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Changing flywheel weight?

czar800

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I had a thread on AS about this and it seemed to draw some interesting points of view. Are there gains to be had in the flywheel? A lot of other motor sports like dirt bikes, drag cars make changes to the flywheel. I wish I could build a flywheel with the same overall weight as stock, but move the weight away from center. How about one that's lighter overall, but with most of its mass away from center. I think there's gains to be had with the flywheel.
 

jacob j.

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When Stihl transitioned the 044 to the MS-440, they made the flywheel lighter. It cost some torque but improved acceleration and gained a few high-end RPM. As with all of these things, there's a trade-off. Adam Clarke built a 372 that didn't even really have a flywheel- he machined a small disc that had a Piezo electric ignition similar to what's used in some R/C machines. He said ultimately it didn't really work as you need some kind of weight there.
 

Terry Syd

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I've played with flywheel weights on dirt bikes. The increase in 'torque' is really just kinetic energy being stored in the flywheel. The stored energy works well when you come up on a vertical cliff or log and need to get over it, it will help to get the engine started and it also helps when you are on loose terrain and need to keep control of the wheel spin. However, once the stored energy is used, you are back to the torque the engine will actually make. Bottom line, once you get the saw stuck in the wood and cutting, a flywheel with more inertia won't make any difference.
 

angelo c

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I had a thread on AS about this and it seemed to draw some interesting points of view. Are there gains to be had in the flywheel? A lot of other motor sports like dirt bikes, drag cars make changes to the flywheel. I wish I could build a flywheel with the same overall weight as stock, but move the weight away from center. How about one that's lighter overall, but with most of its mass away from center. I think there's gains to be had with the flywheel.

I've thought about this in terms of "porting" in a thread the other day. My "opportunity" was if you "build" a saw with high RPM intentions and use a "heavier" flywheel would you have the best of both worlds. Or some combination of "high torque/light flywheel" ect. It seems as a "woods port" is intended to be the best of both worlds....would an "altered weight" flywheel help. ?
 

Gunn

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In theory you could make a huge light weight flywheel with a giant radius and it would generate more torque, but in chainsaws you're constrained to a specified size so there's not a lot of room for gains.
 

jmssaws

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I've got a flywheel for my 064 that's almost machined away and a stock one,the lighter one makes it snappy but in the wood is can't tell a difference between the two.
 

angelo c

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In theory you could make a huge light weight flywheel with a giant radius and it would generate more torque, but in chainsaws you're constrained to a specified size so there's not a lot of room for gains.
You are constrained to a "maximum" size....not so much in minimum size though. And net weight is where the variation exist within the size limitations .

I'm looking for my stopwatch now....I'm betting I can get "30% gains" :cbiggrin:
 

czar800

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I've got a flywheel for my 064 that's almost machined away and a stock one,the lighter one makes it snappy but in the wood is can't tell a difference between the two.

That's surprising about how they both preforme in the wood.
 

David Young

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So let's see some tests
 

czar800

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I really need to build my extra parts base more.... So I could test A few theories.
 

PA Dan

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I can do a test with my hybrid flywheel on my 044. They both started with the same flywheel but I had the hybrid machined.
 

czar800

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Why do I find myself thing about flywheels..... Know my head hurts!!!
 

PA Dan

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My buddy is a machinist and put it on a lathe and put a beveled edge on the back of the flywheel. On the hybrid you have to remove material from the flywheel or the cylinder or both. I opted for the flywheel and then just a little off the transfer area. I'll post a picture later.
d95f7349fd0b10233f3bcd692e74dc66.jpg
9ae3eb50e2477bb2ba627910462c36d1.jpg
0cc4bcadc15cb2a2830d71b7bf706cfa.jpg
This last pic isn't mine it was posted in the hybrid thread on Another Site.
 
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