the middle of its range of travel, centered between the 2 stops. You might need a slightly longer belt if the tensioner is wound up all the way to the stop.

 

Here's the GM part number for the belt that I used when I swapped in my 145 amp alternator, fits perfectly

12576451

 

Seems to be driving fine, so I guess the belt is fine.

Anways, the 145 amp alternator made NO DIFFERENCE seemingly in terms of the voltage drop.

Bud, when both of your efans kick onto high do you get a voltage dip down to like 13-13.5 volts?

I think I need the 2 pin harness and maybe the Blackbear overdrive pulley too.

 

Yea, my voltage dips a little when the fans come on high...I don't even notice them come on low though...

 

yeah, no notice with lows.

Do your headlights dim when the fans come on high? Mine do.