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Reason
01-06-2006, 08:19 AM
It's almost time for new belts. So mine as well get new pulleys :wink: So I'm torn between a Perrin crank pulley (stock diameter) of a GFB pulley set (under driven). Let's start a debate on which is better and worth it. I'll take any gains I can in torque and horse power.

Wiscon_Mark
01-06-2006, 09:05 AM
just go lightweight, saves a lot of trouble getting belts, and you get the same power from your alternator and other belt driven accessories.

Reason
01-06-2006, 09:28 AM
I need new belts anyway, plus the GFB pulley set comes with belts.

Huffer
01-06-2006, 11:28 AM
Go lightweight, not underdriven. Not worth the potential hassles.
T-belts etc are cheap from the dealer. I think $9 or so dollars.

GFB also make a lightweight version, as well as underdriven.
(I have one, not installed. I could be persuaded to sell it... ;) )

gator gt
01-06-2006, 01:31 PM
I have an Unorthadox Racing crank pulley. lightweight and underdriven. off of car (has been for sometime now) and ready to go.

It came on the car from the original owner.

It is black anodized aluminum...but there is some light damage to the belt grooves...but does NOT harm the belts. It is still fully functional. Happened when I used a chain wrench to remove it. (<--- tech's suggestion! :evil: )

If when I inspected it, it looked to harm the life of the belt, I'd have tossed it into my dad's aluminum pile for recycling.

Why did I take it off? I disliked the dimming of lights from the underdriving of the alternator; and not only did the lights dim at a stop light.....the rest of anything that needs juice dimmed: interior lights, HVAC fan, etc.

I think they go for $170+ new....this can be someone's for $80 shipped. Reason has first dibs since this is HIS thread....but if he rejects, first come first serve. PM please.

According to the website, this is good to use on:
• 03-05 Baja 2.5L
• 98-05 Forester 2.5L
• 93-97 Impreza 1.8L
• 95-05 Impreza 2.2L
• 98-05 Impreza 2.5L
• 90-99 Legacy 2.2L
• 96-05 Legacy 2.5L All
• 00-05 Outback 2.5L
• 92-97 SVX 3.3L
• 02-05 WRX 2.0L Turbo
• 04-05 WRX STI 2.5L Turbo

...hmmm, almost looks like the entire Subaru lineup. :lol:


Pic from website of current line (known as underdrive Ultra S):
http://www.unorthodoxracing.com/Merchant2/0213101.jpg

Mine doesn't have the holes, but is shaped in the same manner. The other style is the Tuner Series....mine is NOT that one.

GGT

Plays_with_Toys
01-06-2006, 01:53 PM
From what I've read, I'd rather go just lightweight. I've read the underdriving is just not suited for anything but racing (where its not necessary to run accesories, music, or lights). If you go with just the lightweight perrin unit, then you can just go to any auto store and get belts.

Another thing to consider is how much it under drives the assembly. The more underdrive (smaller diameter pulley) the less your alternator is cranking, but there are some pulleys which are just slightly smaller.

Even after that, the minimal gains of power available from underdriving are generally not worth the electrical hassle.

Reason
01-06-2006, 04:35 PM
Good stuff guys, I think I will go with the lighten crank pulley. Anyone know if a company makes lighten alt and PS pulley? I know Unorthodox makes those pullyse, just not sure if they are stock size or not.

Huffer
01-06-2006, 04:53 PM
A quick note too:

The stock pulleys also perform the dual role of harmonic dampning. Without them, expect an increase in NVH. Particularly with the crankshaft pulley, as it's the biggest.

The other pulley's won't net you any real "gains" - most of the gains are in weight savings, and are usually the last things most competitive cars do. Although these days, with the availability of parts, they're often one of the first.

Reason
01-06-2006, 05:11 PM
So who has this so they can tell me what to expect??

Plays_with_Toys
01-06-2006, 05:39 PM
Huffer, I've read several threads that state that on subarus, the pulley is not a harmonic balancer, including a thread which had a response from Subaru of America stating so.

Its been said you don't "gain" horsepower, but instead, HP is distributed better. Instead of needing power to move a heavy pulley (lots of rotational mass), you are now using it elsewhere. Its like running lightweight wheels. You lose that mass, so the power accerates you more easily. Your engine should slow down quicker off of throttle as well since you have less mass keeping it rotating. Also revs will be quicker.

belladonna
01-06-2006, 08:49 PM
i would like to see the harmonic dampening article you have Huffer...i've always though they were harmonic as well :?

i'm with the majority on this one shane...go lightweight and not underdriven

Perdue
01-06-2006, 11:36 PM
PCM (I think that's the company name) makes a 3 pulley set for our cars that is only lightened, not underdriven. I'd see if I could find a set of those.

Huffer
01-07-2006, 01:14 AM
Huffer, I've read several threads that state that on subarus, the pulley is not a harmonic balancer, including a thread which had a response from Subaru of America stating so.

SOA posted on NASIOC? As in, an actual representative, not a dealership parts salesperson?

That's a huge departure from company policy - and would probably never be endorsed at an official "Technical Bulletin" level.

There will be threads either way. My own personal thinking is that the stock item is a specific size and weight as a result of a manufacturer compromise in terms of weight, durability and cost.

Why wouldn't it be a harmonic damper - it's big, heavy and we know the H4 is a fairly unstable beast, rocking back and forth a lot.

Larger, HEAVIER objects are always hard to move, and they also resist vibrations (which are essentially kinetic soundwaves). Of course, there's no sound in a vacuum, so... ?

It's a moot point really. Every person I've ever talked to who has had a crank pulley on an EJ series engine tells me they get more NVH.

Some of those people also state that they didn't notice the different between stock tranny mounts and STi ones. Others went back to stock mounts because of the NVH.

Grain of salt for this type of discussion, really. ;)

Bella - I don't have an article handy - but like PWT, I read several threads (not 100% related to Subaru's either) about the harmonic damping characteristics of crank pulleys.

strat81
01-07-2006, 02:28 AM
as huffer said, you get most of your gains from lightening...

also, in severe cases (i personally have only ever read about this as a "worst possible case"), with the lack of a harmonic damper, you can wear out crank bearings and such due to the lack of damping on the crank. the article i read in one of the tuner mags suggests having the rotating assembly (crank/pulley/flywheel) balanced to help eliminate any problems. that being said, again, i have NEVER seen anybody have problems running a different crank pulley. (i run a lightened one on my cavalier with no problems)

something else to keep in mind... with the lack of weight, your revs will climb quicker when accelerating and drop quicker when shifting gears but you will also have a bit less engine breaking when downshifting. (all of this assuming you have a manual)

my .02

Plays_with_Toys
01-07-2006, 03:26 AM
Huffer, SOA did not post, but a person on nasioc emailed SOA and received a response saying something to the effect "Sorry for the delayed response but I had to check with the engineering department before confirming that the crank pulley on EJ series motors is not a harmonic dampener."

The email was then posted on nasioc. I read about pulleys for like 4 hours in a row on nasioc. Almost no one reported negative effects, only like 2. All they said was that the engine ran a little rough. But that was 2, out of hundreds.

Forgive my ignorance, what is NVH?

Sarra
01-07-2006, 04:51 AM
increase your stroke, and put an overdrive pulley on?

I'd say stock diameter, but lighter. That's what I eventually hope to do myself.

Wiscon_Mark
01-07-2006, 12:52 PM
Its been said you don't "gain" horsepower, but instead, HP is distributed better. Instead of needing power to move a heavy pulley (lots of rotational mass), you are now using it elsewhere. Its like running lightweight wheels. You lose that mass, so the power accerates you more easily. Your engine should slow down quicker off of throttle as well since you have less mass keeping it rotating. Also revs will be quicker.

That's the idea with most mods. The engine isn't actually producing more HP, the only way you can do that is by forcing more air and gasoline into the cylinders at once, but you're putting more of your power to the wheels.

Reason- I think it would give you a slight gain on the butt dyno.

Huffer
01-07-2006, 02:19 PM
Huffer, SOA did not post, but a person on nasioc emailed SOA and received a response saying something to the effect "Sorry for the delayed response but I had to check with the engineering department before confirming that the crank pulley on EJ series motors is not a harmonic dampener."

The email was then posted on nasioc. I read about pulleys for like 4 hours in a row on nasioc. Almost no one reported negative effects, only like 2. All they said was that the engine ran a little rough. But that was 2, out of hundreds.

Forgive my ignorance, what is NVH?

Ahh, I see. Well, there's no reason someone couldn't forge an email. :P
It also depends on what someone considers a "harmonic damper" - an engineer might say a damper is something that actively absorbs and transforms kinetic energy into heat...and thus a crank pulley isn't designed to convert kinetic energy, therefore it isn't a damper.
But I'm being picky.

NVH = Noise Vibration Harshness - I think. Anyway, it basically means noise.

jey
01-07-2006, 02:48 PM
If the crank pulley doesn't have a harmonic dampener, then why is there a big ring rubber section in the middle of it?

Huffer
01-07-2006, 06:12 PM
^^ No - we're talking about the crank pulley BEING the harmonic damper - as in, the entire thing. Not part of it.

If you check out the GFB type replacements, they're just anodized alloy - no rubber bit.

Plays_with_Toys
01-07-2006, 08:26 PM
Huffer, what jay is saying, is that because there is a rubber core inside of the pulley, it is a harmonic dampener.

Huffer
01-07-2006, 09:16 PM
I know that, but you just said it isn't. :P

Plays_with_Toys
01-08-2006, 12:39 AM
Oh, I am in no way endorsing what he says. Its the first I've heard of a rubber core.

jey
01-08-2006, 11:11 AM
http://www.jeyping.dynip.com/journal/images/pulley1.jpg

Ok, I guess my question is, being more specific with a picture now, what is that ring of material in my stock pulley? One would think it should be all made out of 1 material like all those aftermarket pulleys for simplicity sake.

BAC5.2
01-09-2006, 09:42 PM
Concern for NVH means you should stick with the stock stuff.

Most mods worth something will cost you NVH. Look at my Legacy. NVH out the wazoo, but it keeps up with STi's, and is infinitely cooler.

Official stance? No Underdriven. Under driving the alternator will cause ALL kinds of problems with the car. If you have an older, weak alternator, you'll misfire and sensors will malfunction from lack of voltage.

Plays_with_Toys
01-09-2006, 10:07 PM
Brand new alternator for me :-D Did the alternator recall stretch out to your car Reason?

Reason
01-10-2006, 04:03 AM
Brand new alternator for me :-D Did the alternator recall stretch out to your car Reason?

Yea they replaced it about 3-4 years back. I'm just going to get a Perrin. I finally decided what I'm going to do with my car. That engine won't be in there for ever :wink:

subieyacht
01-14-2006, 06:30 PM
i have a perrin lightweight one, and i love it. my buddy has the unorthodox set on his rs and he says he has all kinds of problems, and thee steering feeels like crap too, so i think lights weight is the way to go

Reason
01-14-2006, 07:59 PM
i have a perrin lightweight one

Me too :D

HFSDevil
01-14-2006, 10:18 PM
I got the Mr. Josh pulley for my car. Love it.

http://www.mrjosh43.com/tpi/home.html

dropdfocus
01-21-2006, 12:05 AM
I installed the Perrin pulley on the wife's '98 2.5GT and the response under full throttle is much more increased. I ordered it from RalliTek & I got it in 2 days. It took about less than an hour to install with air tools. Then another 30 minutes of driving around & working out the air in the cooling system. Well worth the money spent & the short amount of time for installation.

strat81
01-21-2006, 12:36 AM
jason... glad to see you on sli 8)

Plays_with_Toys
01-23-2006, 03:00 AM
Air in the cooling system? An unrelated problem to the pulley install or direct result from the install? Had never heard of this problem before.

Reason
01-23-2006, 11:13 AM
Air in the cooling system? An unrelated problem to the pulley install or direct result from the install? Had never heard of this problem before.

Never heard myself. Explain yOseLf FoO