Had these pulleys for less than a week and this alternator pulley is pissing me off.I need to shift in to neutral and give it gas when im at a light at night with headlights/radio/defroster on and stuff.It happens when none of thats stuff is even on! I dont have an outrageous stereo or anything high output bulbs.I knew I should have just bought the crank pulley.Anyone want a underdrive alternator pulley? PM ME with an offer.

 

should have read my post. I repeat that regularly on here.

 

 

my lights dim with just the underdrive crank pully but that's cause I got a system.

 

Surprising these Fbody eat LOTS OF NECESSARY JUICE.
TODAYS CAR all seem to.
I'd only suggest another method for trying to gain some power. Unless your car really and often hits the strips.

 

I learnt the lesson about the alt pully it caused me to need many jump starts. Loose the alt pully and keep the crank one and you will be good to go.

 

Even with just the crank pulley on now.I notice major voltage drop at a long light or a "left turn signal" light or when stuck in major traffic.My car idles like at 600 RPM when its warmed up and full charge is suppose to be 900 RPM.

 

Mine does that too it hang at about 10 volts until i accelerate. You have to remeber there is less rotating mass with the smaller crank pully but all and all it will not cause any problems but i did opt to get a 160 amp alternator after i did that but it still hangs around 10 volts but no dimming.

 

i haven't had any problems so far, figure how long does it take to put the 5mins max juice drained at a light back into the battery when driving at 1500 rpms roughly?

 

After lots of testing, The best combo I came up with is using the ASP crank pulley only with a 140amp alt with idle at 850 range. I can run the headlights and radio at night sitting at a trafficlight without any drain at all or dimming. 800 rpms still had just a slight progressive dimming.

This is a Powermaster TPI 140amp alt with a homemade aluminum bracket.

 

Why would they make an alternator underdrive pulley?

How about an AC or Air pump underdrive pulley....Something not as important....

 

I have no clue, but it doesn't work as ASP claims. I even tried the ASP alt underdrive pulley with a 200amp alt. It was still discharging at idle and the amount of force the magnictic field generated by the 200amp alt to turn it robbed what HP I was trying to gain from underdriving it with the smaller pulley.

The thing that robs the most power is the waterpump. Hence whay I am going to an electric remote unit.

 

They make 3 piece kits with WP Pulleys for like every car except for the 3.1 V6....

 

the alternator underdrive pully is for drag cars if I'm not mistaken. Cars that don't really have anything electrical running cept for what's needed for the engine to run.

 

Never heard of that, seeing as that an alternator that is full-fielding all the time because you aren't charging right takes an AMAZING amount of power to turn.

The problem with new cars is that they put an alternator in that is just barley bigger that you absolutly NEED to run the vehicle. it cuts down on cost. They don't expect people like us to go messing with stuff and pulling a bigger drain on the electrical system.

 

When you are driving at night with "everything" on then yes it will be restricting much more due to a larger magnitic feild to produce the juice. But during normal operating times especially if you are racing the car during the day with nothing more than the ECM and ignition to run, the car Alt will not be pulling that much HP away from the motor.
Matter of fact, you could disconect it and "almost" run an entire 10 lap race on a road course with just the juice reserve from the battery.

But with all things equal, the Alt is never robbing as much power as it takes to turn the waterpump impellor wihich HAS to constantly turn and greater the force rises and HP lose the greater the rpms.

The problem with turning an Alt is the rpms needed to spin the alt fast enough to charge. I have tried using a Moroso elec waterpump drive kit to turn a 100amp alt and it will do it and maintain itself, however, the juice needed to get it wound up to rpms in order for it to maintain itself robs the battery enough that the high gearing needed to turn it is too much for it to independantly power up to the needed rpms- in other word, it needs help until until it is spinning are the proper rpms AND the battery is charge enough, then the magnetic field is low enough to just maintain the constant run.

 

hmm...that's interesting, I guess you learn something new everyday, huh? Never really thought about the water pump as being a drain on the engine, since you can turn it with your hands, but hey, I guess it could happen.