Lightweight crank pulley

[stugray]

Originally Posted by Turdinator

Can we all just agree that lightening the rotating mass on an engine is good unless you are partial to revving it up and dropping the clutch.

No. As I stated before: IF the rotating mass is balanced at the factory, then changing the pulley will throw off this balance.

If you want to shed a couple of pounds from your car, why dont you just remove the wheel balance weights. That is even un-sprung weight!

[OICU812]

There has now been two official statements by manufacturer themselves saying the LWPs are perfectly fine with our engine So..... Why are some still even trying to discredit?... Seems senseless is all?

[mike_ekim1024]

Originally Posted by stugray

No. As I stated before: IF the rotating mass is balanced at the factory, then changing the pulley will throw off this balance.

If you want to shed a couple of pounds from your car, why dont you just remove the wheel balance weights. That is even un-sprung weight!

I can't confirm, but didn't someone say the pulley was self balanced, like why wheel weights are used? Not balanced to the engine itself? It's a cheap part... Is it perfectly balanced right out of the mold?

[Turdinator]

Originally Posted by stugray

No. As I stated before: IF the rotating mass is balanced at the factory, then changing the pulley will throw off this balance.

If you want to shed a couple of pounds from your car, why dont you just remove the wheel balance weights. That is even un-sprung weight!

Our engines are not externally balanced. If you google external and internal balancing you'll read how some engines (generally large pushrod V8s) are externally balanced by offset weights on flywheels and harmonic balancers. 90% of engines are internally balanced meaning each part of the rotating assembly attached to the crankshaft (and the crankshaft itself) are individually balanced. With internally balanced engines as long as you replace the flywheel with another balanced flywheel you won't be effecting the engines overall balance. If I had plans to replace my front pulley I would be spending the $20 - $50 it cost to get it balanced by a machine shop for peace of mind.

What you should be more concerned about are crankshaft harmonics which are completely different to its balance. The stock pulley may be a harmonic damper or it may just have that layer of rubber just for NVH reasons. I personally have driven an NA 70s inline 4cyl Toyota engine with nearly double the stock power for over 60,000kms with a solid crank pulley without any issues to date. So I am not too concerned about the effects of replacing the front pulley on my FA20. If you are then great, don't buy one.

[stugray]

I build 4-cyl Boxer engines for racing. I have the rotating assembly balanced by a pro.
My engine has a "pulley" on the front.
When the machinist balanced the rotating assembly he had to drill holes in the front pulley as well as the flywheel.

If I change the flywheel or the front pulley I have to rebalance.
I see no reason to believe that this engine is any different.

Do what you want. On the other thread I posted above, My "rant" explained how changing the pulley to reduce the rotating mass of the engine was almost negligible when compared to all of the other rotating mass.
My guess is that the belt has a greater effect on rotating mass then shedding a pound or two from a piece that is as close to the rotational axis as possible.

How much would notice if you removed two pounds from the crank by drilling right down the middle of it? - NONE
Now if these pulleys are a smaller diameter than stock and you underdrive the AC, Alt, & water pump, then you would definitely feel a difference.

[stugray]

Originally Posted by OICU812

There has now been two official statements by manufacturer themselves saying the LWPs are perfectly fine with our engine So..... Why are some still even trying to discredit?... Seems senseless is all?

I have some magnetic bracelets that I claim will cure all kinds of diseases.
Would you like to buy some? Why not, It cant hurt.

[OICU812]

Originally Posted by stugray

I have some magnetic bracelets that I claim will cure all kinds of diseases.
Would you like to buy some? Why not, It cant hurt.

That has nothing to do with discussion. As said two statements from Subaru themselves those who continue to discount just look more silly by the post just sayin'.....

[stugray]

Originally Posted by OICU812

That has nothing to do with discussion. As said two statements from Subaru themselves those who continue to discount just look more silly by the post just sayin'.....

My point is: Unless the pulley uderdrives the system, it is snakeoil.
Spend your money how you want. Maybe some fuzzy dice will make your car faster.

[OICU812]

Originally Posted by stugray

My point is: Unless the pulley uderdrives the system, it is snakeoil.
Spend your money how you want. Maybe some fuzzy dice will make your car faster.

You're now trying to be an ass to someone who doesent even give a shit ether way pal. Maybe you need to go back re educate yourself to see who has even been making waves here then go slap yourself.

[stugray]

All the Bullshit about phones in microwaves and you are GIVING ME SHIT? Go fuck yourself!
How many of the other poster on this thread have built a racing boxer engine and had it balanced? I am guessing ZERO

[Turdinator]

Originally Posted by stugray

All the Bullshit about phones in microwaves and you are GIVING ME SHIT? Go fuck yourself!
How many of the other poster on this thread have built a racing boxer engine and had it balanced? I am guessing ZERO

Woe, relax dude. No one hear is attacking you personally (that i have read anyway) the phone is just a joke about how intense the debate is over such a small inconsiquential part.

[Apoc]

Originally Posted by stugray

I build 4-cyl Boxer engines for racing. I have the rotating assembly balanced by a pro.
My engine has a "pulley" on the front.
When the machinist balanced the rotating assembly he had to drill holes in the front pulley as well as the flywheel.

If I change the flywheel or the front pulley I have to rebalance.
I see no reason to believe that this engine is any different.

Do what you want. On the other thread I posted above, My "rant" explained how changing the pulley to reduce the rotating mass of the engine was almost negligible when compared to all of the other rotating mass.
My guess is that the belt has a greater effect on rotating mass then shedding a pound or two from a piece that is as close to the rotational axis as possible.

How much would notice if you removed two pounds from the crank by drilling right down the middle of it? - NONE
Now if these pulleys are a smaller diameter than stock and you underdrive the AC, Alt, & water pump, then you would definitely feel a difference.

Found a pic of what I think is the crank shaft and pulley from a type 4 boxer. I can see why it needs to be balanced. This makes the FA20 pulley look like an afterthought lol

[stugray]

Originally Posted by Turdinator

No one hear is attacking you personally

So you dont consider being told" you are an ass, need to reeducate myself and "making waves", to not be a personal attack?
Ok

Originally Posted by Turdinator

the phone is just a joke about how intense the debate is over such a small inconsiquential part.

I know I thought it was funny too. and I agree with "inconsiquential"

[stugray]

Originally Posted by Apoc

Found a pic of what I think is the crank shaft and pulley from a type 4 boxer. I can see why it needs to be balanced. This makes the FA20 pulley look like an afterthought lol

Yep that's a type-IV. That is what I build for a Porsche 914.
Nice lightened flywheel. I assume that engine was running on carbs.

The "Pulley" on those engines is a fan that also doubles as the alternator drive pulley and goes on the top.