Alternator pulley larger size?
It actually works backwards with a smaller crank pulley. The Moroso is smaller than the factory pulleys, thus slowing the alternator speed. I think my factory crank pulley was almost 7 inches. (makes a good wheel chalk now) I kept tossing the alternator belt at 7000 RPM. The moroso pulley helped my case a bunch. My alternator is a 140 amp aftermarket. haven't had idle charging issues since swapping to the moroso.
(FYI the moroso has a single offset bolt hole that won't lineup with some aftermarket balancers...so you may have to run one less bolt if you don't have the early type balancer with the one offset hole)
kinda off topic, but may help someone else in the future
So to pop this back to the top...my words above came prior to the install of a bolt on electric water pump. I had a little moroso add on pump fail, and went with a bolt on direct bolt on water pump.
Since that pump install I had been chasing low voltage and charging issues if the race day ran long. Threw a new monster powermaster alternator at it, and voltage regulator, no change. Installed a voltmeter, and realized that at anything under approx 1500 rpm, the little 5 inch crank pulley is not spinning my alternator quick enough to charge. I am only putting out 10 volts at "idle" so in my quest to not throw belts, I shot myself in the foot with idle charging.
Yesterday I had some labored starting, and hooked up my trucks jumper cables. I could actually HEAR my electric fan pick up NOTICABLE rpm.
My conclusion... the small moroso pulley is not the fix all I thought it was, and I am putting major strain on my electric accessories, and slowly discharging my battery even with the engine running.
Now the search begins for a larger crank pulley... or maybe a serpentine crank/alternator Pulley. And hoping my geometry is correct enough to not roll/toss belts
Wanted to post, although an old thread, to save someone the problems involved with this underdrive pulley BS
