Overdrive alternator pulley

[kennythewelder]

Anybody running one of these. Since I installed my electric fans, at idle, with lights, AC, or defrost, on, when the fans kick on, the voltage drops low. I did the big 3 ,or in my case the big 5, ( extra grounds) and that does very good at say 1000 RPMs plus, but at idle the voltage drops low. Around 10 on the OE gauge. So I noticed this morning that just putting the truck in P, the volts came up from about 10, to about 11.5 ish soy thoughts, a small pulley should do the trick. So I was wondering who has experience with an overdrive pulley.

 

[Dropped88]

Sub'd im interested in this

 

[618 Syndicate]

Wouldn't a higher amperage alternator solve it?

 

[Supercharged111]

Wouldn't a higher amperage alternator solve it?

That's what I'd do, a Burb alternator should get it done. If he has the newer black box he may be able to command more from it down low too.

 

[kennythewelder]

Wouldn't a higher amperage alternator solve it?

Not really from my research. It may help, but the high amp alts, put out high amps at higher RPMs. At low RPMs they don't put out a lot more than OE alts. By replacing the OE pulley with a smaller pulley, this makes the alt turn faster. So you get better out put a lower RPMs. The OE 105 does fine at say above 1000 RPMs, but at idle, it goes low with the electric fans, and other options on. I want, need it to do better at idle. It really hasn't been a real issue, because I don't spend a lot of time at idle, so it hasn't been a real issue,,,,but,,,,.

 

[618 Syndicate]

I get what you're saying, but I still think a higher output alternator would out out more power at lower rpm as well.

 

[kennythewelder]

I get what you're saying, but I still think a higher output alternator would out out more power at lower rpm as well.

I hate to spend $150-$200 on a HO alt and it still doesn't do what I need. A small pulley runs from about $20 to about $60, or so. For some time now, I though about getting a HO alt from the junk yard, but I do like the idea of changing the pulley to a smaller one. I was just wondering if anyone has done the mod.

 

[454cid]

The AD244 is supposed to put out more down low. I think the CS144 does to an extent, but I have no idea how it compares to a CS130D. I think that as long as a modest bump is expected, an over drive would be a very cheap, and easy solution.... I bet a smaller belt would be the biggest cost, if that would even be needed.

I got the opportunity to work on alternators this past fall, becasue of my 69 Electra. It was actually kind of fun. I had no idea how easy it was to zip off the pulley with an impact. They were older designs, but I can't image the pulleys being any more difficult. I re-used stock pulleys for what I was doing.

 

[studigggs]

Anybody running one of these. Since I installed my electric fans, at idle, with lights, AC, or defrost, on, when the fans kick on, the voltage drops low. I did the big 3 ,or in my case the big 5, ( extra grounds) and that does very good at say 1000 RPMs plus, but at idle the voltage drops low. Around 10 on the OE gauge. So I noticed this morning that just putting the truck in P, the volts came up from about 10, to about 11.5 ish soy thoughts, a small pulley should do the trick. So I was wondering who has experience with an overdrive pulley.

Any way you can get an amp clamp around your fans and determine what they are pulling? This info may better guide you. For example, I just put an Autozone alt in last weekend and while testing was surprised to see 50A production at idle with high blower fan, high beams and thermal 4wd actuator engaged. My battery was only accepting 3A, so 47A of loads. I would imagine you are close to 100A with the loads you describe.

 

[RichLo]

No side-by-side experience but when I put a 200amp alt in my 93 I needed a smaller belt because the pulley was an overdrive pulley straight from the manufacturer. Just a thought that they might be on to something. Compensating for less output down low by over driving it.

It would be interesting to see your results Kenny! My dually drops slightly below 1000rpm also and that would be a cheap modification to help the charging system.