crank pulley issues

[Trevor]

I am not going to get into an argument here. Seat of the pants analysis and after spending money expectations, will always inflame the issue.

However have those who install lightweight crankshaft pulleys, based on the theories of those who sell them, really thought out what is the total reciprocating weight, in respect of a road going engine with driven accessories. The possible reduction in inertia, by reducing the weight of such a small diameter component is so minimal as to be not worth considering. It is not a wonder that the after market trade, offers pulleys in a pretty anodised finish.

The valid argument against this modification, is that Subaru fitted a torsional vibration damper for a reason. Were and are they fools to incur reduced performance at additional cost?

[Landshark]

Originally Posted by Trevor

I am not going to get into an argument here. Seat of the pants analysis and after spending money expectations, will always inflame the issue.

However have those who install lightweight crankshaft pulleys, based on the theories of those who sell them, really thought out what is the total reciprocating weight, in respect of a road going engine with driven accessories. The possible reduction in inertia, by reducing the weight of such a small diameter component is so minimal as to be not worth considering. It is not a wonder that the after market trade, offers pulleys in a pretty anodised finish.

The valid argument against this modification, is that Subaru fitted a torsional vibration damper for a reason. Were and are they fools to incur reduced performance at additional cost?

all i know is, that mine revs up much quicker, which was noticeable especially when using the Sportshift and .... whoa! i came close to bouncing off the rev limiter! many have used them with no reported cases of failure. there have been cases of the stock pulley separating and failing, however. i will probably keep this car for about 5-6 years (will have ~ 50k-60k by then), so i'm not worried. how it affects the long term, 100k+ mileage engine life, i don't know ......or need to worry about. they are cheap enough to not be a big deal of gain vs. price, but i'd say its a good bang for the buck.

[NikFu S.]

Stock pulleys fail just as often as aftermarket, but mine is more for looks than anything.
In any case there is no hard evidence lightweight pulleys are less reliable than harmonic balancers.

You are right, though, considering the tiny weight of a pulley and the huge power of this engine, you won't see any performace gain, but it does compliment a full system of lightened powertrain/drivetrain parts to a degree.

It more or less boils down to a compulsion to make something ones own, a little closer to unique. (:

[Landshark]

Originally Posted by NikFu S.

Stock pulleys fail just as often as aftermarket, but mine is more for looks than anything.

find me evidence of a stock-sized lightweight pulley EVER failing or causing a problem.

You are right, though, considering the tiny weight of a pulley and the huge power of this engine, you won't see any performace gain, but it does compliment a full system of lightened powertrain/drivetrain parts to a degree.

if they are completely useless, then why did SPT (Subaru Performance Tuning) use GFB lightweight pulleys (underdriven ones, no less) on their Legacy GT project car?

[NikFu S.]

1) My stock sized red pulley failed, caused all kinds of drama.

2) I didn't say they were useless, I said they won't give you a noticable power gain unless used on concert with other parasitic loss reducing components.

(:

Notice however in your pic they are labeled as underdrive (oh, you noticed (; ). They are not convinced light weight alone is enough of a gain.

[Landshark]

Originally Posted by NikFu S.

1) My stock sized red pulley failed, caused all kinds of drama.

your piece-of-junk-ebay-most-likely-not-even-the-right-size pulley failed.
different situation.

2) I didn't say they were useless, I said they won't give you a noticable power gain unless used on concert with other parasitic loss reducing components.

agreed, however it will rev noticeably quicker.

Notice however in your pic they are labeled as underdrive (oh, you noticed (; ). They are not convinced light weight alone is enough of a gain.

right, but i didn't want to deal with lowered AC compressor or alternator output and have to change to different belts on my daily driver. that is fine for a PROJECT CAR. i was in it for the quicker revving, which is more desirable in a turbocharged vehicle. for a high mileage SVX, its cheaper than a stock pulley replacement, you'll get a little quicker rev, and no explodering pulleys in teh yu0r engine bay.

[NikFu S.]

Originally Posted by Landshark

your piece-of-junk-ebay-most-likely-not-even-the-right-size pulley failed.
different situation.

True I guess, but I do recall someone within the last month or so had a similar problem and posted pictures. It had wobbled slightly and eventually eroded the key slot and this person was unable to remove the key. Factory pulley.

So far that's one for oem and one for aftemarket.

[Trevor]

if they are completely useless, then why did SPT (Subaru Performance Tuning) use GFB lightweight pulleys (underdriven ones, no less) on their Legacy GT project car? [/QUOTE]

Because they wanted a pulley of smaller diameter, so as to reduce the drive ratio to the driven accesories, to reduce power losses in view of increased RPM.

[Landshark]

Originally Posted by Trevor

Because they wanted a pulley of smaller diameter, so as to reduce the drive ratio to the driven accesories, to reduce power losses in view of increased RPM.

i was mainly referring to the fact that there is no rubber dampener/balancer.

[Trevor]

Originally Posted by Landshark

i was mainly referring to the fact that there is no rubber dampener/balancer.

Fair enough but I wonder what sort of warranty they offer on their copleted offering. The damper was not put there as a joke.

[Landshark]

Originally Posted by Trevor

Fair enough but I wonder what sort of warranty they offer on their copleted offering. The damper was not put there as a joke.

probably none - that was a project car. i've seen e-mail replies from Subaru stating that the stock pulley is not a harmonic balancer. i don't know what actual purpose the rubber serves - reducing NVH?

from what i've seen, WRX's that use a lightened flywheel AND crank pulley can throw CEL's, but i've yet to see any trouble/failure from a lightened stock sized pulley alone.


BTW....good to see you back, Trevor. hope all is well with you.

[Trevor]

Originally Posted by Landshark

probably none - that was a project car. i've seen e-mail replies from Subaru stating that the stock pulley is not a harmonic balancer. i don't know what actual purpose the rubber serves - reducing NVH?

from what i've seen, WRX's that use a lightened flywheel AND crank pulley can throw CEL's, but i've yet to see any trouble/failure from a lightened stock sized pulley alone.


BTW....good to see you back, Trevor. hope all is well with you.

This is a very interesting subject. The auxiliaries are flexible belt driven and this medium must introduce a connection which in itself is an excellent absorbent of erratic torsional forces. I wonder if the engineers involved restricted their thinking to the engine only and disregarded all else.

[Landshark]

Originally Posted by Trevor

This is a very interesting subject. The auxiliaries are flexible belt driven and this medium must introduce a connection which in itself is an excellent absorbent of erratic torsional forces. I wonder if the engineers involved restricted their thinking to the engine only and disregarded all else.

you lost me - i on (potent) beer #6

[Trevor]

Originally Posted by Landshark

you lost me - i on (potent) beer #6

Bloody good one Alan. I am on a potent home brew. Think about flexible belts, not the garter variety, and how they strtc-----h. Belt driven cam shafts have the same advantage in respect of torsional damping. But what the hell, drink your beer!!!!

Cheers, Trevor. *<)

[intelisevil]

Originally Posted by Trevor

This is a very interesting subject. The auxiliaries are flexible belt driven and this medium must introduce a connection which in itself is an excellent absorbent of erratic torsional forces. I wonder if the engineers involved restricted their thinking to the engine only and disregarded all else.

You speak purtier than a two bit w.h.o.r.e . . .

Dan

PS: Sort of quoted from the movie Blazing Saddles.