N/A UPGRADE BIBLE.

[ewang9394]

Originally Posted by

Underdrive pulleys do just what the name says, they underdrive the alternator. the alternator doesn't turn as fast, so it doesn't generate as much power for a small hp gain. This is why your lights dim, they aren't getting as much power... Your lights should only dim at idle, however.

The problem is that they shorten the life of your engine, despite what uneducated enthusiasts say... if you don't believe me, read this:
http://dinancars.com/html/danger_of_power_pulleys.htm

Nuff said

Yes, my lights (especially head lights) are kinda dim during idle. Once I rev, the light goes back to normal. So I guess the pulley is harmful to the engine in the long run. But does it produce power in anyway??? I asked my mechanic and he said that it really does nothing in terms of power to the car. Any comments? I'm not familiar with the udp because it was intalled when I got the car.

Thanks,
Ed

[<T>]

Originally Posted by ewang9394

Yes, my lights (especially head lights) are kinda dim during idle. Once I rev, the light goes back to normal. So I guess the pulley is harmful to the engine in the long run. But does it produce power in anyway??? I asked my mechanic and he said that it really does nothing in terms of power to the car. Any comments? I'm not familiar with the udp because it was intalled when I got the car.

Thanks,
Ed

The 10-20hp claims are complete 100% bullshit-smoke-up-your-ass. 5-8hp if you're lucky! If you want such a little upgrade save yourself the cash and buy a good air filter...

I personally ran without a crank pulley (the ULTIMATE underdrive pulley) just for fun to see if there was any difference, and it was minimal at best... my butt would say about 5hp at most, honestly. It's as much a bullshit upgrade as plenum spacers or throttle body spacers... just a gimmick.

Bottom line, it isn't worth the risk for the small amount of hp you get... honestly I would say if you have a good amount of miles on the car I would look into getting a stock replacement crank pulley, but that's just me. Just know it is the equivalent of smoking cigarrettes... it aint gonna do harm right away, but over time it sure as hell will.

Hey if you'll buy a UDP or spacer, maybe you'll be interested in this!:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=2980180592

[t_do]

//austin power voice// why wont this thread die!

[chansigril]

i have an underdrive pulley (udp) currently installed, and have had it on my vehicle for the past 50k+ miles. i have *no* problems with my car, my crank, my belts or my electrical systems. the lights do dim at idle. i have no oil leaks. it does provide a boost in power. no one i know personally has had an issue with their udp... and that is a good many people, including contacts with tuner shops. for some real-life information about underdrive pulleys on our cars, visit this thread.

i want the tin foil hat too! it will protect me from fbi.com

- mike

[<T>]

Originally Posted by chansigril

i want the tin foil hat too! it will protect me from fbi.com

- mike

Umm... the entire source for that site is:


In other words it's blank... is that part of the joke?

[chansigril]

Originally Posted by

Umm... the entire source for that site is:


In other words it's blank... is that part of the joke?

if you check the ebay item it specifically lists that site as an entity which the hat will protect you from. i wanna know how T found that site but i digress... let's keep this a noob bible, meaningful discussion and all

- mike

[<T>]

Originally Posted by chansigril

if you check the ebay item it specifically lists that site as an entity which the hat will protect you from. i wanna know how T found that site

How'd I find the eBay item? It was in a forwarded email, but it has been featured on a bunch of "Who Would Buy That?" type sites... and there are a million sites like that out there too...

I do say that is genius though, check out his other items... he's selling I think a pizza crust in a peanut butter jar as one of his items lol

Originally Posted by chansigril

but i digress... let's keep this a noob bible, meaningful discussion and all

- mike

If it wasn't for us, this thread would be dead already, so I think no one will care if we poke the carcass

[LVA3KGT]

UDP are, in theory, bad for the life of your motor.
However... I have 178K miles on my motor. 118K of those are w/ the UDP. So far, so good. Gains are slight at best, and truth be told, I wouldn't waste the money on it again.
If anything, My K&N filter is what is bad for my car. Ever since I've had it, I've noticed my oil gets dirtier faster. I used to change it ~6K miles (mobile 1 oil and filter). Now I change it 3-4K miles. Now, I haven't taken the oil to be analized; it just looks black much faster than it used to... of course, I do have 178K miles on my motor...what do you expect? lol

[YOGURT!]

hey fellas, whats up.... GOD, this thread is like 3 years old, and has gotten over 15k views...... lol thats great! anyway. someone should go ahead and update this thing and clean it up a bit so they can make it a sticky........
glad to see im still helpin people out!


hey i disagree man, the UDP's are a good mod, its simple physics, less rotating mass=higher potential velocity? right? anyone who says the underdrive pulleys are going to break or potentially break your engine are full of it. if you have a 1200 hp motor then yes, the slight vibrations would magnify into bad things over TIME..... not in a car that puts 156 hp to the ground tho man... come on. common sense.

anyway. its cool to see this thread is up and around. lol good luck guys, i think im comin back to 3si, this time incarnated in TWIN TURBO form. the Z is too much of a problem child.

[<T>]

Man where the hell have you been?! Glad to have ya back

Anyways, the less rotating mass isn't even where most of the benefit comes from, but rather underdriving the components decreasing the load on the engine. The problem is not with either of these two functions (although underdriving your alternator shortens its life) but rather that a VITAL piece of engineering is being removed from the car, the harmonic balancer. Even a 2L 4 cylinder needs a tortional damper.

Besides all the risks, it has been shown on every independant dyno that UDP's are worthless as a power adder anyways, adding 1-3hp on everything from 4 cylinder hondas to 8 cylinder BMW's across the board. (an alternator is going to take just as much power to drive on a V10 as it will on an I4) Never mind the fact that in that same test four out of six BMW's equipped with UDP's needed rebuilt after a full weekend of racing.
http://www.teamscr.com/pulleys.htm
Here you can see they completely removed the accessory pulley and only saw a 3hp gain.

It's funny that if you claim certain horsepower figures over and over how people will just accept them. Just like the amazing Tornado was for a while until people actually took it to the dyno and found out it REDUCED hp because it is a restriction.

anyways, yeah good thread!