High performance pully question
Registered User
Joined: Feb 2003
Posts: 858
Likes: 1
From: Sunny San Diego
Re: High performance pully question
Yes it does make about a 5RWHP difference but there are risks involved. Unorthodox Underdrive Crank pully does not have harmonic dampeners, so this could seriously affect the rod bearings. I have seen nightmare stories about it on other forums from 300ZXs to Mustangs...
The final question is it worth the risk...
- Don't argue with idiots. They will bring you down to their level and beat you with experience.=P-
The final question is it worth the risk...
- Don't argue with idiots. They will bring you down to their level and beat you with experience.=P-
Registered User
Joined: Apr 2003
Posts: 221
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From: The Woodlands, TX
Re: High performance pully question
The guy at my performance shop who can take apart and rebuild Nissan engines with his eyes closed said this is a load of crap and there's no danger what-so-ever. The stock crank pulley does not have harmonic dampers.
Here's what UR has to say about it:
People are getting the pulleys confused with the harmonic dampers found on some V6 / V8 engines. "Harmonic Balancer" is a term that is used loosely in the automotive industry. Technically, this type of device does not exist. The "balancer" part comes from engines that are externally balanced and have a counterweight cast into the damper, hence the merging of the two terms. None of the applications that we offer utilize a counterweight as part of the pulley as these engines are internally balanced.
The pulleys on most of the new import and smaller domestic engines have an elastomer (rubber ring) incorporated into the pulley that looks similar to a harmonic damper. The elastomer in the OEM pulley serves as an isolator, which is there to suppress natural vibration and noise from the engine itself, the A/C compressor, P/S pump, and alternator. This is what the manufacturers call NVH (Noise Vibration & Harshness) when referring to noticeable noise and vibration in the passenger compartment. It is important to note that in these applications, this elastomer is somewhat inadequate in size, as well as life span, to act as an effective torsional damper. If you look at the pulleys on some of the imports there is no rubber to be found at all. We have samples of these, mostly from Acura/Honda, the Nissan Altima, 1.8L Eclipse, 2.3L Fords, Chrysler 2.2L's, and 1.8L VW's, to mention a few. This is not to say that with our pulleys you will hear a ton of noise or feel more vibration from your engine compartment. Most who have installed and driven a vehicle with our pulleys will notice the engine actually feels smoother. This is a natural result of replacing the heavy steel crank pulley with a CNC-machined aluminum pulley. NVH is variable and unique to every car. NVH will increase with the installation of an aftermarket intake and/or exhaust, for example. Think of OEM intake systems in newer cars, they use baffles and resonators in the intake to quiet all the intake noise. Aftermarket intakes eliminate these resonators and create dramatic increases in engine noise from the throttle opening and closing. So to most tuners, certain types of NVH can make the driving experience more enjoyable.
The purpose of a traditional harmonic damper is to protect against crank failure from torsional movement. This is not necessary in most modern engines because of the many advances in engine design and materials. Factors such as stroke, displacement, inline, V configurations, power output, etc., do determine when and how these harmonics and torsional movements occur.
Again, there is a lot of internet hearsay about the pulleys. When motor failures occur, too often people are quick to blame the pulley first, rather than taking the time to look logically into why there was a problem. We hope that after reading this you will understand the crank pulleys better.
'03 AT Sedan | Brilliant Silver | Willow Leather | Sport | Premium | Aerokit w/Spoiler | Nav
Here's what UR has to say about it:
People are getting the pulleys confused with the harmonic dampers found on some V6 / V8 engines. "Harmonic Balancer" is a term that is used loosely in the automotive industry. Technically, this type of device does not exist. The "balancer" part comes from engines that are externally balanced and have a counterweight cast into the damper, hence the merging of the two terms. None of the applications that we offer utilize a counterweight as part of the pulley as these engines are internally balanced.
The pulleys on most of the new import and smaller domestic engines have an elastomer (rubber ring) incorporated into the pulley that looks similar to a harmonic damper. The elastomer in the OEM pulley serves as an isolator, which is there to suppress natural vibration and noise from the engine itself, the A/C compressor, P/S pump, and alternator. This is what the manufacturers call NVH (Noise Vibration & Harshness) when referring to noticeable noise and vibration in the passenger compartment. It is important to note that in these applications, this elastomer is somewhat inadequate in size, as well as life span, to act as an effective torsional damper. If you look at the pulleys on some of the imports there is no rubber to be found at all. We have samples of these, mostly from Acura/Honda, the Nissan Altima, 1.8L Eclipse, 2.3L Fords, Chrysler 2.2L's, and 1.8L VW's, to mention a few. This is not to say that with our pulleys you will hear a ton of noise or feel more vibration from your engine compartment. Most who have installed and driven a vehicle with our pulleys will notice the engine actually feels smoother. This is a natural result of replacing the heavy steel crank pulley with a CNC-machined aluminum pulley. NVH is variable and unique to every car. NVH will increase with the installation of an aftermarket intake and/or exhaust, for example. Think of OEM intake systems in newer cars, they use baffles and resonators in the intake to quiet all the intake noise. Aftermarket intakes eliminate these resonators and create dramatic increases in engine noise from the throttle opening and closing. So to most tuners, certain types of NVH can make the driving experience more enjoyable.
The purpose of a traditional harmonic damper is to protect against crank failure from torsional movement. This is not necessary in most modern engines because of the many advances in engine design and materials. Factors such as stroke, displacement, inline, V configurations, power output, etc., do determine when and how these harmonics and torsional movements occur.
Again, there is a lot of internet hearsay about the pulleys. When motor failures occur, too often people are quick to blame the pulley first, rather than taking the time to look logically into why there was a problem. We hope that after reading this you will understand the crank pulleys better.
'03 AT Sedan | Brilliant Silver | Willow Leather | Sport | Premium | Aerokit w/Spoiler | Nav
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Registered User
Joined: Oct 2003
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Re: High performance pully question
WOW!!! that sure answered my question thanks a million...So in essence what are we looking at if these pullies are installed in regards to performance enhancements???
Joined: Jun 2002
Posts: 30,341
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From: Cambridge, Ont. Canada
Re: High performance pully question
Negligable increase in hp (only about 5) but it saves on the accessories by lowering their speed. Depending on circumstances, it may decrease alternator output to below what is needed, so that must be monitored. Likewise the water pump is slowed and may not be as effective as needed.
These circumstances are an extreme, and probably won't affect you at all.
GSM
<font color=red>GSM</font color=red> <font color=black>Silverstone Coupe</font color=black>
These circumstances are an extreme, and probably won't affect you at all.
GSM
<font color=red>GSM</font color=red> <font color=black>Silverstone Coupe</font color=black>
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