I cant remember if I posted this earlier, but I am sorta interested in this overdrive pulley for the alternator.
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Our trucks dont rev very high compared to gas engines, basically half as much, and I figured that if an alternator can spin 6k on a modular, why cant it spin more then 3k on a diesel.
I use a winch a lot, and I have the ford idle control module to help keep the batteries charged (works awesome by the way) I was wondering others opinions on using this pulley. Im sure it does not overdrive it by much, but any is better then nothing I figured. It will help with most all other applications like lots of lights or accessories, where you cant use the idle controller (need to be in park or neutral and parking brake set)

Any opinions. Ill be getting a bigger alternator as soon as the one on the truck dies....which who knows when that is, but until then, what do you think.

 

I don't know about that pully, but if the alt is putting out 14.7 volts, I don't think it matters how fast it spins.

 

well volts and amps are somewhat related due to wattage and such, but you can be drawing more amps then the alt is putting out at the 14.x volts, and then the batteries are being used, and not the alternator. Spinning the alt faster I would assume will get the alternator more into its "sweet spot" (because at low rpm it puts out less amps then at a higher rpm, to a point) and keep the batteries maintained better. Im not an electrical person so Im not sure...

 

They are great for Increasing the amperage at idle. I would think its a worthwhile investment for what your using the truck for.
Basically a high idle will give you the same results.

 

Like I said, I don't know either. Heck, get one and give it a try and let us know how it works. Are our alts different from the gas engine?

 

I thought they were the same as the 140amp gas alt, just "derated" basically because the rpm limit of the psd didnt allow the alt to get up in rpm like the gas. BUT if the crank pully of the psd was large enough, then that would make 3k on the diesel seem like 6k on the gas, but I doubt they did that cause the ps pump would take an abusing, seeing as though idle of the diesel and gas are about the same and so is cruising rpm.
I would still say that the alt is very similar, if not the same, ony different...sorta.
for 37 dollars, it isnt a bad investment i dont think, and you dont even need a new acessory belt thankfully, seeing as though i just replaced mine.

 

It should work.
Make sure that your belt tensioner is good and strong.
That smaller pulley will give some on the length of the belt and the tensioner will take up the slack.
Which will relax some of the spring pressure that the tensioner exerts against the belt.
Or you might have to find a slightly larger idler roller, or a slightly shorter belt.

 

Good thinking Dan...

 

Once again Kwik sees something I didnt think of,thanks

 

I use to overdrive my alternator on my service trucks years ago.It helped with cooling the alternator and gave more amperage at idle

 

Could he just put some shims under where the alt mounts?

 

I did that initially on my new large case alternator I installed this summer, but I ended up stripping a bolt and had to replace the bracket, at which time I ground the center down a bit so the new alt would sit proper and let me get full thread bite into the bracket to minimize potential for stripped threads again.

 

Kinda. It will support more current draw at faster RPMs though. But you're right -- if it's holding over 14V, then you're NOT drawing more from the batts...

Not really -- as the load increases, the Voltage will drop to battery voltage. At idle, I can watch mine drop lower & lower (from 14.2 to about 13.8) as I put the lights on, and turn the AC blower on high. If I had more high current stuff to load it down more, it would eventually drop to 12.5 V or so, then even lower as the batts discharge. If I drive off or switch to my high idle tune, the voltage returns to ~14.2...

 

That would work.
But see Pete's experience below and get some longer bolts.

Pete, I know it's too late now, but you can get a heli-coil thread repair kit with 10 heli-coils in it for less than $30.00 at Napa.
IIRC the thread is metric 10x1.5.
It will look similar to this, but I couldn't find a 10x1.5 kit online to provide a link.
Store Locator | NAPA Online

 

That's what I was thinking Kwik. BTW like what you have up there by your avatar, just wish I & the USA would listen a lot more.