Thinking of getting u/d pulleys... questions

I'm also running only the crank and water pump pulleys. The factory alt. pulley is just a hair smaller diamerter than the underdrive unit (IIRC), and mine just barely charges at idle, so long as the headlights are not on. I bought an overdrive alternator pulley, but I have been too lazy to put it on. The charging problem varies from car to car and from brand to brand.
 
http://www.aspracing.com

Search under "Ford, Mustang/Capri", and they are at the very bottom of the page.
Part # ASP520004
1-7/8" overdrive alternator pulley - $19.99

I ordered it on a monday and received it on the thursday that same week. A+ :nice:

I installed it but none of the parts stores around here had the proper length belt for it to work, so I had to put the stock one back on. You'll need a belt approx. 1/2" shorter than stock, and for some reason they are hard to find, at least where I live :bang:
 
Honestly Guys

When the alt pulley is not used, you are not getting the full benefit of the mod.

After all ... the mod is a small gain benefit at its very best.

Unless you got a mega sound system that pulls a bunch of power

The dimming lights at idle for the length of a stop light is not gonna hurt you any.

Grady
 
When you put the alternator pulley on, you'll find out quickly how well your charging system is putting out.

I had some crazy voltage drops w/ all accessories on - enough to stall the car and make the speakers pop.

An alternator and ground wiring upgrade later and things are great - little to no dimming.
 
final5-0 said:
Honestly Guys

When the alt pulley is not used, you are not getting the full benefit of the mod.

After all ... the mod is a small gain benefit at its very best.

Unless you got a mega sound system that pulls a bunch of power

The dimming lights at idle for the length of a stop light is not gonna hurt you any.

Grady

i get what you mean, but what about when you're stuck in traffic. I have found that I have to step on the gas and idle it at 1300rpm in order for my battery not to die and then not want to start. Happened once before.:bang:
 
Stanger007 said:
When you put the alternator pulley on, you'll find out quickly how well your charging system is putting out.

I had some crazy voltage drops w/ all accessories on - enough to stall the car and make the speakers pop.

An alternator and ground wiring upgrade later and things are great - little to no dimming.

Your post made me remember something :D

I keep forgetting I idle at 850 to 900 rpm :bang:

Those of you who still run the stock cam and can idle around 650 will see more dimming at stop lights at night.

At the stock rpm ... just 100 more can really make a diff in juice output from the alt :D

Just wanted to point that out and didn't wanna mislead anyone :)

Grady
 
I'm another who thinks UD's kinda suck (living in an extreme climate means my water pump and alt get a work out though).

The benefits dont really come till higher Revs, and a DD probably doesnt see much time there (but does at idle).
 
HISSIN50 said:
The benefits dont really come till higher Revs, and a DD probably doesnt see much time there (but does at idle).

I agree, I'm sure they are doing more harm than good since mine is a DD, they were on the car when I bought it. If I had the old stock pullies at hand, I'd swap them back on.
 
About the gain from pulleys :D

Most of the talk I've seen is all about WOT only, whether it be dyno or 1/4 mile.

I have seen most say 1 to 1.5 of a tenth with rare examples reporting as much as 2 tenths lower 1/4 mile times.

On the dyno I have always felt they are worth about 5 to 10 and if the truth were known ... I bet the true value would be closer to 5 than 10.

Again ... if the complete set is not used ... I don't see how one could expect to reap the full gain possible.

On a side note ....................

Way back in the day of my youth :D

I used to have a toggle switch that would kill the generator (if you don't know what that is ... I'll let JT have the honors of splainin it :rlaugh: ) and that little mod was good for one full tenth lower 1/4 mile et.

The bottom line here is ..............
ANY voltage generating device does indeed use hp ;)

Grady