Lightweight crank pulley

[wootwoot]

Originally Posted by stugray

If you look closely at the factory pulley you will see a hole machined into it near the perimeter on the front.
My assumption is that this hole is put in place when the rotating assembly is balanced at the factory.

Why would anyone want to upset the factory balance for a imperceptible increase in HP or a negligible decrease in rotational inertia?

NOW if I was to build an engine from the ground up I would definitely put in a lighter pulley AFTER a lightened flywheel & clutch, lighter Con rods, pistons, and possibly lightened crank (the pulley has the LEAST effect on rotational mass of any of those other things) THEN I would have the entire rotating mass balanced.

If I remember right, I think the pulley is balanced individually and then installed on the crank afterword. If you look at the crank pulley it has small dimples drilled in it to balance it out. This is necessary as it is a rather crude cast part. People thought they were timing marks for a while until this was figured out.

[Trashed675]

I had a lightweight crank pulley on my 06 tC for about 70k miles before trading it in for the FRS. Likewise my brother has had a perrin pulley on his 09 STi basically since the day he bought it new in 09....no problems. Stop your worrying people.

[wootwoot]

http://forums.nasioc.com/forums/show....php?t=1599089

Good read...

[wootwoot]

From the thread I linked:

"For what it is worth,
We only run harmonic balancers on all of our street and race motors.

The benifit of a lighter pulley does not offset the long term damage that it causes, sorry.

Quirt Crawford
www.crawfordperformance.com"

And then you have this:

Per

http://www.unorthodoxracing.com/faq_pulleys.html

"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."

[Apoc]

Originally Posted by wootwoot

http://forums.nasioc.com/forums/show....php?t=1599089

Good read...

All I see is the same arguments from 2009. You would have thought that the vendors would have stopped making these dangerous pulleys once they caused all those boxer motors to vibrate to pieces.

Oh wait here's an even older post from 2003. I think we should debate this for another 10 years

http://forums.nasioc.com/forums/show...hreadid=444518

[mike_ekim1024]

There are so many options now: Buddy Club, Raceseng, Go Fast Bits, etc. Looks like Raceseng also makes the idler pullys which ties them all together visually. I know these work on autos, but I'm just wondering if it will mess with shift timing or rev matching, making it jerky or not coordinated well.

[wootwoot]

Originally Posted by Apoc

All I see is the same arguments from 2009. You would have thought that the vendors would have stopped making these dangerous pulleys once they caused all those boxer motors to vibrate to pieces.

Oh wait here's an even older post from 2003. I think we should debate this for another 10 years

http://forums.nasioc.com/forums/show...hreadid=444518

What's your point? There are topics people have been debating over for centuries. How old a particular discussion is has nothing to do with how relevant it is. Until a definitive answer is found the debate will continue. So here we are.... These threads, despite being old, still have good information in them which is why they are being posted here.

[stugray]

I made all of my points on this thread:

http://www.ft86club.com/forums/showthread.php?t=50879

No need to re-post my opinion.

[86-tundra]

Anyone know of a video showing the differences in rev speed with stock and lightweight pulley?

[stugray]

Originally Posted by trevorovert

Anyone know of a video showing the differences in rev speed with stock and lightweight pulley?

See the link I posted above.
There is a video there but it is inconclusive because there is no way to know if the operator applied the throttle exactly the same both times.

[86-tundra]

Originally Posted by stugray

See the link I posted above.
There is a video there but it is inconclusive because there is no way to know if the operator applied the throttle exactly the same both times.

I saw that, but the video only showed the response with the pulley installed.. not with and without.

[stugray]

Originally Posted by trevorovert

I saw that, but the video only showed the response with the pulley installed.. not with and without.

No that is both. The red needle is the Worx pulley and the green needle is the OEM pulley.

[phanguy]

if Subaru themselves said that it doesn't matter then i'm inclined to agree... but for the sake of argument is there time that a company has said that a part could be changed out without worries then someone does it and their car has a meltdown? i don't have enough knowledge of all that so i'm just putting that out there. cause if subaru has made statements before and consumers/drivers unfortunately proved them wrong then i can see why people would still be skeptical.

on the other hand is there any chance someone is willing to try to reach out to the actual subaru president or one of the engineers that worked on the car? i mean why not?

[wootwoot]

I sent an email to Subaru, Perrin, Cosworth, Litchfield, AWD tuning, Cobb, Element, and a few others. I will let you guys know if I get any interesting responses.