Underdrive vs lightweight crank pulley? is one better than the other? will they see the same results? I know lightweight keep the same diameter as stock, is it better to do this then move to under drive? does it matter?

 

an underdrive pulley will be smaller in diameter and will underdrive your accessories.
everything that is connected to that pulley will be under driven. this is bad. you dont want your components to be under driven.
it does exactly what the name implies....slows down everything that is connected to it.


the stock diameter light weight pulley has all the benefits of a smaller diameter pulley without the cons.

 

Not all... Obviously the under drive will spin the accessories less at all revs and thus u loose less power cause u are spinning ur accessories less.

The under drive makes more power.... But not much

Most of the power gained is from weight loss at the crank. And that couple extra ponies u get for under driving ur accessories is IMHO nor worth it.

This is coming from a guy who has an under drive pulley on his car right now for the last 4 years.

When u have all ur lights, rear defroster, seat warmers and fan on, u can see the power just get sucked away. As I have a volt meter

In the beginning it does not seem that bad, then ur battery will not be able to hold a charge and when u come to a stop u will see the battery is barely able to store a charge.

 

I have never had a issue with the light weight underdrive pulley. The biggest issue comes from the electrical system if you have a large system. I have around 700w and havent had a issue in 500k or so miles of running it

 

Good God, how many miles are on your car???

 

Thanks for the responses! what would be reliable brands for both?

 

i think he has about 500k or 600k.
not on original tranny tho.
he six speed swapped it.
and his current engine is a bit different than stock

 

Most of the gains are from the lighter weight and not the underdrive. The underdrive might add 1 hp over the stock diameter lightweight crank pulley.

 

All I know is I definitely felt a boost after I had mine installed. If you're really worried about electrical component holding up there are remedies (upgraded alternator, replacing all pulleys is supposed to compensate for the underdrive, but I don't know if it's been proven)

The only issue for me is just that it takes about 2 whole seconds for the headlights to reach full brightness when I turn them on.

 

So I know for an under drive pulley that I need to change out the belts. Do you have to with a light weight, because it the same diameter?

 

You do not for the lightweight. They're the same size as the factory pulley and use the same belt.

 

I'll be honest I felt more of a difference with the under drive pulley than the injen cold air intake.

Intake was my first mod, pulley was second.

Then I went for headers.... Oooooweeeeee. That was the day my car became. Beast. When u pull the old exhaust manifolds off and compare them it's a joke. Even a child could see how much better the headers flow is compared to stock.

 

i have an underdrive. if i had to do it again, i would prob go stock size, simply to keep the belts the same. not much dif with an underdrive. and if you ever want to go S/C, you'll need to get the reg size pulley anyway.

 

As long as you get that brick of a stock pulley out of there, you're good

 

So there is that much of a noticeable difference in response if I can get something lighter in there?

 

Ya, the revs seem to fly up.

 

Yea when u put the car in neutral and rev it ....it's rediculous the difference.