06GMC4X4

iTrader: (1)

After putting the MS3 cam in my car and having it tuned the voltage wasn't as high as before, was about 14.5v stock then dropped to about 13v. I then added the Powerbond 25% underdrive pulley and it stayed about the same. The alternator lasted about 3 years (20,000 miles) then went out (i figured it was time for it to go). I replaced it alittle over a year ago but have only put about 7000 miles on the car and my alternator will charge sometimes and then it will stop. My question is would putting an overdrive pulley on the alternator help save them or do you think I just got a crappy alternator? I'm going to replace the altornator this weekend but I just don't want this to be a yearly thing on a car that doesn't get driven much.

Thanks

Lopoetve

iTrader: (1)

what are you replacing them with? What brand?

greatskiiiier

iTrader: (10)

i had the same prob, exp the alternator went every 50 miles or so- it was re manufactured USA brand, eventually got a good one (after during 3 swaps) and its lasted about a yr now, stays between 13v and 14v, drops to 12/12.5 when under load (less when starting) but so far havent had any problems....

i think the location of the alt also makes it prone to get water in there and messing **** up- just get real good at swapping em and enjoy lol

Shea05

iTrader: (3)

what RPM are you reading the voltage at? 2000 RPM and no load is the way to read the charging voltage.

cdubbzz

iTrader: (11)

Damn I thought I was the only one with the voltage drop. My alternator is
<1yr old + brand new belt + Katech tensioner = tighter than a mouse's ***
but under load(3rd/4th gear) at high rpm's (5k+) my voltage drops the same (13.5 -> 12ish)

Back to orig question, overdrive pulley help save alt or get better alternator...?
And will this voltage drop be harmful (less spark etc)???
.

5301113

iTrader: (18)

x2 on overdrive pulley

06GMC4X4

iTrader: (1)

Sorry for the late response, I replaced it with the Delphi reman. I just put a new one on it yesterday (lifetime warrenties are nice) and it is keeping over 13v under a load again, so I'm not sure. I guess I'm going to go ahead and order a overdrive pulley for it and see what happens.

youguessit

I have experienced this too. Appearently alternators work extra well for the first year or so then their output goes down... If your underdriven on the crank you need an alternator overdrive pulley (automatics)... Btw feel free to call bs because this is just my conclusion based on my experiences. I really didnt mind the voltage going a lil low but when summer hits and you have the ac, headlights, radio, auto transmission, then it goes right above the red and the transmission has trouble shifting... The low voltage actually caused my car to throw shift solenoid b code...

jam01

during your cam swap did you tighten everything up. how is the battery, maybe a solenoid or fuse. if you still have problems check your wiring. maybe something came loose. good luck

jmilz28

iTrader: (13)

BUNCH of possibilities here.

Number one, factory voltage gauges are notoriously inaccurate. They are VERY relative.

Number two, amp output is more important that voltage. They are related, of course, but not the same.

Number three, OE alternators are pretty good. Delco re-mans are ok.

Just because it is a US brand, doesn't mean it's rebuilt in the US with US parts. A locally rebuilt unit would be good. A high output unit, like one from AlterStart, is your best bet. You need more output at idle.

Some other things you can/should do:
1. Get an Optima battery
2. Upgrade your big3 (alt to block and battery, battery to ground, engine to chassis ground)

This will optimze your alt's output.

An overdrive pulley is a good idea so long as it doesn't overdrive more than stock RPMs.

If you get a Katech tensioner, make sure you follow the torque specs, it's not much. If you over torque, you risk the bearings in all your accessories. Ask me how I know...

The alt IS a little low and **** happens. I got mine done at a GM dealer so I got lifetime parts AND labor warranty. Almost like I planned it...

If I lose one more, an AlterStart HO is going in. They really do solve problems, but try the other stuff first unless you do big stereos.