Initially you will not have the full "feel" of the torque off of the line (the torque will be there, but weight is static and does not affect the amount) one thing you will notice is that it will wind up very quickly. It is a give and take situation with flywheel weight, if you are drag racing you will not want a "light as possible" flywheel. For spirited driving lightened and just light flywheels are very nice because you will get your higher revs VERY quickly as there is less mass to spin up.

 

lighting flywheel



Taking weight off the flywheel will allow the engine to rev quicker it will not decrease the torque. Torque is effected by stroke and bore of an engine, increasing the stroke in the Opel CIH engine makes more torque, increasing the bore size makes more torque, but not as much as stroke. If you are going to a larger clutch ie; S-10 or some other replacement then you should lighten the flywheel brecause you are increasing the weight of the rotating assembly with the bigger, heavier clutch. I think you can safeily take 5 or 6 pounds off the stock flywheel without and worry as long as you don't try twisting it 7500-8000 RPM's. I run a 18 pound flywheel with an S-10 clutch assembly on a 2.2 and it does very well.

 

Once an engine is up to speed, the engine speed you usually obtain to pull away from a stop, then as you engage the clutch the tranny,differential and then wheels start to move. These parts, as they are not moving, will resist moving until forced to move. A 15Lb flywheel has more potential energy in it then a 10Lb flywheel. So a 15 Lb flywheel will get the rest of the drive train moving easier then a 10 Lb flywheel. So why isn't a 100Lb flywheel better? Because the engine must get that flywheel moving and it takes more torque to get a 100Lb flywheel moving then a 15Lb one. But once the 100Lb one is moving it is harder to get it stopped. Getting a 100Lb rock rolling down a hill takes some work but it takes more energy to get it to stop.
The bottom line is that is is easier to rev an engine with a lighter flywheel then a heavier one But easier to accelerate from a stop with a heavier one.
I could write a whole book on physics of potential energy, kenetic energy, centrifugal forces and associated formulas to back up this topic but after the couple beers tonight I don't think I can. Look in the search engine as I know this topic has been touched on in a section titled "lightening a flywheel"
Mike

 

I could write a whole book on physics of potential energy, kenetic energy, centrifugal forces and associated formulas to back up this topic but after the couple beers tonight I don't think I can.
Mike

Isn't that backwards, I'm usually MUCH more knowledgeable after a COUPLE of beers. :lmao:
Harold

 

We very recently covered this interesting topic quite thoroughly, I think it was a sidetrack in the thread called "connecting rod FAQ". Maybe those posts should be moved here, so they are all together. What happened was we were discussing the pros (there are no cons) of having lighter yet stronger connecting rods, why lighter reciprocating parts are good for rpms and durability, when we mixed in the effects of having lighter rotating parts. That is a great thread, if you're into the utmost performance available. Check it out!

 

Centrifugal, as in having a tendency to move outward or away from a center. Not centripetal, as in the tendency to move towards the center. When the flywheel is moving at a great speed this is the force that causes it to explode.
Take a 10Lb flywheel. If the majority of its weight is located on the outer rim of it then the centrifugal force is greater then if the majority of its weight is located towards the center. Also, it takes more torque to spin that first flywheel up to speed but it will resist slowing down for longer then the second flywheel. A good example of this is a spinning top. Majority of weight is to the outer part and this is one of the reasons it will spin for a long time. And it resists a change in its travel. This is the basis behind a gyroscope, accelerometers, and many other avionic systems in a jet aircraft.
Alright, enough. I must stop as the smoke from my brain is making it hard to see the screen.
Mike

 

You say Potato, I say Potato

Mike, we are talking about the same thing, but it just depends upon your frame of reference. From Wikipedia:

A real or "reactive" centrifugal force occurs in reaction to a centripetal acceleration acting on a mass. This centrifugal force is equal in magnitude to the centripetal force, directed away from the center of rotation, and is exerted by the rotating object upon the object which imposes the centripetal acceleration.
A pseudo or "fictitious" centrifugal force appears when a rotating reference frame is used for analysis. The (true) frame acceleration is substituted by a (fictitious) centrifugal force that is exerted on all objects, and directed away from the axis of rotation.

They've said it much more eloquently than I could.

jtb

 

Hey, this is fun

And the force is greater as the mass is moving towards the earth and slower as it moves away from the earth because of the gravitational pull of the earth. Of course this is not an issue with the round flywheel. Tho, it might be with the pistons of our engines, albiet to a very minute degree, and not with a horizontally opposed engine like a VW or Boxer motorcycle.:lmao:

Isn't physics fun? Next we could get into fluid dynamics and maybe the inner secrets of velocities in the venturies of the carb and atomization of fuel in relationship to the change in velocities of the air.

Enough. I quit.

Mike

 

... Tho, it might be with the pistons of our engines, albiet to a very minute degree, and not with a horizontally opposed engine like a VW or Boxer motorcycle.:lmao:

Mike

But.. my engine doesn't have pistons, it's a Wankel!!!

OK, I quit too.

jtb

 

What? Quit? This was just getting good.

 

how about slipping the clutch the left foot is a great torque multiplier
the best of both worlds

 

I can testify that the lightened flywheels that we bought in the group buy do "spool up" faster than the stock flywheel. I have one on my Black 2.0 GT that I keep in AZ. There was another group buy last month but perhaps we need another.. I think only 6 are required to make a run. I'm in for 1 just don't know which Opel I'd put it in. Good luck Paul