AAK z28

iTrader: (18)

can u just use the crank underdrive pulley and stock alternator pulley? will it make any difference?

Formula350

iTrader: (3)

Yep. But you'd be better off doing the belt-delete mod and save your money Much more power gained from it, and !BELT is a free-mod anyways.

monster81

if u use the stock alt pully with a smaller underdrive pully, ur alternator will be charching much less, ur voltage gauge will drop down and the battery will die very soon

96capricemgr

iTrader: (1)

Maybe with a stock engine but his mod list looks to include heads and cam which would result in a raised idle, eliminating any charging issues.

UD pullies are not particularly worthwhile, you get like .1 from pulling the belt, if the pullies are 34%ud it stands to reason maximum gain is .034.

koolaid_kid

iTrader: (21)

I ran the crank pulley w/o the alternator pulley for about 15k miles. Then one night, I was at the track, in line for my next race. Some dodo brain dropped his tranny in the middle of the track. By the time they had cleaned the track off, my battery had discharged (I was sitting there idling). I put the alternator pulley on and have not had a single problem since then. And the voltage on our inaccurate in-dash gauge is higher now as well (duh).

shutzero

which alternator pulley did you get

koolaid_kid

iTrader: (21)

I purchased ASP 847600 underdrive pulley for the crank, ASP 520004 overdrive pulley for the alternator, and a Gates belt.

Just remember, if you change the pulley now, you will have to change your belt as well because the alternator underdrive pulley is smaller in diameter than your stock pulley.

1redta

I put the asp pulley on the crank only and have had no problems with anything charging wise for 30,000 miles. LT1 altenators are 140 amps that's pretty beefy. do a big 3 upgrade first if you are that worried

want297z

iTrader: (7)

I never have put on the alternator pulley and ran 80k in a 6 speed and over 100k in an auto. It can be done and I have never had a problem with the batteries giving out early. If you are worried about it spinning too slow at idle, have the idle bumped up a few 100 rpm.

Formula350

iTrader: (3)

I think the cost of (via tune and not screw) of having the idle bumped up, unless you know someone with a tuner, vs buying the Alt pulley is pretty significant.


A non-********, serious, response by me to the OP: If you do a lot of stop-and-go driving, or have a sound system (I'd say even the Monsoon 10spk might be enough) then I'd get the Alt pulley as well, just to play it safe.

shutzero

I have the bbk underdrive pulley and get low idle rpms...its starting to effect charge pretty bad, just tryin to figure out what alternator pulley to get

96capricemgr

iTrader: (1)

Just take the UD crank pulley off, that is free.

wrd1972

iTrader: (12)

I have the ASP single crank pulley and 2000 watts in the trunk. Never a charging problem. Never a dead battery outside of sitting for months on end.

96capricemgr

iTrader: (1)

Again covered by raised idle from the cam programming.

evilbeef54

iTrader: (2)

could you explain what this is? And if i need to bump up idle rpm or something thats fine, i have tunercat, thanks

shutzero

I'm not gettting a cam installed for a few months, would it hurt to bump up the rpms without the cam?

Formula350

iTrader: (3)

Well, that belt delete MOD is where you take your belt off the car You can bump the idle up to 10^284e RPMs and it's not going to charge the battery with the belt off lol It was a joke really, but it's a quick trick you can do at the track to get a few extra horse for LITERALLY free. Just put it back on after your run.

evilbeef54

iTrader: (2)

lol, okay, i walked right into that one, lol

shutzero

would i be able to get just this pulley ASP 520004 run it with the bbk pulley to get the full charge? and what belt size would i need if this would work

ScreaminRedZ

iTrader: (3)

I would go with the alternator pulley as well. Why risk the charging issues.