To all those with issues on Pulleys
Mar 10, 2004, 11:43 PM
#16
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Here is an independant test with an EVO showing a definiate 10 WHP gain, same day before and after.
https://www.evolutionm.net/forums/sh...ht=pulley+test
I guess the countless individuals who have used these pulley's for years and thousands of miles without a single problem just got lucky some how
The fact is there, is a very small minority of people who claim to have had problems due to an underdrive pulley. Not one of them has come forward with any real evidence or objective test data.
You want objective empherical test data that shows these pulley's are completely safe, proof!. How about some real evidence that it is not safe/reliable? The vast number of people who have reliably used them for a very long time without any reliability issues does not indicate anything to the nay sayers?
I am just baffled by those who argue so vehemently against these pulleys with no evidence and only half baked theories based on many assumptions.
There is also countless independent tests done on a variety of cars, the vast majority of these tests have shown 5-15WHP. Even out of the under drive pulley nay sayers, very few will deny the torque/power that can be freed up by them.
The Dynoflash knock sensor theory also has several holes in it, like why are other EVO's showing significant power increases with the pulley? His test methods and assumptions are highly suspect IMO. Of course that was also discussed in the threads that Tim referred too.
Tim, I would have bought your pulley if I did not already have one
.
https://www.evolutionm.net/forums/sh...ht=pulley+test
I guess the countless individuals who have used these pulley's for years and thousands of miles without a single problem just got lucky some how
The fact is there, is a very small minority of people who claim to have had problems due to an underdrive pulley. Not one of them has come forward with any real evidence or objective test data.
You want objective empherical test data that shows these pulley's are completely safe, proof!. How about some real evidence that it is not safe/reliable? The vast number of people who have reliably used them for a very long time without any reliability issues does not indicate anything to the nay sayers?
I am just baffled by those who argue so vehemently against these pulleys with no evidence and only half baked theories based on many assumptions.
There is also countless independent tests done on a variety of cars, the vast majority of these tests have shown 5-15WHP. Even out of the under drive pulley nay sayers, very few will deny the torque/power that can be freed up by them.
The Dynoflash knock sensor theory also has several holes in it, like why are other EVO's showing significant power increases with the pulley? His test methods and assumptions are highly suspect IMO. Of course that was also discussed in the threads that Tim referred too.
Tim, I would have bought your pulley if I did not already have one
.
Mar 11, 2004, 12:57 AM
#17
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so if you dont need a harmonic damper, why are the 8 second honda guys using fluidampers and not lightweight/underdrive pulleys? :-)
dont forget the engine vibrations go somewhere, if they arent absorbed by the crank pulley, they get absorbed elsewhere, like oil pumps or the flywheel for example.
with modern forged, or high strength pressure cast cranks i dont think the cranks will have much of a problem with the vibrations, they'll just pass them on to more voulnerable parts, which can lead to reliability issues.
The more horsepower you make, the stronger vibrations that are created, perhaps why some of the "older" 4 cylinders were able to get away without them?
im not trying to bash, its just been a topic that recently has been on my mind alot, and i could be wrong, but i've seen blown oil pumps from mild turbocharged setups in certain applications where people have had underdrive pulleys..
dont forget the engine vibrations go somewhere, if they arent absorbed by the crank pulley, they get absorbed elsewhere, like oil pumps or the flywheel for example.
with modern forged, or high strength pressure cast cranks i dont think the cranks will have much of a problem with the vibrations, they'll just pass them on to more voulnerable parts, which can lead to reliability issues.
The more horsepower you make, the stronger vibrations that are created, perhaps why some of the "older" 4 cylinders were able to get away without them?
im not trying to bash, its just been a topic that recently has been on my mind alot, and i could be wrong, but i've seen blown oil pumps from mild turbocharged setups in certain applications where people have had underdrive pulleys..
Last edited by lazerusmfh; Mar 11, 2004 at 01:13 AM.
Mar 11, 2004, 01:33 PM
#18
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so if you dont need a harmonic damper, why are the 8 second honda guys using fluidampers and not lightweight/underdrive pulleys? :-)
I have also heard the rumor that certain honda engines have experienced oil pump failures, and that some mechanics believe that it is some how related to an under drive pulley. But again, no one can say for sure what exactly caused the failure, and it seems to be limited to specific Honda engines. So oil pumps never fail? only on engines with after market pulley's, is that right? Not to mention that we are not talking about Hondas here.
dont forget the engine vibrations go somewhere, if they arent absorbed by the crank pulley, they get absorbed elsewhere, like oil pumps or the flywheel for example.
1. Just how destructive are these harmonic vibrations?
2. Does the stock pulley really do all that much to remove them? Is that even really what it is there for?
3. Wouldn't a light weight fly wheel/clutch have a similiar affect on crank shaft harmonics?
The fact is no one really knows because there has been no controlled objective testing done.
What we do know is that there are thousands of under drive pulley's out there running in a large variety of applications (many High HP), and the vast majority have experienced no engine failure or accessory damage. So what does that tell you?
The more horsepower you make, the stronger vibrations that are created, perhaps why some of the "older" 4 cylinders were able to get away without them?
Last edited by cowboy; Mar 11, 2004 at 08:05 PM.
Mar 11, 2004, 01:48 PM
#19
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I have the UR Pulley Kit on my Evo with what i believe have been no problems. I did allot of mods at once so i cant tell you how much was due to the pulleys. I do have a Auterra Data Logger and dont seem to be having any problems. If you guys can tell me what the stock values are maybe i can make a couple of runs with the data logger and post the numbers i get. Just let me know what data you would like to see and what the stock values are compared to mine and we can go from there. 
Chris
Chris
Mar 11, 2004, 02:06 PM
#21
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Hey cowboy, my post wasnt to be an *** like you are, so dont act like one towards me, please.
Im just stating that most of the fastest four cylinders around are using fluidampers, and they're must be a very good reason as to why they do, otherwise people would all have underdrive pulleys!
Dont take me for an idiot, im about finding the facts and information.
You did post some very valid questions, maybe someone has some answers with some concrete evidence?
Thats pretty cool your aproach to replying to my post though, shows you're a real nice guy and looking for concrete information.
Brad
Im just stating that most of the fastest four cylinders around are using fluidampers, and they're must be a very good reason as to why they do, otherwise people would all have underdrive pulleys!
Dont take me for an idiot, im about finding the facts and information.
You did post some very valid questions, maybe someone has some answers with some concrete evidence?
Thats pretty cool your aproach to replying to my post though, shows you're a real nice guy and looking for concrete information.
Brad
Mar 11, 2004, 03:24 PM
#22
Here is a link to my Dyno run before and after.
https://www.evolutionm.net/forums/sh...threadid=38024
I have approximately 7000 miles with Ur pulley and seen no problems.
Before installing the Crank pulley I did a dyno run then the car was back off and installed the Crank pulley then right back on the dyno.
Hp 264.0 / QT 252.3 Before the crank pulley
Hp 279.0 / QT 264.6 After the crank pulley
I pick up 15 Hp and 12.3 QT after the pulley, with nothing else done to the car.
I don’t know what to think now. Everyone is down on the pulleys saying how bad they are. I saw where the pulley really made a difference in horsepower and torque.
https://www.evolutionm.net/forums/sh...threadid=38024
I have approximately 7000 miles with Ur pulley and seen no problems.
Before installing the Crank pulley I did a dyno run then the car was back off and installed the Crank pulley then right back on the dyno.
Hp 264.0 / QT 252.3 Before the crank pulley
Hp 279.0 / QT 264.6 After the crank pulley
I pick up 15 Hp and 12.3 QT after the pulley, with nothing else done to the car.
I don’t know what to think now. Everyone is down on the pulleys saying how bad they are. I saw where the pulley really made a difference in horsepower and torque.
Mar 12, 2004, 06:22 AM
#24
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When Al checked my evo which has a pulley, he found that there was not a knock reading problem. I have an XEDE and a dynoflash. This is why I mentioned the XEDE changing the knock sensor reading earlier in the tread.
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