there’s definitely differences. The alternator itself is decently larger. It’s also a 6 phase hairpin which produces more power at idle than a standard alternator like a stock one. The smaller diameter pulley isn’t very much of a change, the belt you have to use is only 1/2 inch shorter. It definitely helps the output, but you wouldn’t get the same results if you just threw a smaller diameter pulley on a stock alternator lol

 

yea I was pretty happy. It’s nothing to swap out a pulley. I opted for a high output alt over a dual battery setup. I use the winch a lot in the winter to pull people out of the side of the road, $20 rather than waiting for AAA lol. Since it’s a 6 phase hairpin it produces a lot more power at idle than the stock one does, so I shouldn’t have to worry about draining the battery with multiple frequent uses. Plus my lights. I’m going with an Interstate ultra premium AGM battery come fall, I don’t think the factory one will last through another winter. I’ve never been sold on Optimas or any of those fancy ones, a good old interstate is good enough for me lol.

 

Belt length doesn’t make any difference, but a smaller pulley increases alternator speed at idle and on up to a point where the voltage regulator holds it from overcharging, back in the pre computer days we used to do a lot with pulley size, from alternators, power steering with larger tires helped a lot at low speeds, I’m sure they do more internally, but pulley size can do a lot for low engine rpm and higher output on alternator

https://alternatorparts.com/alternator-pulley-size.html

 

I’m saying the pulley isn’t that much smaller than stock. That’s why the belt is only 1/2 inch shorter. If it was a lot smaller than stock the belt would be 3/4-1 inch shorter. When I compared the two the pulley was only slightly smaller in diameter. When I get the new pulley and have everything out again I’ll post a side by side

 

This link gives you a better way to play with the numbers, just saying the crank pulley is 8 inches and the alternator is 2 inches, at 1000 rpm engine speed, the alternator is spinning 4000 rpm, a quarter of an inch smaller pulley on the alternator changes the speed to 4571 rpm, that 571 increase at 1000 rpm.

just an example, a small size difference can make a good difference.
not saying anything against the alternator company or what they produce or their customer service, just saying that the smaller pulley helps on what the overall product does and we used to play around with different pulley sizes that can make a difference

https://www.blocklayer.com/pulley-belteng.aspx