difference in pulley's?
12-20-2005, 04:56 AM
#1
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difference in pulley's?
ok the on going discussion about pulleys whether they are good or bad.. blah blah
jus shut it and keep it to yoruself.
i jus want my question answered with out going on to different topics.!
what is the physicall difference between our stock crank pulley and an aftermarket crank pulley such as ZPI's? installed and not installed?
jus shut it and keep it to yoruself.
i jus want my question answered with out going on to different topics.!
what is the physicall difference between our stock crank pulley and an aftermarket crank pulley such as ZPI's? installed and not installed?
12-20-2005, 05:14 AM
#2
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Weight.
The NST pulley is also size - Which gives more HP as well.
There is also a physical difference with a rubber "Dampener" which was designed to absorb vibration, thus the debate regarding harmonic vibrations and damage. The A/M pulley options don't include that rubber in their design.
The lighter weight allows them to spool quicker, resulting in an HP increase... the underdrive gives less HP to the accesories, freeing up power as well.
That's pretty much the sum of how they work and what the physical difference is.
The NST pulley is also size - Which gives more HP as well.
There is also a physical difference with a rubber "Dampener" which was designed to absorb vibration, thus the debate regarding harmonic vibrations and damage. The A/M pulley options don't include that rubber in their design.
The lighter weight allows them to spool quicker, resulting in an HP increase... the underdrive gives less HP to the accesories, freeing up power as well.
That's pretty much the sum of how they work and what the physical difference is.
12-20-2005, 10:48 PM
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Ok, some information for you regarding pulleys and differences:
OEM pulleys are built using steel or cast iron. They also include what is called a dampner, which is a rubber band sandwiched in the pulley. This is supposed to lower potential vibrations, blah blah blah. Sometimes due to old age these rubber pieces actually crack and cause the pulley to break off!!! Before you flame me, I have actually seen this happen several times in person at autocross and drift events! It may or may not happen, just part of life.
Aftermarket pulleys are built using aluminum, good pulleys are built using aircraft quality material and are thus much much lighter than steel or iron pulleys. Some are OEM sized (lightweight), some are underdrive (to slow down) for n/a and turbo cars, some are overdrive (to speed up) for supercharged cars. Most aftermarket pulleys do not include the rubber dampner because incorporating such a design would cost A LOT more than building solid pieces. Basically customers do not want to pay $300 for an aftermarket crank pulley.
Finally, the benefits with the use of aftermarket pulleys are as follows:
1. Weight reduction. Aftermarket pulleys that are lighter than OEM pulleys will result in better throttle responce and improved times. An example of this is the ZPI, www.zpiracing.net, or the Unorthodox pulley. Same size as stock, less weight.
2. Underdriving. Slowing down accessories sends less HP to these accessories and more to the wheels instead. Underdrive pulleys will show better results than ones that are OEM sized. They provide better throttle responce, improved times, and extra HP on a dyno. An example of this type of pulley is the NST one, www.NonStopTuning.com. Smaller than stock, less weight.
I think that about covers it, hopefully you got the info you were seeking. Just as a reference, I got all of this info over the past few months from talking to an NST repp on AIM, I have been using their pulleys for several years and I would never go back to stock stuff!
OEM pulleys are built using steel or cast iron. They also include what is called a dampner, which is a rubber band sandwiched in the pulley. This is supposed to lower potential vibrations, blah blah blah. Sometimes due to old age these rubber pieces actually crack and cause the pulley to break off!!! Before you flame me, I have actually seen this happen several times in person at autocross and drift events! It may or may not happen, just part of life.
Aftermarket pulleys are built using aluminum, good pulleys are built using aircraft quality material and are thus much much lighter than steel or iron pulleys. Some are OEM sized (lightweight), some are underdrive (to slow down) for n/a and turbo cars, some are overdrive (to speed up) for supercharged cars. Most aftermarket pulleys do not include the rubber dampner because incorporating such a design would cost A LOT more than building solid pieces. Basically customers do not want to pay $300 for an aftermarket crank pulley.
Finally, the benefits with the use of aftermarket pulleys are as follows:
1. Weight reduction. Aftermarket pulleys that are lighter than OEM pulleys will result in better throttle responce and improved times. An example of this is the ZPI, www.zpiracing.net, or the Unorthodox pulley. Same size as stock, less weight.
2. Underdriving. Slowing down accessories sends less HP to these accessories and more to the wheels instead. Underdrive pulleys will show better results than ones that are OEM sized. They provide better throttle responce, improved times, and extra HP on a dyno. An example of this type of pulley is the NST one, www.NonStopTuning.com. Smaller than stock, less weight.
I think that about covers it, hopefully you got the info you were seeking. Just as a reference, I got all of this info over the past few months from talking to an NST repp on AIM, I have been using their pulleys for several years and I would never go back to stock stuff!
12-21-2005, 06:40 AM
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rubber band sandwiched in the pulley...
and i believe you said the aftermarket one doesnt have this rubber piece called a "dampener?"
is there any way i can take this rubber piece from teh stock and put it on the aftermarket?
are there picture comparions?
i ask all of this because i want the benefits of the a pulley but want to be very cautious with the experience of many others who had negative effects.
and i believe you said the aftermarket one doesnt have this rubber piece called a "dampener?"
is there any way i can take this rubber piece from teh stock and put it on the aftermarket?
are there picture comparions?
i ask all of this because i want the benefits of the a pulley but want to be very cautious with the experience of many others who had negative effects.
12-21-2005, 01:57 PM
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If you go with OEM-sized, and its installed properly, you should have ZERO problems down the line.
If you go with underdriven... On most cars with underdriven pulleys, there is talk of adding more stress to the electrical components as they are getting less power than for which they were designed. Particularly, the alternator.
However, this matters on a wide number of factors, including the design of the alternator, how much "underdriven" the pulleys are, your electrical demands (stereo, etc.), etc. etc.
In some cars, like my old Jetta, pulleys were a bad idea. On the tC, I haven't seen too many problems with the NST pulley, and I think this might be the way to go.
If you go with underdriven... On most cars with underdriven pulleys, there is talk of adding more stress to the electrical components as they are getting less power than for which they were designed. Particularly, the alternator.
However, this matters on a wide number of factors, including the design of the alternator, how much "underdriven" the pulleys are, your electrical demands (stereo, etc.), etc. etc.
In some cars, like my old Jetta, pulleys were a bad idea. On the tC, I haven't seen too many problems with the NST pulley, and I think this might be the way to go.
12-21-2005, 03:27 PM
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Buy the whole package.... underdrive for the crank and overdrive for the water and alternator... That will free up some HP and not comprimise your electrical system...
You don't have to really worry about your electrical unless you're running some major audio anyways....
You don't have to really worry about your electrical unless you're running some major audio anyways....
12-21-2005, 10:58 PM
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Ok, looks like WeDriveScions pretty much answered these questions, but here are some answers for you guys:
"is there any way i can take this rubber piece from teh stock and put it on the aftermarket? " No, there is not. These things have to be built into the pulley when in production. I asked NST why they do not design their pulleys with the rubber and they basically said drivers would not be willing to pay $300 or more for a crank pulley of this type. Frankly I agree. Also with old age they have seen the rubber fall out and actually break the pulley off the car!!! Many people actually like using solid pulleys. It should be added that although there are some people who swear up and down that removing the rubber is a bad idea, none of them have ever actually used pulleys to verify engine failure as a result of a pulley! On the other hand people who have been using these pulleys around here for quite some time have never had personal problems with pulleys either!
"what do they all do exactly? Is it smart to buy all four?"
NST offers 3 pulleys for the n/a or turbo tC. Crank, Alternator, Waterpump. The crank pulley makes all the power we want while underdriving accessories. The alternator pulley brings the alternator charge back up so we do not have to worry about the potential of efficiency loss. The waterpump pulley finishes off the package. If you can afford it pick up the full set, if not just pick up the crank and you will still be fine. The only time alternators suffer with underdrive crank pulleys is when they are trying to power MASSIVE audio systems.
Have fun guys
"is there any way i can take this rubber piece from teh stock and put it on the aftermarket? " No, there is not. These things have to be built into the pulley when in production. I asked NST why they do not design their pulleys with the rubber and they basically said drivers would not be willing to pay $300 or more for a crank pulley of this type. Frankly I agree. Also with old age they have seen the rubber fall out and actually break the pulley off the car!!! Many people actually like using solid pulleys. It should be added that although there are some people who swear up and down that removing the rubber is a bad idea, none of them have ever actually used pulleys to verify engine failure as a result of a pulley! On the other hand people who have been using these pulleys around here for quite some time have never had personal problems with pulleys either!
"what do they all do exactly? Is it smart to buy all four?"
NST offers 3 pulleys for the n/a or turbo tC. Crank, Alternator, Waterpump. The crank pulley makes all the power we want while underdriving accessories. The alternator pulley brings the alternator charge back up so we do not have to worry about the potential of efficiency loss. The waterpump pulley finishes off the package. If you can afford it pick up the full set, if not just pick up the crank and you will still be fine. The only time alternators suffer with underdrive crank pulleys is when they are trying to power MASSIVE audio systems.
Have fun guys
12-23-2005, 11:53 PM
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Originally Posted by Stu_Gotti
I just bought all 3 of them from NST.. Screw it! I need mo powa 
Screw it! I need mo powa And as far as installation goes, you can DIY if you have power tools and have turned a wrench or two on your car before. If you have not, then go to a good mechanic and have a professional do it for you. It should cost about 75 bucks or so for the 3 piece installation.