δτεμι πεςγ μλξδ ριαεϊ:
1. μδεψιγ ξωχμ ξμα δξπες (δχψπχ).
2. μδΰθ ΰϊ ριαεαι ξωΰαϊ δξιν δΰμθψπθεψ δβδ λεη εωΰψ δβπαιν (εμδςμεϊ ΰϊ δδρτχ ωμ δξπες ϊεκ λγι...
3. ΰιο φεψκ αξΰζο ηιφεπι ιεϊψ.
μθεαϊ ξδ δτεμι δξεχθο?
δτεμι πεςγ μλξδ ριαεϊ:
1. μδεψιγ ξωχμ ξμα δξπες (δχψπχ).
2. μδΰθ ΰϊ ριαεαι ξωΰαϊ δξιν δΰμθψπθεψ δβδ λεη εωΰψ δβπαιν (εμδςμεϊ ΰϊ δδρτχ ωμ δξπες ϊεκ λγι...
3. ΰιο φεψκ αξΰζο ηιφεπι ιεϊψ.
ρθψεχψ- ξπες ξεβγμπλϊα αξχεψ ςμ ιγι LAREDO
δθςπδ ωμκ μβαι δξπεςιν δΰμε, αδχωψ ωμ δϊηξξεϊ, διϊδ ηγ ξωξςιϊ ωξπες ξεβγμ ιϊηξν ιεϊψ ξξπες ψβιμ.
ςν δτεμι ωιιφψϊ ετιψθϊ ΰϊ ξθψεϊιε, ΰϊδ ξεψιγ ριαεαι ξωΰαϊ ξιν.
δωΰμδ ωμι διΰ- ΰϊδ ξβγιμ ξςαψι ξιν λγι μτϊεψ ΰϊ δχθπϊ δτεμι εΰιϊε ΰϊ ϊτεχϊ ξωΰαϊ δξιν?
ξδ μβαι δβδ λη?
τηεϊ ριαεαιν, ιεϊψ χωιη. βν ΰϊ ζδ ΰϊδ τεϊψ αγψκ λμωδι ΰε ωζδ ειϊεψ ωφψικ μςωεϊ?
ρεσ ωαες ξΰεγ τψεγεχθιαι,
ωιξε μα μξωχμ δτεμι δηγω
μςεξϊ ξωχμ δτεμι διωο,
χφϊ ξδτψεχ
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ΰξιψ ΰδμο
λξδ δρτχ δτεμι ξερισ αιβμμ διεϊε χθο? εωΰμδ ωπιδ δΰν ΰιο αςιιϊ δϊηξξεϊ λϊεφΰδ ξλκ εαλξδ ΰηεζ δχθπθδ ΰϊ δτεμι (ΰϊδ μΰ ηιια μϊϊ ϊωεαδ ΰν ζδ ρεγι ΰπι ξϊςπιο αχωψ μζδ μξπες ωμ διμχρ)
θμ UNI
ηιγϊ διεν?.?
μΰ πηζιχ ΰϊλν αξϊη ξζψχ ΰηγ ωεπδ ξλμ δωΰψ,
θεα ιω μι ωπι ξλεπΰιν ξ"θεαι δξεξηιν" λαψ γιαψπε ςμ ξερλιν ωλεμμμμν ξξμιφιν εδψλα ωμι περς ςν 5 ξζψχιν ξρεβ ΰηγ εΰηγ ωεπδ, ζδ αθη "ΰαχϊ χρξιν" ωμ βε εαεμγεβ ξΰξψιχδ (δεξεψ ηαψιν)μωιτεψ δφψιλϊ γμχ
δπδ δξζψχιν δηγωιν
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μβαι δτεμι -
ΰλο δεΰ ξχθιο ΰϊ ρτιχϊ δξιν, ηωξμ ελε...
ξλιεεο ωδεΰ ξεχθο αιηρ χθο, ΰιο μγαψ λξςθ δωτςδ - λμ δξςψλεϊ δΰμε απειεϊ μςαεγ αξωκ ωςεϊ αρμ"γ ρψχ ωμ δξπες μμΰ δτψςδ.
μβαι ξςαψι ξιν - ΰλο δν ξεβγμιν αημχ ξδξχεξεϊ (ΰν διδ ιεϊψ ϊχφια διιϊι ξτψιγ ΰϊ δξςψλϊ μωϊι ξςψλεϊ αωϊι θξτ' ςαεγδ ωεπεϊ ςμ ξπϊ μιιςμ ςεγ ιεϊψ ΰϊ ςαεγϊ δξπες).
γαψ ηωεα ξΰεγ - αξπεςιν αδν δτεμι ξωξω λξωλκ ϊπεγεϊ ΰρεψ μωπεϊ ΰεϊε ΰν μΰ γεΰβιν μωιλεκ δϊπεγεϊ, δγαψ ηωεα αξιεηγ αξπεςι 4 φιμ'. δγαψ χωεψ μΰιζεο δξρδ δΰιπψθιϊ αργψ ωπι.
αξπες 6 φιμιπγψ ιω φεψκ μαφς ΰιζεο γιπξι μλμ δηαψδ αιηγ (χψπχ+θμθμιν+αελπεϊ+τεμι) ΰν ψεφιν μαπεϊ τεμι μμΰ ξωλκ.
ξδ δλ"ρ δξωεςψ ωιδιδ μξπες? αΰιζδ ρμ"γ?
δλϊαδ δπ"μ ξςπιιπϊ ξλξδ αηιπεϊ
γαψ ψΰωεο διΰ πιλϊαδ ς"ι ρθια γπΰο (Dinan) ωπηωα μξεξηδ ξρτψ 1 αΰψδ"α αωιτεψι ξπεςιν ωμ BMW.
γαψ ωπι διΰ ξραιψδ ΰϊ δηωιαεϊ ωμ δ Harmonic balancer μςαεγϊ δξπες.
The Danger of Power Pulleys & Understanding the Harmonic Damper
BY STEVE DINAN OF DINAN BMW
I have been threatening for a long time to write a series of technical articles to educate consumers and to dispel misconceptions that exist about automotive after-market technology. Motivated by problems with customer's cars resulting from the installation of power pulleys, I wish to explain the potential dangers of these products and address the damage they cause to engines.
The theory behind the power pulley is that a reduction in the speed of the accessory drive will minimize the parasitic losses that rob power from the engine. Parasitic power losses are a result of the energy that the engine uses to turn accessory components such as the alternator and water pump, instead of producing power for acceleration. In an attempt to minimize this energy loss, many companies claim to produce additional power by removing the harmonic damper and replacing it with a lightweight assembly. While a small power gain can be realized, there are a significant number of potential problems associated with this modification, some that are small and one which is particularly large and damaging!
The popular method for making power pulleys on E36 engines is by removing the harmonic damper and replacing it with a lightweight alloy assembly. This is a very dangerous product because this damper is essential to the longevity of an engine. The substitution of this part often results in severe engine damage.
It is also important to understand that while the engine in a BMW is designed by a team of qualified engineers, these power pulleys are created and installed by people who do not understand some very important principles of physics. I would first like to give a brief explanation of these principles which are critical to the proper operation of an engine.
1) Elastic Deformation
Though it is common belief that large steel parts such as crankshafts are rigid and inflexible, this is not true. When a force acts on a crank it bends, flexes and twists just as a rubber band would. While this movement is often very small, it can have a significant impact on how an engine functions.
2) Natural Frequency
All objects have a natural frequency that they resonate (vibrate) at when struck with a hammer. An everyday example of this is a tuning fork. The sound that a particular fork makes is directly related to the frequency that it is vibrating at. This is its "natural frequency," that is dictated by the size, shape and material of the instrument. Just like a tuning fork, a crankshaft has a natural frequency that it vibrates at when struck. An important aspect of this principle is that when an object is exposed to a heavily amplified order of its own natural frequency, it will begin to resonate with increasing vigor until it vibrates itself to pieces (fatigue failure).
3) Fatigue Failure
Fatigue failure is when a material, metal in this case, breaks from repeated twisting or bending. A paper clip makes a great example. Take a paper clip and flex it back and forth 90° or so. After about 10 oscillations the paper clip will break of fatigue failure.
The explanation of the destructive nature of power pulleys begins with the two basic balance and vibration modes in an internal combustion engine. It is of great importance that these modes are understood as being separate and distinct.
1) The vibration of the engine and its rigid components caused by the imbalance of the rotating and reciprocating parts. This is why we have counterweights on the crankshaft to offset the mass of the piston and rod as well as the reason for balancing the components in the engine.
2) The vibration of the engine components due to their individual elastic deformations. These deformations are a result of the periodic combustion impulses that create torsional forces on the crankshaft and camshaft. These torques excite the shafts into sequential orders of vibration, and lateral oscillation. Engine vibration of this sort is counteracted by the harmonic damper and is the primary subject of this paper.
Torsional Vibration (Natural Frequency)
Every time a cylinder fires, the force twists the crankshaft. When the cylinder stops firing the force ceases to act and the crankshaft starts to return to the untwisted position. However, the crankshaft will overshoot and begin to twist in the opposite direction, and then back again. Though this back-and-forth twisting motion decays over a number of repetitions due to internal friction, the frequency of vibration remains unique to the particular crankshaft.
This motion is complicated in the case of a crankshaft because the amplitude of the vibration varies along the shaft. The crankshaft will experience torsional vibrations of the greatest amplitude at the point furthest from the flywheel or load.
Harmonic (sine wave) Torque Curves
Each time a cylinder fires, force is translated through the piston and the connecting rod to the crankshaft pin. This force is then applied tangentially to, and causes the rotation of the crankshaft.
The sequence of forces that the crankshaft is subjected to is commonly organized into variable tangential torque curves that in turn can be resolved into either a constant mean torque curve or an infinite number of sine wave torque curves. These curves, known as harmonics, follow orders that depend on the number of complete vibrations (cylinder pulses) per revolution.
Accordingly, the tangential crankshaft torque is comprised of many harmonics of varying amplitudes and frequencies. This is where the name "harmonic damper" originates.
Critical RPM's
When the crankshaft is revolving at an RPM such that the torque frequency, or one of the harmonic sine wave frequencies coincides with the natural frequency of the shaft, resonance occurs. Thus, the crankshaft RPM at which this resonance occurs is known a critical speed. A modern automobile engine will commonly pass through multiple critical speeds over the range of its possible RPM's. These speeds are categorized into either major or minor critical RPM's.
Major and Minor Critical RPMs
Major and minor critical RPM's are different due to the fact that some harmonics assist one another in producing large vibrations, whereas other harmonics cancel each other out. Hence, the important critical RPMs have harmonics that build on one another to amplify the torsional motion of the crankshaft. These critical RPMs are know as the "major criticals". Conversely, the "minor criticals" exist at RPM's that tend to cancel and damp the oscillations of the crankshaft.
If the RPM remains at or near one of the major criticals for any length of time, fatigue failure of the crankshaft is probable. Major critical RPMs are dangerous, and either must be avoided or properly damped. Additionally, smaller but still serious problems can result from an undamped crankshaft. The oscillation of the crankshaft at a major critical speed will commonly sheer the front crank pulley and the flywheel from the crankshaft. I have witnessed front pulley hub keys being sheered, flywheels coming loose, and clutch covers coming apart. These failures have often required crankshaft and/or gearbox replacement.
Harmonic Dampers
Crankshaft failure can be prevented by mounting some form of vibration damper at the front end of the crankshaft that is capable of absorbing and dissipating the majority of the vibratory energy. Once absorbed by the damper the energy is released in the form of heat, making adequate cooling a necessity. This heat dissipation was visibly essential in Tom Milner's PTG racing M3 which channeled air from the brake ducts to the harmonic damper, in order to keep the damper at optimal operating temperatures. While there are various types of torsional vibration dampers, BMW engines are primarily designed with "tuned rubber" dampers.
It is also important to note that while the large springs of a dual mass flywheel absorb some of the torsional impulses conveyed to the crankshaft, they are not harmonic dampers, and are only responsible for a small reduction in vibration.
In addition to the crankshaft issue, other problems can result from slowing down the accessories below their designed speeds, particularly at idle. Slowing the alternator down can result in reduced charging of the battery, dimming of the lights, and computer malfunctions. Slowing of the water pump and fan can result in warm running, while slowing of the power steering can cause stiff steering at idle and groaning noises. It is possible to implement design corrections and avoid these scenarios, but this would require additional components and/or software.
εΰν δξωτθ δζδ πψΰδ μλν ξελψ ξΰιτεωδε
The theory behind the power pulley is that a reduction in the speed of the accessory drive will minimize the parasitic losses that rob power from the engine. Parasitic power losses are a result of the energy that the engine uses to turn accessory components such as the alternator and water pump,
πλϊα αξχεψ ςμ ιγι LAREDO
ξζψχιν #24 ?? ζδ μΰ ιεϊψ ξγι? (ζδ αργψ μξπες ωμ 280 λ"ρ... ΰϊν ξλεεπιν μων? )
ΰρσ.
"scars are tattoos with better stories"
ΰιο ϊλπιϊ. ηιιν. πχεγδ.
δχξτψ - VW TYPE 2 1978 | δθπγψ - διιμχρ 2008
ΰϊδ ξϊλεεο ωζδ αργψ μξπες ωαπει μϊϊ ΰϊ δϊετχδ ωμε α2800-3000 ρμ"γ εξςμδ...πλϊα αξχεψ ςμ ιγι asafk
δλμ τεψχ,
πωθσ, πεχδ , ξηψ ιιφας λξε ωφψικ εϊϊηιμ ϊδμικ δδψλαδ
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ηρψ μι ΰιζδ ΰεν ξωεν ξδ
ξηψ δλμ ιτεψχ μψξϊ δαεψβ ,ιπεχδ ιωετωσ,ιωειισ,ιεημσ,ιιφας ,ιβεψζ,επϊηιμ ατΰζμ
ρελπεϊ δαθεη δβγεμδ εδεεϊιχδ αΰψυ μϊψαεϊ δτπΰι
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ψΰωιϊ ΰχγιν εΰεξψ μιιγιςϊ λεμν ,
ΰπι τςν ΰηψεπδ ξζξιο ξρξιθψιιριπβ, ΰεμι διεν ιεφΰ δξωμεη ωμι,
ψχ ριτεψι ραϊΰ,
ΰδδδδ δημχ ξβις α 23 μιπεΰψ ,.??
ΰξψϊν ιω αξμΰι ,μΰ ΰιο ζδ αξηρο δωπι ωμπε, ???
ξωΰαϊ ξιιν ΰιο ιδιδ ςεγ ωαες ,ψΰαχ ξφειιο ωιω μλν αξμΰι ,
δλψθιρ ΰωψΰι μΰ ςαψ??...
ξδ?..? ηιιαϊν ΰεϊι ειω μι ξιιμ ξλν ωξΰωψ ωΰϊ εςλωιε ωςαψε ωαεςιιν ΰϊν θεςπιν ζΰϊ???
ελο δμΰδ ελο δμΰδ, μΰ ΰϊτμΰ ΰν ιηιιαε ΰεϊι τςξιιν,
ωψεϊ ιν ϊιλεπι ξφειι, ΰηϊ δηαψεϊ δλι ΰξιπεϊ ωιω, δλι ψφιπιεϊ ωιω ,λμ δτψειιχθ ϊχες ωαεςιιν ιξιν,
ςεγ ξςθ ΰφμφμ μαγεχ ΰν αλμμ ιφΰ δξωμεη .
λτι ωΰξψϊι αψΰωιϊ δλϊαδ , ΰπι μΰ ξτηγ μψωεν ΰϊ δωθειεϊ ωμι ,εΰν ξιωδεΰ ιηρεκ ξλκ ηφι ωχμ ΰε ιιξπς λΰαι μα ξςφξε δψεεηϊι,
διεν: πρςϊι μωτν ,χψφτπε,ωιιτπε,βιψγπε,εφαςπε,
ϊιχεο ψιϊεκ ωμ ηιζεχ δρψο ,λδβγψϊ "ωτν" χχδ ωμ φιτεψιν-φεγχ:twisted: :twisted: :twisted:
ΰφμ δωτν ΰιο φαιςδ ςμ δημεγδ, ιω ργψ ,ψΰωιϊ ωεθτιν,ωπιϊ ξχψφτιν,ΰηψι ζδ λτι ωδωτν ΰεξψ "ΰηεψι ζδ" ξξιψ ημεγδ εΰζζζζζ
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πλϊα αξχεψ ςμ ιγι lizard
ξδ αΰξϊ δεμκ μδιεϊ δδρτχ δξωεςψ ωμ δξπες δζδ?πλϊα αξχεψ ςμ ιγι six 4 life
αΰιζδ ρμ"γ ξϊελπο ωιΰ ξεξπθ, αΰιζδ ρμ"γ ξϊελπο ωιΰ δρτχ (λ"ρ)?
ξδ δδςψλδ ωμ δωιΰιν δΰμδ?
ςεξψ
ηεψπι, ηεψπι, ΰαμ ιεγς ςμ ΰιζδ φγ ωμ δξαψβ γετχιν ςν δτθιω.
διεν ωμι λαψ ςαψ.
Don't make me break my foot in your ass
δπϊεπιν ξδι δξθψδ μδβις ΰμιδ εδϊεφΰεϊ δρετιεϊ
ιτεψρξε μΰηψ βξψ δωιτευ λεμμ αγιχδ ξξεηωαϊ ωπςψλδ ααεω μτπι δωιτευ εϊςψκ μΰηψιε,
εμΰ γχδ ΰηϊ μτπι λο,
λμ δπϊεπιν ,ϊδμικ αιφες δςαεγδ,ξδ ιωεπδ,ιωετυ,ιωετφψ,ιεημσ, δλμ πιϊο λϊεα μτπι ϊηιμϊ δωιτευ,
ειΰεξϊ μΰηψιε ξεμ δϊεφΰεϊ.
ξψ αεμγεβ διχψ, ϊεαπεϊ εδςψεϊ ςπιιπιεϊ εμχηιν ξτψειιχθ δωιτευ ωμκ ιϊχαμε ςμ ιγι δηϊεν ξθδ αψφεο εαΰδαδ
ξΰιψ
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δμεπλϊα αξχεψ ςμ ιγι ξΰιψ ψεθαψβ
ξΰιψχ'δ
ξδ ωΰϊδ ΰεξψ μξςωδ
ζδ ωΰϊν μΰ ξϊλεεπιν μϊϊ πϊεπιν, μτπι ωδξπες απει ςεαγ επξγγ?
ξδ ςωιπε αλμ ζδ?
δψςιεο δεΰ ωϊβιγε ξδ δξθψδ, ςεγ αλμμ μτπι ϊηιμϊ δςαεγδ ςμ δξπες, ςν τιψεθ λξε ωφψικ.
μΰηψ ριεν δςαεγδ- λεμπε πελμ μψΰεϊ λξδ χψεα δβςϊν ΰμ δξθψδ, ΰηψι δξγιγεϊ δψμεεπθιεϊ.
ΰι δφδψϊ δξθψεϊ αΰωψ μδρτχιν, αθεεηι ρμ"γ ελε', ξϊτψω (μτηεϊ ξαηιπϊι) αφεψδ ω- ΰιο λΰο ϊελπιϊ ςαεγδ ξτεψθϊ ςν ξθψδ αρετδ, ΰμΰ μαπεϊ ρθψεχψ μδερισ με ΰι ΰιμε ϊερτεϊ εαρετε ωμ γαψ μξγεγ εμψΰεϊ λξδ ιφΰ.
ξδ ωιχψδ ατεςμ
αεΰ ππιη δφμηϊν μρηεθ 250 λ"ρ ξδξπες
ξδ ξεπς ξξλν μδφδιψ ΰεχιι, ΰπηπε λιεεπε μθεεη ωμ 220-250 λ"ρ, εδβςπε μων.
αχιφεψ
ϊο τιψεθ δρτχιν λαψ ςλωιε, μτπι δξγιγεϊ μΰηψ ωδξπες απει εςεαγ, ΰν ΰϊδ ψεφδ μςωεϊ ΰϊ ζδ λξε ωφψικ.
ΰν ζε μΰ δλεεπδ, δξγιγεϊ δΰμε μΰ ωεεϊ λμεν μχεψΰιν ωψεφιν μψΰεϊ μΰιζδ ψξϊ γιεχ εαπιδ αςμ δξχφες ωμκ ξβις.
μςπιεϊ γςϊι δΰπωιν διηιγιν ωαΰξϊ φψικ μδιεϊ μδν ηωεα ξδ ΰηεζ δγιεχ απϊεπι δξπες δρετιιν δν ξΰιψ εΰξιψ .
δμΰ μΰ ξγεαψ λΰο αδϊςψαεϊ / ξαηο / ΰιζεωδιΰ δϊηιιαεϊ λμτι δτεψεν.
ξφγ ωπι
ξΰιψ, ΰν μΰ ϊτψθ ξδ λεεπεϊικ αξχεν θιτιν εδς/ΰψεϊ μϊλπιϊ ϊελμ μχαμ ψχ γιεο αγιςαγ ΰν ξδ ωςωιϊ διδ θεα ΰε μΰ ελξδ .
ηαμ μτρτρ ΰϊ δψςιεπεϊ εδδφςεϊ μωιτεψ ωϊελμ μχαμ ξδηαψ'δ ατεψεν.
ωμεξι
αγψκ
ωμεξιπλϊα αξχεψ ςμ ιγι ωμεξι
ΰιο λΰο δϊςψαεϊ ΰε ξαηο λμωδε
ξγεαψ λΰο ςμ ξπες ρθψεχψ- ξπες ξεβγμ
δλϊαδ πςωιϊ ςφν ζΰϊ ωδεΰ ξπες ξεβγμ, επαπδ μδρτχιν ξρειιξιν, εζδ μΰ ςεγ ξπες ρθπγψθι ωπλπρ μωιτευ.
πεωΰ δρθψεχψ ξςπιιο ψαιν ξδηαψιν ωψλεαιν ςμ ρετεϊ εCJΰιν - μψεα αβμμ δδρτχιν ωπθςπιν ωδν ξεφιΰιν, ειω ςμιδν δψαδ γιςεϊ.
λΰο αεπδ ΰϊ δξπες ΰξιψ ωθςο μΰ τςν εμΰ τςξιιν ωπιϊο μδεφιΰ ξξπες δρετδ 250-270 λεηεϊ ρερ μμΰ ηψιθδ μΰεαψριιζ
εζε δδζγξπεϊ μψΰεϊ ΰν ΰλο ιω βα μγαψιν, εΰτιμε μμξεγ ξδτψθιν δξςθιν ωπιϊπιν λΰο.
ΰν ζδ διδ ρϊν ςεγ ΰεαψεμ, ρτχ ΰν διδ φεψκ αλϊαδ περτϊ (ιω λαψ 2)
ψεα εςιχψ δςπιιο αλμ δςαεγδ δρτφιτιϊ δζε διΰ δδρτχ δρετι
εμμΰ δτιψεθ ςμ ζδ... ΰπι ηεωα ωδξθψδ τερτρδ.
ΰαμ ζε γςϊι
ιλεμ μδιεϊ ωμΰ δαπϊι πλεο, εζδ αβγεμ ςεγ ΰεαψεμ... εξδ ωιφΰ ιφΰ.
εΰψζ, ζδ μΰ ρϊν ςεγ ΰεαψεμ, μΰ διδ λζδ ΰεαψεμ ωαιΰ μλμ λκ δψαδ γιεπιν θλπιιν αΰϊψ.
μτηεϊ γαψ ΰηγ λαψ δψεεηπε ξζδ.[/QUOTE]
ψεΰιν ηαψιν , ιω ΰτιμε δρλξδ αιπι εαιο δαεμγεβ, λεμν λαψ δψεειηε ξλκ,
ΰωχεμ ΰϊ αχωϊλν εΰϊτπδ μλκ αξδμκ δςψα
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