Hard facts about lightened flywheels

[Classic18]

So now my issue is where to get an affordable light flywheel and couple to fit in a SBC/Bravo combo.

suggestions??

[HStream1]

As far as why different light flywheels weigh differently?? That can be attributed to many factors. Were they done by the same person, Same machine with the same program? Diamond, Brendan, Jay Smith, Jeff Dunn all cut them differently therefore there is going to be a weight difference. Even if two wheels were done on the same machine with the same program. After balancing they will be different weights if only by a few Grams.

As far as a 1/2 lb not being ultra critical?? Well Myself as well as others spend alot of time and or money to remove ounces and even a few grams from Pistons and Rods to make sure they are all matched in weight and lighter than stock.

But for River Running purposes IMO its best not to Run a Lightened flywheel. The Up and down Flex due to RPMs will eventually cause stress cracks in the Magnets and possibly the Flywheel itself. Now if its a Billet Flywheel with encased magnets one has a better chance of that not happening.

This is a Stock mercury Lightweight Flywheel At 7.24lbs which is about average weight +- a few grams vs a Flywheel Jeff Dunn and I did for one of my race engines at 4.10 lbs.

I know everyone doesn't have a digital scale. But I would like to see real life numbers. I'm always interested in why does your lightweight flywheel weighs 4.2 lbs and why does another lightweight flywheel for the same motor weigh in at 5.4 lbs. and they are supposedly the same flywheel. I'm betting its because thats what the buyer was told without real evidence. I know 1/2 lb isn't ultra critical, but its just interesting to know why it is what it is. Maybe they are all rough cut pretty close and the other grams are from removing material during balancing. I don't know but I am sure someone knows.

[FMP]

I've heard that

[Mr. Demeanor]

A Lightened Flywheel will give you 200 to 300 more RPMs on the top end.

Explain the physics on that.
Zero difference on mine and other on top end. There are in strong arguments for increased acceleration and better longevity but I have seen none for actual increased max attainable RPM.

[Mr. Demeanor]

🤡.

Gyroscopic effect

[eli]

lighter is always better heavier never won anything, thinking about this when i,m pushing 1200 lbs of morter mix on a cart to the register at menards

[Mr. Demeanor]

lighter is always better heavier never won anything, thinking about this when i,m pushing 1200 lbs of motor mix on a cart to the register at menards

Heavier wins in weight lifting, tractor pulls, sumo wrestling, .....

[HStream1]

Very simply Law of Physics. Accelerating an unnecessary rotating mass requires energy, and the acceleration process saps some of the horsepower we have available to accelerate. Hence Faster Acceleration and Higher RPM's

Explain the physics on that.
Zero difference on mine and other on top end. There are in strong arguments for increased acceleration and better longevity but I have seen none for actual increased max attainable RPM.

[Mr. Demeanor]

Very simply Law of Physics. Accelerating an unnecessary rotating mass requires energy, and the acceleration process saps some of the horsepower we have available to accelerate. Hence Faster Acceleration and Higher RPM's

That doesnt account for an increase in max attainable rpm. Faster acceleration yes. Higher max attainable RPM no.

[Mr. Demeanor]

Take a simple electric motor like a circular saw. Pull the trigger and it attains the same RPM with or without a blade in it. It will attain that RPM sooner without a blade in it.

[HStream1]

Yes it does if the engine is capable of attaining it. If as you say isnt true then based on Physics YOU explain how a motor that is turning say 10000 RPM while under load with weight and rotating mass can spin 12000 when that weight and mass is reduced or eliminated.

That doesnt account for an increase in max attainable rpm. Faster acceleration yes. Higher max attainable RPM no.

[Mr. Demeanor]

Yes it does if the engine is capable of attaining it. If as you say isnt true then based on Physics YOU explain how a motor that is turning say 10000 RPM while under load with weight and rotating mass can spin 12000 when that weight and mass is reduced or eliminated.

I cant explain it because no such a motor exists. The only time weight effects top speed is when it effects frictional drag. We can go round and round. This whole thread has been about exactly what I am saying. No increase in top RPM. Ill let someone else take a stab at explaining it.

[Mr. Demeanor]

We have never expected a lightened flywheel to make more top end horse power in fact it should make less. The #1 point in a lightened flywheel is to stop the top of the crank from coming off at 10,000 RPM. or for that matter at 8000 RPM. But what your test really doesn’t show is the torque gain on acceleration dew to spinning up a lighter mass. In an F1 boat a lightened flywheel is a noticeable gain in acceleration off the turn. On my dyno, as long as the motor is accelerating, the lightened flywheel will make 10 more HP over the stock S3000 type.

Ill just leave the first response to this thread here where someone with real experience answered the question pages ago.

[HStream1]

Im am so glad you posted that. Ill remain silent at this point. ROFLMAO.

I cant explain it because no such a motor exists. The only time weight effects top speed is when it effects frictional drag. We can go round and round. Ill let someone else take a stab at explaining it.

[Mr. Demeanor]

I wish you were right because I would love 200rpm by just lightening a flywheel. Hell I dont really like you and I still hope you are right LOL.