I just swapped my ZPI V2 pulley for a UR pulley Friday. It was on my car for about 6000 miles and this is what it looks like:



Are those groves on the neck bad? They weren't on there when I installed the pulley and I double and triple checked it when I screwed it down. Did it cause damage to my motor?

 

If one of these suckers caused damage to your engine, you'd definitely know it. I'm fairly sure you're in the clear for now. I don't know what to say about those grooves.

 

when you took out your stock pulley you should of seen the same groves. the pulley looks 100% fine

 

now tell me...is it a noticeable difference in power over stock?

 

I just found a pic of the old stock pulley and the ZPI before I installed it:



I can see the stock pulley has the groves, but what causes them?

There is def. a difference in the way the car runs with the lightweight pulley. I wouldn't say it's "faster" but more freed up. Engine seems to wind up faster and run smoother. I feel like my car is running a little better with the UR pulley.

 

The pulley's fine.

Pulleys do make your car faster... it doesn't add horsepower per-se, but it does lessen the difference between your crank hp and wheel hp.

 

They in NO way lessen the difference between your BHP and WHP. They seem to on an inertial dyno due to an inherent flaw in the way inertial dynos measuer torque and hp. It is against all laws of physics for them to affect wheel horsepower. An inertial dyno measures the time taken for a car to accellerate a load from one rpm to another. Even changing wheels on the car will fool the dyno into thinking the power output changed, which is does not. The correction factors used in these dynos are not completely accurate either. The only somewhat true measure of the power being output by a car is a steady state pull on a load bearing dyno. The pulley allows your engine to rev (and slow down) a little quicker, but the power being applied to the wheels is the same regardless. DynoJets (inertial dynos) are famous among tuners because they make mods like this to appear to make power where they do not. As a matter of fact, when the engine is at a steady state rpm, the lighter pulley makes it EASIER to slow down the engine. so there are tradeoffs even there. Out of all the people I have asked, NONE have come forward and posted times with and without the pulley other than one, a few days ago on ystc. He had better times the first time at the track, and worse than stock the next time.. so no percievable difference. He also developed an oil leak in the area near his front seal, not sure yet why.. but not the best of signs. Needless to say, no peformance gain on the track and a strange issue, so the pulley came off for him. The quicker revving will help you on the track a bit.. but the TINY effect of such a small amount of weight removed from such a small diameter will not be that noticeable time wise, especially since the same effect is negative as far as launching is concerned. A lighter flywheel will have much more effect in this area.

 

And you can take that to the bank.

 

Ok good. I'm putting this pulley up for sale then

 

Oh and read this

http://www.yoursciontc.com/forums/in...erdrive+pulley

 

After reading this info... I think I'm going to get rid of the UR pulley and switch back to stock. It's not worth the risk of severe engine damage. Thanks!

 

I wasn't trying to scare you. I have a UR pulley on my car right now (not a tC) and it's been there for about 2.5 years (35K miles) and I haven't seen any problems. Personally it was a wasted mod. The only reason I never took it off is because the stock pulley was chipped up real bad and I found a hair line crack in it. So I was kinda stuck.

 

Quickly everyone, take your pulleys off your cars now!!!

This just in from the FDA: Aside from being a complete waste of money, time, and effort, pulleys have been rumored to cause cancer, rattle teeth fillings out of senior citizens' mouths, cause ***** shrinkage, and will most certainly lead to your girlfriends dumping you. I found this on the internet. It is fact!

http://www.thenorthamericanfoundatio...ndresearch.com

 

First off, the link that Josh gave you is a summary for stuff written by people who know. Notably, Steve Dinan. A guy who's been tuning BMWs for longer than a lot of people here have been driving.

Secondly, you don't feel the vibrations that Lo_bux is talking about.

Thirdly, why is everyone so against learning something? The mantra for turbocharging is, "know what you're getting into before you turbo." Well, damn, know what you're getting into before swapping for a solid pulley.



My opinion of pulleys: they're like Bud Light. You can drink one bottle, not feel a thing. You can drink two, not feel a thing. You could drink four or five or forty five and not feel a thing but sooner or later, you're probably going to throw up. Science just supports it. How many people have thrown up because of a few Bud Lights? Not too many, I don't think.

But know what you're getting into and read Dinan's paper. It's more to the point.

 

LMAO!!

 

Crank pullies are JUNK, save for a flywheel.

 

Yeah, too many people are focused on arguing to the point that they dont even read the information, and keep arguing the same points that dont apply.. like the issues being balancing or car vibrations. That has been thoroughly explained, but those supporting the pulleys will not read what is being printed for them. Those links also point to toyota material, so this is not made up. I am the first to say that any power mod in some way will reduce engine life, but a "power" mod like this, that produces zero power and can cause some very serious and difficult to trace issues is in no way a good mod imo. You get an engine that revs SLIGHTLY quicker than stock, that is it. No power to be had. And the fact that no one will ever post up before and after times for this magical mod is somewhat funny as well. And the one person that did admitted it did practically nothing except caused a potential issue and took it off thier car.

As far as power, do some searching on inertial vs load based dynos and see what you find. The info regarding inaccuracies in the inertial systems DIRECTLY relates to the power measured when using a lightweight pulley.

Honestly, it isnt on my car, so I dont have to worry. I will still run just as fast and not worry. I just hate half stated or incorrect information being put out there by people trying to sell a part. There are too many people modding without a clue of what they are doing. Some of us just try to post information to change that. It makes the enthusiast culture better as a whole when more people know what they are doing and make better decisions. It drives higher quality parts and makes people expect more out of the tuner shops than a bunch of kids that know very little. So people shouldnt attack us for saying the pulley is not a sound and worthwhile mod. Attack the physics, science and general experience of the info posted and THEN we can argue about something. So far it has been one side posting solid, scientific and automotive facts against dumb comments making fun of those facts. The credibility from any standpoint isnt exactly going to lie with the dumb comment people now is it? Its like one person explaining escape velocities to a wannabe astronaut and the wannabe replying "yeah but your stupid looking". Not exactly a valid argument.

 

Mythbusters should do an episode on crank pulleys.

Take a sample group of completely stock motors with stock crank pulleys.

Take another completely stock sample group with aftermarket crank pulleys.

See which of those have problems first. THAT would be solid, concrete, and more applicable evidence.

Until a reputable research group can do this everything else is heresay, theoretical, and text book formulas. And we have all heard the old saying, "those who CAN, do. Those who CAN NOT, go and teach"

I will take my personal experience with what I have learned through my own personal experience over the words of someone writing something on the internet anyday.

Best of luck to us all

 

Wow... so dinan, toyota, ATI, etc dont have the experience you want, but a couple of special effects people running a one day test do? That is hilarious and a token of great thinking What is mythbusters going to do... run a 5 year special to see which ones fail? Then try to determine the causes? Funny. how about the examples of supra owners over on ystc that were mentioned that had catastrophic crank failure? Or the simple fact that the people who designed yoru engine (and EVERY engine other than the handfull designed not to run dampers) designed for it because they deemed it a needed item? But hey... your anectdotal and short lived "real life results" are much more sound than any of that Not to mention the mod ADDS NO POWER at all, which is in no way arguable to anyone posessing a high school level of physics. We can differ in opinion, but trying to base the little you have above saying that the sources we have given are not reputable and knowledgeable? That is comical.