[greentrees]

I've read for about an hour on these forums and find conflicting info - please chime in if you can help me with this.

I'm about to buy the NST crank pulley and belt, I'm wondering if the alternator pulley is necessary or not. Some say YES, as it helps compensate for losses from the crank pulley. Some say NO, it's only necessary if you have an aftermarket stereo system.

I realize that the crank pulley brings the real gain here, just wondering if the alt pulley is even really necessary if I'm sticking with OEM stereo.

Any perspectives would be helpful, thanks much.

-- Jeff

 

[CalgaryTSX]

The 1st step to your question is to compare crankshaft pulley diameters:

Stock TSX K24 crank pulley ------ 6.125"
NST crank pulley ----------------- 5.2"
UR crank pulley ------------------ 5.125"
K20Z1 RSX-S PRC crank pulley ---- 5.4"


I added the RSX-S crank pulley because I have been running that one with the stock alternator pulley for over 2 years.
Watching the battery voltage closely, our TSX does charge slightly less at idle but it's been totally fine.
The car still has the original Acura battery & we do get cold winters up here.

Since the NST crank pulley is only very slightly less in diameter, I'm sure you will be fine.
While the UR crank pulley is slightly smaller in diameter it does include a smaller diameter alternator pulley restoring some of the alternator rpm's.

Another pointer would be to make sure your new serpentine belt is slightly on the shorter side according to the tensioner marks.
Especially when the belt is brand new.

 

[greentrees]

Thanks for the info I appreciate it!

I think I'm gonna go with just the crank pulley. My Honda mech will do that and the belt for $69. I found a bunch of info on another site last night, there were bunches of people doing just the crank pulley back in 2006-2007 before the alt pulleys were an option. Most of them did fine, the only issues were belt length. NST offers the corresponding belt to go with the underdriven crank pulley so I feel like it'll be OK.

Anyone else feel free to chime in...

 

[greentrees]

Any more opinions or experience with this?

 

[bluecarbonfiber]

i had the nst crank pulley (still do laying in my shop) and the alt pulley at the same time the alt pulley is still lighter then stock which also helps the driving force.. I now run the Ralco Rz Pulleys (tsx stock diameter)with the NST Alt pulley and like it just as much.. honestly cant tell much of a difference when i swapped out the crank pulleys but the charge is a constant 14.4v at idle and throttle varies between 14 and 14.2v (im guessing electronics being used) start ups seem alittle easier.. (could be in my head) but if you are just looking for lighter pulleys for the HP i would suggest the ralco RZ or the unorthodox stock diameter kits.. you still get pretty much the same results with maybe a 1-2 hp loss due to the underdrive not being there..