brens.scoob

iTrader: (1)

are the lightweight pulleys worth getting?

torn between the rcm or cdf,cdf are £100 cheaper.

anyone have either fitted?did you notice any difference,surely they will make a difference wont they.

cheers.

L.J.F

iTrader: (31)

I had lightweight pulleys and flywheel which really makes a improvement to how the revs pick up and so much more responsive.


Worthwhile mods in eyes.

Blue by You

iTrader: (23)

Why fit a lightweight pulley and remove the vibration damping benefit of the OEM pulley?
Not to mention the imbalance it will create on any centre thrust crank engine.

tubbytommy

iTrader: (20)

+1 fit it because its shiny

brens.scoob

iTrader: (1)

They say you dont need the dampers for the vibration due to the lightweight. 255g compared to the 2500g std pulley.

Ashp1989

iTrader: (1)

When I spoke to Brian at cams in Blackburn he reccomended the lightweight pulleys and removing the air con. Said it will be a lot more responsive. So I purchased some lightweight pulleys off him, bought myself a oil catch can as he also told me I should be running a catch can with a fmic.
Pulleys not fitted yet, and air con hasn't been removed. Will be getting done soon when I can be bothered.

Surely if pulleys were even the slightest going to cause any damage he wouldn't reccomend them?

lordharding

iTrader: (1)

They look nice

Greenwagon is going on holiday to be pampered

Blue by You

iTrader: (23)

So Subaru spend millions of dollars developing their cars (as do other makers) and include a bonded rubber insert in the crank pulley to absorb harmonic vibration, and it's ok to just discard that in favour of a pretty piece of bling?

This is an extract from a document posted on 22B, written by the Engineers at Fuji Heavy Industries (Subaru) for the SAE.



Furthermore the weight of the cast iron pulley serves as a counterweight for the clutch/flywheel mass on a centre thrust crank engine.

If you're going to modify something at least be aware of the possible consequences.

What price a bit of bling?

trails

iTrader: (41)

^^^this is the truth. Everything else is BS.

tubbytommy

iTrader: (20)

+1 the other pulleys should be fine though

thenewgalaxy

I would love to see the engineers report on the materials and parts used for the stock 2.5 engines, along with their justifications for using them.

rooferman

iTrader: (6)

The adjustable option is the only reason for these afaik.

jaygsi

iTrader: (46)

I'm getting my cambelt changed soon and was going to get lightweight pulleys, while i'm at it, guessing i should fit OEM after reading this?

trails

iTrader: (41)

yes go OE and if you fancy a hunt there is a rare sti specific pulley too

53

iTrader: (41)

I didn't bother with the pulleys either LWFW is a good modification but I couldn't see the benefit in messing about further

JDM_333

Good info in this thread - thanks, I too was considering dropping light weight pulleys in but after reading the attachment above (thanks BBY) I'll stick with the OEM.

CDF Racing

iTrader: (49)

So so many rumors about these lightweight pulleys, but how many can say they have seen one of our pulleys fail or cause any damage to engine bearings ? None at all ...

The document above was actually made in the 80's .. not sure if you knew that.

The Subaru engine is self-balancing , thus does not require a harmonic damper.

This was a reply a guy had over on Nasioc :

Thanks for reminding me of nasioc, I just did some searching and came up with this, a reply by GT2RS in a thread discussing this very issue:

"I finally got an answer directly from Subaru of America...I asked them if the crank pulley for the WRX and the STi is used as a harmonic damper/balancer. Here's the reply...


Hello F. Flores:

Thank you for your patience as I checked with our Technical Services
Department regarding your message below. They advised that the crank pulley
is a pulley and nothing else. It is not used as a harmonic damper/balancer.

Thanks for the opportunity to be of assistance. If you need any future
assistance, please feel free to contact us again.

Best wishes,

John J. Mergen
Subaru of America, Inc.


I think this topic can now end!"

We have been making these stock size pulleys for near on 10 years now.... without one fault or problem, i even run them on my car - as well as hundreds of scooby netters.


I think some issues may of been caused by poorly made Chinese under driven (not stock size) pulleys


I offer a LIFE TIME warranty as long as you own the car with our pulleys because I know - for fact they will cause no issues, you will only gain from these... any have the peace of mind that a heavy steel pulley isn't going to split in two and make a large bang under your hood .

joshnosh

iTrader: (1)

which pullys have the dampers
camshaft ones? alternator? ancillary drive?

trails

iTrader: (41)

Not knocking your product Chris, or your warranty but I think in this instance you are incorrect; from Subaru technical journal;

"A double mass harmonic balancer is adopted to disperse the torsional and bending vibration up to the 7500 maximum operating speed”

Which also explains why the sti pulleys have a larger damper because of of raised rev limit.

Blue by You

iTrader: (23)

I am aware of the history of that document Chris, but the basic engineering premise of Torsional Harmonic Vibration is no less relevant because of that.
Nobody has made any defamatory or otherwise critical remarks about your products on this thread, so your perhaps indignant defence smacks of vested interest a little IMO.
Furthermore your statement that "The Subaru engine is self-balancing , thus does not require a harmonic damper." is fundamentally incorrect.
Have a read of ATI's discourse on Harmonic Dampers here http://www.atiracing.com/products/da...mper_dinan.htm

Of particular relevance is this paragraph - "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."
How is a Subaru engine immune to these vibrations that affect all other crankshaft installations?

I'm not trying to teach you to suck eggs Chris. People will buy your products based on your good reputation and expertise. But you can't justify use of your product by simply saying that torsional vibration does not exist in a Subaru engine.
Steve.

Blue by You

iTrader: (23)

Crankshaft.

Ren77

iTrader: (4)

Anyone interested may wish to refer to this thread:

http://bbs.22b.com/forums/showthread...armonic+damper

Chris, just because that paper was written in the 80s does not make it wrong.

Newton's laws of motion were published in the 1680s, so by your logic these must be very wrong by now...

The opinion you have solicited from SOA is incorrect, there is no debate, it is incorrect. How is the person mentioned qualified to give this statement?

Please can you post to confirm this on both threads.

trails

iTrader: (41)

I knew I should have searched of 22b first, end of thread

CDF Racing

iTrader: (49)

Ian, Steve ..

No problem at all,

My point I am trying to make is that from my experience - If you use a a well made pulley, whether it be one of ours, Rcm, Perrins or whoever then you will have no issues.. I can say this in confidence because of the amount we have made and zero reported issues.
Maybe if you was replacing with another heavy steel pulley without a rubber bonding or poorly made our of balance pulley then yes I could see the bearings not lasting very long at all..

Ren,. I'm definitely not getting into a debate with you,. Zen has had a problem with us from day one,. and I have no idea why. I saw your comment on 22b about "shows what we know" about pulleys because I told a customer to use a newage pulley on a classic car - at first he told me he had a sti 8- so that's why I told him that.

Ren77

iTrader: (4)

There is no debate here. I note you do not address the posts, or PMs on 22b.

There is no problem with the CDF pulley, but the advice you are giving is not correct

Are you prepared to admit that the stock front pulley is a harmonic damper?

Blue by You

iTrader: (23)

Thanks for your response Chris, and seeing my comments in the way they were intended.
I can't help but agree there are a great many lightweight aftermarket crankshaft pulleys made by various manufacturers spinning away on Subaru engines all over the world.
However you haven't addressed the essential point I was making that HTV does exist in a Subaru engine, and that your comment
is misleading.
This is not concerned with dynamic balancing that most people are familiar with.
Vibration Dampers of the kind fitted to the Subaru EJ series engines are designed to deal with vibrations that are an inherent feature of the vast majority of internal combustion engines, and as described in my post #20, nothing to do with balancing.

trails

iTrader: (41)

no beef here Chris, you have always helped me out when you could, just the facts aren't there...simple physics really

CDF Racing

iTrader: (49)

Yes Steve, sorry I may have jumped the gun with that statement , yes it does exist as clearly shown on the drawing.. BUT my point "believe" is that it is not required on this engine .....that is why is it ok - safe to run a lightweight pulley

Harmonic damper
From Wikipedia, the free encyclopedia
A harmonic damper is a device fitted to the free (accessory drive) end of the crankshaft of an internal combustion engine. It is essential in engines with long crankshafts (such as straight-8 engines) and is present on most engines as it reduces torsional vibrations that tend to peak at certain speeds. Torsional vibrations can greatly reduce crankshaft life, if not cause instantaneous failure, if the crankshaft runs at or through resonance. Because of this, dampeners are designed with a specific weight and diameter to reduce mechanical Q factor, or dampen, crankshaft resonances. Factory dampeners are often re-sized in the same basic engine with any factory modification of crankshaft material, thickness, weight, or throw.


I believe it is actually safer to run a well made solid aluminium pulley



Ren, you may not of noticed but I am not an active member on 22b so i haven't even see your pm - you can see the last time i logged on was before you sent me a message

Ren77

iTrader: (4)

What on earth are you basing this belief on?

CDF Racing

iTrader: (49)

Because we have replaced lots of stock pulleys that have broke in two pieces , some causing damage to the crank shaft and casing

and replaced zero aluminium pulleys because they have broke