Im looking for a pulley.. I came across some underdrive pulleys (ebay knockoff), some slighly oversized pulleys (xtune), and then some lightweight stock size ones. What are the difference between.... oversize, undersize, and stock lightw weight? There all light weight but what about the size? Thanks.
oversize means bigger than stock
undersize is smaller than stock
Im a Xbox 360 fanboy...and damn proud of it!!
If all of the pulleys are the same weight...
1. Undersize pulley will underdrive your AC, alternator, Supercharger, etc...which means it turns them slower than stock speed. The undersize pulley also benefits from less rotational inertia, because the mass is located closer to the center of rotation.
2. Oversize pulley will overdrive your AC, alternator, Supercharger, etc...which means it turns them faster than stock speed. This pulley will suffer from more rotational inertia due to more mass farther away from the center of rotation.
3. Stock pulley...I don't think that needs to be explained
Even though an oversize pulley has more rotational inertia than an underdrive pulley of the same weight, most of these pulleys are made of aluminum and the benefit of less rotational inertia is practically immeasurable.
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"Youth in Asia"...I don't see anything wrong with that.
thanks... Im going for the stock or undersized. Will I need a new belt for the over size one? Or does the tensioner free up?
To my knowledge
no one sells an overdriven crank pulley. AEM is the only on that sells an overdriven alternator pulley. The AEM pulley was designed to be used with the Unorthodox underdriven pulley. This is to keep the alternator spinning at about the same speed as stock. Try to stay away from OLD OLD OLD AEM pulleys, because it will not fit some new alternators.
Z-Spec and I are the only ones that make a
STOCK sized lightweight crank and alternator pulley. Also all the eBay pulleys are under driven crank pulleys.
Mastin did a quasi write up on his opinion on all the pulleys. He bought one from everyone, and picked the one he liked best. He would be a good source of knowledge on all thats out there. He tired to be 100% straight and upfront on quality form, fit, and function.
If you go over sized or under sized you will need a new belt.... unless you go with and AEM alternator pulley and Unorthodox underdriven crank pulley, then I believe a stock belt will work. It should go with out saying.... a stock sized pulleys will require a stock belt.
Also any pulley besides your stock pulley will give you a gain in horsepower. As long as it is lighter than stock, which all pulleys being manufactured are.
Also some people complain about idle with heavily under driven pulleys. Also a stereo can be to much for the alternator and battery is some cases.
Overdriven is only wanted for supercharged applications, but again I do not think any are made. "Yet"
I think that cover most of everything.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
