oldred95

Up until my stock alternators death at 193,000 miles it never had a drop issue at WOT. I switched from the small case CS130 to the big case CS140 and noticed the WOT voltage drop right off. Its like the alternator was disconnected past 4500 rpms. It was very noticable with the head lights on. Honestly I haven't paid attnention to it lately but I haven't noticed it doing it. Then again I haven't driven at night much either to see it in the lights as they dim. I'm clueless as to what it is. The alternator works great otherwise.

marlboroman71818

Not saying that it is belt slip or or is, but he could still be experiencing full boost and the belt slipping on the alternator also. Can you manually select a gear and use part throttle thru the rpm range and see if it is slipping. If it does not stop charging then I would say it is belt slip, If it does stop charging then I would say you have a different problem.

thunder550

iTrader: (70)

Swapped alternators, still does it. I have a tighter belt coming on Friday, so we'll see if that solves it.

thunder550

iTrader: (70)

Tighter belt didn't help. Seems to be RPM related....WOT at lower RPM doesn't do it but once it gets up higher it does. Any other ideas?

dhpro

iTrader: (3)

E-fans? Maybe try underdriving ur alternator...cud be it just doesnt like the torque/rpm at that range...hook up tuning software and get some feedback. Ask an elec engineer like DrX (Grant), he might have an idea...I've had voltage bounce ever since I put e-fans on. I put a 145amp in and did the Big 3 wire upgrade and it helped, but no cure ($250 later). R/

oldred95

I used the stock length belt when I put my CS144 on which actually made it a little tighter. The tension has to travel back a little further then original and the spring has got some serious tension on it at that point. I'm like you, I don't think its belt slip. The belt isn't glazed or burnt looking at all. I think it may be something with the regulator. Maybe it can't keep the voltage under control and it shuts off until the rpms come back down. I know mine happened right around 4500 rpms. It was like a switch was flipped and it stopped charging. I haven't noticed it so much lately but with my new cam I will be shifting at 6000-6200 so if its still doing it I bet I notice it a lot more.

2005 Silverado

iTrader: (19)

Try a little looser belt, see if the belt tension is to tight and causing a bind when spinning it up high.

Dustin

BlackGMC

iTrader: (31)

Mine was doing something similar, when I had the battery checked and it was bad. Not bad enough to cuase the truck not to start but bad enough when it was a large load the volts would drop. Just stop by autozone and have them check it real quick.

LaSinister

Just an Idea, but maybe its the wire that goes from the alternator to the junction block that is somehow corroted?? Maybe it can't handle peak current at those high RPMs.

skeet

iTrader: (18)

chris check your spark plug wires, make sure all 8 of them are seated, ( snapped all the way on) i just went through this.