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The Harmonic Balancer Thread


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The thread on the crank sprockets (http://www.ultimatesubaru.org/forum/showthread.php?t=69210) has sparked a question in me. Why did Subaru feel that it was necessary to have a harmonic balancer pulley on the Turbo EA82? The NA EA82 just has a regular pulley to drive the accessories.

 

I believe the harmonic balancer, is actually a dampener, to dampen the shocks from the engaging AC compressor to the crankshaft.

 

the reason why NA ea82 don't have them, I don't know, perhaps you looked at a non AC?

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The thread on the crank sprockets (http://www.ultimatesubaru.org/forum/showthread.php?t=69210) has sparked a question in me. Why did Subaru feel that it was necessary to have a harmonic balancer pulley on the Turbo EA82? The NA EA82 just has a regular pulley to drive the accessories.

 

Probably because the higher power engine has more intense harmonic vibrations.

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All Turbo models had the balancer, A/C or not.

 

Are there any ill effects if you swaped the balancer/dampener pulley for a regular pulley on a turbo EA82 engine? (Obviously reasons for doing this is to reduce rotating mass like that of lightening the flywheel.) I figure there may be long term effects. The main bearings may wear faster.

 

How many out there have swapped pulleys without problems and how many miles have you put on it?

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Not worth the trouble - you wouldn't gain even .5 HP from it.

 

Lighten the flywheel if you want to do something productive.

 

GD

 

Been there, done that. I have a XT6 flywheel with 6 pounds removed. But is that all it will gain? The harmonic balancer pulley is pretty heavy. I would think putting on a SPFI pulley would give it maybe 5hp. Or it should at least make it rev faster.

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I don't think there's much difference in weight frankly with the SPFI pulley. It's actually pretty heavy.

 

Each pound on the crank is like 2.7 HP.... but unless you go with aluminium, I doubt you would gain much.

 

Then there's the alignment issue.... doesn't the turbo use a different hub depth for the water pump? I don't think the SPFI pulley would line up.

 

GD

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I ran one on my Rx... There was a slight increase... but hey for the $0 I paid for the pulley, it was worth it... The car seemed to rev a bit quicker, and actually I have an aftermarket pulley on my XT-6 which was actually 6 lbs lighter then stock and I noticed the same reaction. As far as the belt alignment... It is off, but this is also a V belt... its not that big of a deal, its only like 1/8" off...

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1- lightening flywheels and the like do not give you any more hp, as long as the center of mass of the item is on the crankshafts axis of rotation. The only effect it has is to lower the reisitance to acceleration.

 

2- Since rotational inertia varys with the square of the radius, a small item like a crank pulley will have very little effect on the total rotational inertia. The flywheel has so much more rot inertia than the crank pulley to make the pulley negligible. Don't waste your time.

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