why is lightened crank pulley bad but not lightened flywheel?
12-12-2006, 04:24 PM
#1
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why is lightened crank pulley bad but not lightened flywheel?
So I know I'll get flammed lol, but im wondering. I just put on a lightened flywheel and was thinkin that it seems like that would have the same affect on the harmonic balance as a lightened crank pulley would on the other end of the crank. Is it cause the mainshaft from the tranny goin into the crank causes the flywheel not to affect harmonic balance?
12-12-2006, 04:26 PM
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I see where you're coming from but the reason the lightened crank pulleys are rumored to be bad is due to their lack of a harmonic balancer like the stock pulley.
12-12-2006, 07:59 PM
#5
Re: (4bidden)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4bidden »</TD></TR><TR><TD CLASS="quote">I see where you're coming from but the reason the lightened crank pulleys are rumored to be bad is due to their lack of a harmonic absorber like the stock pulley.</TD></TR></TABLE>
fixed for ya
There is a large difference between a dampener and an absorber.....A dampener takes energy in and converts it to a different form of energy to get rid of it, i.e the fluidampr, which takes vibrations on the crank and converts them to heat energy to be dissipated in the fluid inside....
An absorber takes vibrations in and outputs opposing vibrations to counter them, the stock pulley does this with the little rubber ring between the main pulley and the accessory pulley section.
Balanced or not the "lightweight" aftermarket pullies do nothing to address harmonic vibrations in the crank.....
fixed for ya
There is a large difference between a dampener and an absorber.....A dampener takes energy in and converts it to a different form of energy to get rid of it, i.e the fluidampr, which takes vibrations on the crank and converts them to heat energy to be dissipated in the fluid inside....
An absorber takes vibrations in and outputs opposing vibrations to counter them, the stock pulley does this with the little rubber ring between the main pulley and the accessory pulley section.
Balanced or not the "lightweight" aftermarket pullies do nothing to address harmonic vibrations in the crank.....
12-13-2006, 05:54 PM
#6
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Re: (bb4ever)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever »</TD></TR><TR><TD CLASS="quote">An absorber takes vibrations in and outputs opposing vibrations to counter them, the stock pulley does this with the little rubber ring between the main pulley and the accessory pulley section.</TD></TR></TABLE>
How does the stock pulley "output opposing vibrations"?
How does the stock pulley "output opposing vibrations"?
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12-13-2006, 06:28 PM
#9
Torsional absorbers, in design, can be "tuned" to a certain rpm range in which to function the greatest, which I can only assume honda tuned to the rpm range in which the h22 crank has the worst vibration...
The fluidampr is fairly effective over the whole rpm range, but if the absorber is tuned properly, it will be more effective in its specific range, but out of its range, the fluidampr is better
The fluidampr is fairly effective over the whole rpm range, but if the absorber is tuned properly, it will be more effective in its specific range, but out of its range, the fluidampr is better
12-13-2006, 07:48 PM
#10
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Re: (bb4ever)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever »</TD></TR><TR><TD CLASS="quote">My wording was a bit off....absorbers store and release energy to counteract vibrations....</TD></TR></TABLE>
Can you point me to a source the discusses the differences between an absorber and a damper? I've never made a distinction between the two. I'm no engineering major, though.
Can you point me to a source the discusses the differences between an absorber and a damper? I've never made a distinction between the two. I'm no engineering major, though.
12-14-2006, 06:56 AM
#11
http://www.kitcarmag.com/techa..._tech/
from ^^ article, there is a good basic explanation:
"Our English friends call a shock absorber a dampener, which may be a better name, because its job is to dampen the oscillation of the spring. The spring controls and absorbs road shock and vehicle weight transfer, not the shocks."
So, the dampener, "shock", dampens the movement of the spring up and down by taking the kinetic energy as it moves and forces air or oil through a small hole inside, converting kinetic energy to potential energy (when the shock is in the compressed state) and heat energy (the air/oil heats up when forced through the valve)
The spring, however, absorbs the "bumps" that the car receives from the road. It takes in energy as the suspension compresses and outputs opposing energy (spring force against compression) in order to return to equilibrium.
The crank can be looked at in the same light. The snout of the crank vibrates in any of the 360 degrees around it, so the rubber ring on the crank pulley is like a spring in the suspension. Is it obvious now that it doesn't matter where this rubber ring is located? Think about it in suspension terms, it doesn't matter what unsprung weight there is in between the spring and the road, the spring is still going to do its job. As long as it has metal attached to the inner and outer sides of it, it is going to absorb vibrations, so not that this would be a reality, but a concentric rubber ring on the flywheel would do the same thing.
The main difference is in how the energy is output once received. Both absorbers and dampeners receive energy in the same manner. An absorber takes that energy and outputs it in the same form. A dampener in effect takes the received form of energy out of the system, by converting it to another type of energy. The fluidamper takes in vibrations, coverts them to heat, and then dissipates the heat into the ambient air in the engine bay.
I'll look for a wikipedia article or something for you....
from ^^ article, there is a good basic explanation:
"Our English friends call a shock absorber a dampener, which may be a better name, because its job is to dampen the oscillation of the spring. The spring controls and absorbs road shock and vehicle weight transfer, not the shocks."
So, the dampener, "shock", dampens the movement of the spring up and down by taking the kinetic energy as it moves and forces air or oil through a small hole inside, converting kinetic energy to potential energy (when the shock is in the compressed state) and heat energy (the air/oil heats up when forced through the valve)
The spring, however, absorbs the "bumps" that the car receives from the road. It takes in energy as the suspension compresses and outputs opposing energy (spring force against compression) in order to return to equilibrium.
The crank can be looked at in the same light. The snout of the crank vibrates in any of the 360 degrees around it, so the rubber ring on the crank pulley is like a spring in the suspension. Is it obvious now that it doesn't matter where this rubber ring is located? Think about it in suspension terms, it doesn't matter what unsprung weight there is in between the spring and the road, the spring is still going to do its job. As long as it has metal attached to the inner and outer sides of it, it is going to absorb vibrations, so not that this would be a reality, but a concentric rubber ring on the flywheel would do the same thing.
The main difference is in how the energy is output once received. Both absorbers and dampeners receive energy in the same manner. An absorber takes that energy and outputs it in the same form. A dampener in effect takes the received form of energy out of the system, by converting it to another type of energy. The fluidamper takes in vibrations, coverts them to heat, and then dissipates the heat into the ambient air in the engine bay.
I'll look for a wikipedia article or something for you....
12-14-2006, 08:03 AM
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Listen up students..Matt's holdin session
here's some good links off of ati's website
http://www.atiperformanceprodu...x.htm
one by Dinan's founder:
http://www.atiperformanceprodu...n.htm
some dyno testing:
http://www.popularhotrodding.c...dsor2/
here's some good links off of ati's website
http://www.atiperformanceprodu...x.htm
one by Dinan's founder:
http://www.atiperformanceprodu...n.htm
some dyno testing:
http://www.popularhotrodding.c...dsor2/
12-14-2006, 08:06 AM
#13
thanks brosef
a good quote from the third article:
"Even for a drag racer, where acceleration is all that matters, a functional damper will out perform a light, non-functional one every time."
a good quote from the third article:
"Even for a drag racer, where acceleration is all that matters, a functional damper will out perform a light, non-functional one every time."
12-14-2006, 01:47 PM
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hha i'm so glad everyone is finally coming to this conclusion after I got bashed about it not even a year ago..like Honda's are some special engine breed whose cranks are divine
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