Cool looking paperweight I bet.....

 

Definitely.... the best conversation starter ever...

 

Seems like a trend to me. Buy stuff and leave it lying around.

 

can someone post pictures of there udp installed

 

Why? It looks like a reduced diameter crank pulley....

 

its not like you can really see it. go out to your car and try to take a peek at the crank pulley.

 

You should see my other "paperweights".... 6th Gen calipers, 5.5 upper and lower IM, VAFC-II, H-techs....

 

Been waiting to see where this goes.

In theory, if you can get going faster with the the tires off the ground (weight of car not being a factor) then you would have more foot pounds of torque would you not?

I've heard this from several people. I'm not denying your right, but it doesn't make sence why it would rev quicker w/o some sort of performance gain. I question if it's psychological and if your just buying the hype.
Incorrect.
http://www.cyberauto.com/index.php/unorthodox.htm .This is from a seller of Unorthodox products, so take there dyno results with a grain of salt.

Even Unorthodox and their sellers have conflicting info, if that tells you anythings.

IIRC, I beleive that depends if your crank is externally or internally balanced.
You where almost onto something here, until you got past your first sentence. How in the hell are you going to compare final drive gear ratios to accessary gear ratios and even begin to think your point is valid? Gear ratios directly effects the speed/torque of the tire. Accessory pulleys don't, not even indirectly.
You ever notice performance mags will do a intake swap and dyno before after? Or they will do an exhaust before/after dyno? Well I challenge you to look through as many performance mags as you can find and show me just ONE UNBIASED dyno with before/after dyno results with out ANY other mods or tuning done and of course on the same day with the exact same conditions.. Performance mags don't do this for 1 reason. They are advertisers and don't want to run them away. Yes, of course, you can pull before/after dyno results up all day that shoe an improvement. They're either 1.) A seller of such product. 2.)A sponsor of such company.. Or they dynoed on a different day with a potentially different atmospheric pressure, different tuning, different fuel, etc.
Here's the only unbiased info I could find.
http://www.teamscr.com/pulleys.htm

Also,Making any other pulley than the crank pulley lighter doesn't make any sence either...The bearings that rotate the pulley having less friction would play a larger factor than the pulley weight itself. Manufacturers spend billions every year making sure their accessories already operate at there most efficient and everything is created around that concept. One could assume even creating near frictionless bearings with stock pulleys would/could be a priority.


Without doing research on the history of UDPs, I would assume that was the selling point. As more and more people got smarter they may have changed there selling tactics.

 

you should see my paperweights... in addition to having a motostorm UDP sitting around since that GD, i've had ksports sitting around for months, and more used car audio than a flea market

 

50 posts and no one has dyno or track results...

 

That must be a good size desk. At least it's not going anywhere.

Wish I had that problem though, as my mods have been limited to my allowance the wifey gives me, which currently sits at $0. So yeah, basically foglight rewire and maybe stepping it up a notch to do the GAB conversion.

My guess is that noone has recently done this conversion...yet...for before and after results. *shrug

 

bpe383, thank you for posting a bunch of info I already know.

I can post quotes too!

"First, and most important, is the weight lose. An average of 2.7 HP is gained from every pound lost off the crank shaft. 85% of the gains are from weight loss. The rest of the gains are from underdriving which accounts for about 15% of the total gains."

Im not arguing with you about underdriving (yes, I know what the word means), but I totally disagree with your idea that gains arent made from weight reduction. UR also makes a stock diameter lightened pulley. So how does this increase efficiency if weight has negligible? You may not make that much power, but UD pulleys arent going to have fantastic gains either.

You want to get into flywheels next?

 

My Motostorm UDP...

 

I like my UDP, but saying that for every pound taken off the crank gives 2.7hp is unrealistic.... It really depends on the car, if that was the case I would have FELT the power difference when I installed it. The stock pully is REALLY heavy, the Motorsotrm one is easliy 1/3 the weight...

I still have the stock one sitting around upstate, the next time I am up there I will try and see the difference in them.

Puppet; if by chance you do install before I go back upstate can you throw the two on a scale?

 

Tell me about it. I did that for a while and just sold everything.

 

Probably due to driveline loss. Maybe they translate the gains to hp at the crank. Doubt if you would really be able the feel a 5whp difference in the first place. And yes, numbers are always going to be different between different cars.

 

What the he!! does this mean??????


Because driving these accessories at higher rpm is a waste of energy, running them at a much higher rate than it needs to for optimum effectiveness. This is energy which could be put toward acceleration instead. Not psychological or hype.


Quote:
Originally Posted by kcowden
I don't know what to tell you other than the word under drive means Dia. not weight. It it was all abou the weight then why call them UDP, why not light weight pulleys?

This wasnt even my quote..... make sure your double checking your work before handing it in.


"Each accessory uses rotary power - each accessory is turned to perform it's function, whether it's an electrical component (the alternator) or a fluid displacing component (the water pump and power steering pump). They all have a pulley which takes power from the crankshaft pulley via a belt.

Some of the engine accessories take more power than they really need, dramatically affecting engine performance.

Driving these accessories at higher rpm is a waste of energy, running them at a much higher rate than it needs to for optimum effectiveness. This is energy which could be put toward acceleration instead.

An underdrive pulley is a replacement accessory pulley that bolts up the same as stock, but has a different size (ratio) and material specifications intended to free up lost horsepower. By increasing the diameter of each accessory pulley, the speed at which the accessories are turning relative to engine RPM decreases.

Does this actually make horsepower?

Underdriving the accessories does not add power to the engine, it frees up the power that is normally wasted on overdriven accessories. The theory is that a larger pulley will drive the accessories slower thus reducing their parasitic horsepower loss. No more power total, but more power sent to the wheels. As an additional benefit, the reduction in wear (less usage) on the accessories due to the lower duty cycles can extend the life of these parts."

 

You guys should spend your energy and time on something a little bit more useful rather than a pulley.

 

I only put mine on since I could pick one up for $75 shipped and I had to replace my belts anyway... I figured it could not hurt, I would never spend $200+ on other ones or go way out of my way to replace it.

 

I wasn't referrig to you.. But moreso the guys with paragraph after paragraph of .

 

I'll let ya know if I get to that.... or anything else for that matter.

 

The neverending debate just keeps going on doesn't it?

 

Well said.....

 

F'ing A Cotton, F'ing A...