eBay M20 Light Weight Pulley / Crank Dampner

[KenC]

This thread is hilarious!

[NigelStu]

and to think for my Chump build I was going to put the i flywheel on the e bottom end! what was I thinking???? I almost lost a bunch of torque there!

/sarcasm



O.P. - I'm curious. Did you post this because you were considering what the benefits might be? Or because you saw an aluminum trigger wheel, thought the seller might be on crack and wanted clarification if it would work with the sensors on the M20?

[Jaxx_]

No.


But then again, I'm using the assumption that the air/fuel mixture burning in the cylinder, creating pressure and thus moving the pistons down is what is creating the torque on the crankshaft.

We're not talking about changing anything besides rotating assembly weight. It's harder to stop a box made of lead traveling at 10mph than it is to stop a box made of plastic traveling at 10mph.

If you don't believe it, don't listen to me, keep on thinking that you can run an engine without any weight on the rotating assembly. it's the same concept. I'm not going to bother arguing anymore.

[KenC]

Inertia and torque are different.

[nando]

We're not talking about changing anything besides rotating assembly weight. It's harder to stop a box made of lead traveling at 10mph than it is to stop a box made of plastic traveling at 10mph.

If you don't believe it, don't listen to me, keep on thinking that you can run an engine without any weight on the rotating assembly. it's the same concept. I'm not going to bother arguing anymore.

it's also harder to accelerate, which is what you are doing in an engine, continuously. the rotating parts are *always* accelerating, so more mass does not help it make more torque.

[CorvallisBMW]

Reducing the weight of the rotating assembly will lessen it's INERTIA, allowing the speed of the engine to rise and fall more rapidly. It does not gain you any power. Examples: lightened internals, light flywheel, lightened valvetrain, etc.

TORQUE is a force created by the exploding gases in the cylinders driving the crankshaft to turn. Torque is increased by upping the force exerted on the pistons. Examples: higher c/r, larger displacement, forced induction.

[KenC]

theoretically, it's the same, but the concept could be seen the other way -- less weight means it's easier to slow the rotating assembly. WOT up a steep hill, more weight = more torque. make sense?

F=ma. It's the same final torque, but at a constant acceleration, you have more torque.

You're using that equation incorrectly. Actually I'm not sure how you're interpreting it, as the following sentences make no sense.

With a constant force (force of the engine at any given rpm), a decrease in the mass, will increase acceleration. The equation is different with rotation, but the principle is the same.

[Jaxx_]

Inertia and torque are different.

congrats, guy. you know two different words. Torque = Ia.

it's also harder to accelerate, which is what you are doing in an engine, continuously. the rotating parts are *always* accelerating, so more mass does not help it make more torque.

Yes, hence the reason I said total is the same. I tried to give an example you'd understand, the hill was probably the best I could do. RPMs will drop faster with a lighter motor that's at it's peak output vs a heavier motor that is at it's peak output. This is how torque is going to feel.

[Jaxx_]

You're using that equation incorrectly. Actually I'm not sure how you're interpreting it, as the following sentences make no sense.

With a constant force (force of the engine at any given rpm), a decrease in the mass, will increase acceleration. The equation is different with rotation, but the principle is the same.

yes, that was my mistake with explaining it.

[KenC]

What will my torque curve look like with my new 100lb flywheel?

Oh, I added a 100lb crank dampener too.

[KenC]

RPMs will drop faster with a lighter motor that's at it's peak output vs a heavier motor that is at it's peak output. This is how torque is going to feel.

You're describing inertia.

[Jaxx_]

What will my torque curve look like with my new 100lb flywheel?

Oh, I added a 100lb crank dampener too.

where are we measuring? at the wheels it's going to be less, obviously.

[digger]

Reducing the weight of the rotating assembly will lessen it's INERTIA, allowing the speed of the engine to rise and fall more rapidly. It does not gain you any power. Examples: lightened internals, light flywheel, lightened valvetrain, etc.

TORQUE is a force created by the exploding gases in the cylinders driving the crankshaft to turn. Torque is increased by upping the force exerted on the pistons. Examples: higher c/r, larger displacement, forced induction.

Lightening a flywheel does not give any additional power gains when under load at constant rpm but it does give more power under transient condidtions because less power is required to accelerate the lower inertia flywheel. Having said that the biggest effect is felt under lower gears 1 & 2 where rpms accelerate faster, you can work out how much mass you have equivalently reduces from the vehicle if you know how much mass and where it was taken from.

A lightened flywheel often makes clutch engagement more difficult because the engine has less inertia and can be slowed easier which is why people often wrongly claim it lowers torque. When the clutch is fully engaged there is never less torque.

[KenC]

Give. Up.



OP, don't buy that POS.

[Jaxx_]

You're describing inertia.

I suppose you're right, the core of my argument was more about the feel of torque than torque itself. At the end of the day, I think that that was my point.