Any one can tell me if this is true?
Question about under drive pulley
Moderators: daewoomofo, Moderators Group
Question about under drive pulley
I ask here because maybe some of you have one in other cars (mo daewoo) or some friends have it. I ask some friends here and one of them tell me that the UD pulley damage the engine with the past of the time.
Any one can tell me if this is true?
Any one can tell me if this is true?
I could be wrong but I doubt it. It's going to give the engine the ability to rev faster if it's a smaller diameter, and it will undoubtedly be lighter so reduce rotating mass. The only thing I can really forsee having trouble with is the fun pedal 
.
But like I said before, I could be wrong. These guys are pretty brilliant and may be able to give you a better answer.
.But like I said before, I could be wrong. These guys are pretty brilliant and may be able to give you a better answer.
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the pulley that you are replacing is called the harmonic balancer, it is used to absorve the dangerous harmonic frequencies the crank experiences. the vibrations in the crank at a certain rpm cank cause failure to occur to the crank if there is no damping system like the harmonic balancer. if you change the pulley, it's wize to include an harmonic balancer of some sort. if i were you, i'll read up on harmonic balancers and their use. before touching that system. look up harmonic balancer or torsional damper.
got drift?
here you go,debo890 wrote:the pulley that you are replacing is called the harmonic balancer, it is used to absorve the dangerous harmonic frequencies the crank experiences. the vibrations in the crank at a certain rpm cank cause failure to occur to the crank if there is no damping system like the harmonic balancer. if you change the pulley, it's wize to include an harmonic balancer of some sort. if i were you, i'll read up on harmonic balancers and their use. before touching that system. look up harmonic balancer or torsional damper.
Harmonic balancer
From Wikipedia, the free encyclopedia.
A harmonic balancer (also called crank pulley damper or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration.
Every time the cylinders fire, power is transmitted through the crankshaft. The front of the crankshaft takes the largest impact of this power. This causes it to move before the rear end of the crankshaft, resulting in a twisting motion. Then, when the power is removed from the front, the halfway twisted shaft unwinds and snaps back in the opposite direction. Although this unwinding process is quite small, it causes "torsional vibration."
To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The balancer is made of two pieces connected by a rubber disk, spring loaded friction discs, or both. When the power from the cylinder hits the front of the crankshaft, it tries to twist the heavy part of the damper, but ends up twisting the rubber or discs connecting the two parts of the damper. The front of the crank cannot speed up as much with the damper attached because the force is used to twist the rubber and speed up the damper wheel. This keeps the crankshaft operation calm and reduces vibration.
Retrieved from "http://en.wikipedia.org/wiki/Harmonic_balancer"
got drift?
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GsiTurbo
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While this may be correct, I do not entirely agree wiht this. All new generation engines come balanced from the factory, and some of them also use balancing shafts (like mitsubishi 2.0 and Sentra Spec-V or SE-R). Having said that, why then many companies (Unorthodox Racing, Ford Racing) sell replacement lightened UD pulley for vehicles that came from the factory with the damper? For example
- Ford Focus Zetec
- Nissan Sentra
- Honda
- Mitsubishi 2.0 Turbo
- Neon 2.0/2.4 turbo
Furthermore, one of the most popular ways to increase power in Mitsu/Nissan is to remove the BALANCE shafts...wait, this should make the engine explode!!! No, they run and make high power, and high revs.
On 2.0/2.2 engines, the timing belt and its tensioner will keep working to reduce the vibrations, if any. Also, the spring-loaded serpentine belt will do its job. Erfinder's Optra and my C20GET run with no problems (well, mine engine is blown due to detonation) using UD pulley, so do countless other vehicles worldwide.
Just like with any aftermarket performance parts, there is always a chance something may go wrong. This is why one will find a disclaimer on any aftermarket part stating they are not responsible for any direct or indirect damge to the vehicle.
Tom
- Ford Focus Zetec
- Nissan Sentra
- Honda
- Mitsubishi 2.0 Turbo
- Neon 2.0/2.4 turbo
Furthermore, one of the most popular ways to increase power in Mitsu/Nissan is to remove the BALANCE shafts...wait, this should make the engine explode!!! No, they run and make high power, and high revs.
On 2.0/2.2 engines, the timing belt and its tensioner will keep working to reduce the vibrations, if any. Also, the spring-loaded serpentine belt will do its job. Erfinder's Optra and my C20GET run with no problems (well, mine engine is blown due to detonation) using UD pulley, so do countless other vehicles worldwide.
Just like with any aftermarket performance parts, there is always a chance something may go wrong. This is why one will find a disclaimer on any aftermarket part stating they are not responsible for any direct or indirect damge to the vehicle.
Tom
__________________________
2002 Lanos 1.5 SOHC... stock!!!
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GsiTurbo
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- Joined: Thu Mar 13, 2003 10:56 pm
- Location: Edmonton, Alberta, Canada
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Here is more on UD pulley from the www.unorthodoxracing.com (FAQ section). This very well explaines the difference between the harmonic balancer, and the elastometer (rubber ring) incorporated into the factory crank pulley. This should answer all the questions...
Tom
http://www.unorthodoxracing.com/faq_pulleys.html
*************
4) "Is my crank pulley a harmonic/torsional/vibration damper or a harmonic balancer?"
People are getting their crank 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 engine problems 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.
Tom
http://www.unorthodoxracing.com/faq_pulleys.html
*************
4) "Is my crank pulley a harmonic/torsional/vibration damper or a harmonic balancer?"
People are getting their crank 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 engine problems 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.
__________________________
2002 Lanos 1.5 SOHC... stock!!!
The harmonic damper has nothing to do with the internal balancing of an engine...
The crank harmonics come from the firing pulses twisting the crank. The rpm at which the crank becomes resonant is influenced by the crank design and material, hp output and the masses attatched to either end of the crank.
For most modern 4 cylinder engine designs and outputs the crank becomes resonant at 8000-9000rpm. Failures tend to occur nearest the largest mass or force at the end of the crank ie the flywheel end or perhaps the accessory drive end if a supercharger is being used.
If the engine has a low maximum operating rpm a harmonic damper may not be required and many 4 cylinder engines do not use them. If however the maximum operating rpm is increased then a damper will be used. Bear in mind that prolonged operation at high rpm, whilst not operating in the cranks resonant frequency, the amplitude may still be large enough to damage the mains bearings and possibly cause ovalling of the mains.
High rpm 4 cylinder engines should use a damper if prolonged use at high rpm is to be encountered.
Bear in mind that modifications that are made to an engine, like adding a turbo to increase output, fitting a lighter flywheel etc. will shift the resonant peak of the crankshaft. Most OEM bonded rubber dampers (if fitted) will not be able to deal with a large shift. If the engine is highly modified the damper should be tuned to suit the new resonant peak. This means a new aftermarket damper.
I hope this helps a little...
Stef
The crank harmonics come from the firing pulses twisting the crank. The rpm at which the crank becomes resonant is influenced by the crank design and material, hp output and the masses attatched to either end of the crank.
For most modern 4 cylinder engine designs and outputs the crank becomes resonant at 8000-9000rpm. Failures tend to occur nearest the largest mass or force at the end of the crank ie the flywheel end or perhaps the accessory drive end if a supercharger is being used.
If the engine has a low maximum operating rpm a harmonic damper may not be required and many 4 cylinder engines do not use them. If however the maximum operating rpm is increased then a damper will be used. Bear in mind that prolonged operation at high rpm, whilst not operating in the cranks resonant frequency, the amplitude may still be large enough to damage the mains bearings and possibly cause ovalling of the mains.
High rpm 4 cylinder engines should use a damper if prolonged use at high rpm is to be encountered.
Bear in mind that modifications that are made to an engine, like adding a turbo to increase output, fitting a lighter flywheel etc. will shift the resonant peak of the crankshaft. Most OEM bonded rubber dampers (if fitted) will not be able to deal with a large shift. If the engine is highly modified the damper should be tuned to suit the new resonant peak. This means a new aftermarket damper.
I hope this helps a little...
Stef
Vauxhall Astra.
T3 60trim, Intercooler, Mopar Super 60 Injectors, SDS Stand Alone EFI, Cast T3 Manifold With External Wastegate + More...
T3 60trim, Intercooler, Mopar Super 60 Injectors, SDS Stand Alone EFI, Cast T3 Manifold With External Wastegate + More...
If I understand what everybody has written about the matter so far, you should have no problems. In any case it will help the engine rev faster, if you keep your regular shift point you shouldn't have a problem 
.
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intresting. ture if your engine is internally balanced you need not worry. but how balanced is the nubi's engine? i dont know. i am just very concerned. " to change the pulley is not a bad idea." just first find out how the engine is balanced.