Lightened flywheel quick Q

[SBV116]

Two many pies slows you down. Fact. My car is rapid yo. But i am a fat c*nt.

:lolup:

 

[mattjk]

Oh deary me what have I started.

 

[ben_p]

Dont agree nancy boy (BenP)! I will have to take my own lines of investigation I think!!

back in your box see you next week then. after you write a entry on wiki !

 

[172bagss2]

Paul, you need to have sex.

Likely the best offer I will have this weekend and one I shall consider. Thank you. x

 

[mattjk]

I found this thats quite interesting (for anyone that cares about the actual topic lol)

Ever go bowling? Compare an 8 pound bowling ball to a 16 pound bowling ball. The 8 pounder is easier to accelerate (from the stopped position to you throwing the ball at higher speed) and easier to direct (aim). Your arm also gets less tired with the 8 pound ball. The drawback is that the ball loses more speed toward the end of the bowling lane, and may not knock down as many pins as you want. You also have to be more careful with controlling the direction of the ball, since it's easier to fling out the wrong way if your arm twitches or something The 16 pound bowling ball is harder to accelerate and harder to direct, but it carries more speed at the end of the bowling lane because of its higher mass (and resulting higher inertia). It knocks more pins down. It's also harder to send the ball careening into someone else's bowling lane, because it's harder for your arm to suddenly jerk it to the side.

Now relate this analogy to a car... the pins at the end represent your car's weight/mass, the bowling ball is the flywheel, and your arm is the engine. The lighter flywheel will be easier to accelerate and decelerate- so you'll have quicker starts, faster acceleration because the flywheel has less inertia to overcome, and quicker shifts because the revs drop faster when you let off the throttle. The downside is that you have to control the flywheel more, since the direction (speed of rotation) varies that much more. This is why people say that an "8 pound flywheel isn't good for a daily driver". I don't have any problem driving with mine. The heavier flywheel has higher inertia than the lighter one, so it will start your car from a stop more easily (knock down more pins), but it will hurt you everywhere else. It takes more force/power to accelerate (overcoming more inertia), doesn't allow you to shift as quickly (revs don't drop fast enough), but it is easier to drive because the speed of rotation doesn't change as rapidly as the lighter flywheel. Small changes in your throttle position don't change the revs as much, because the power blips are just soaked up in the heavier flywheel. This is why people might think that "a lighter flywheel takes more gas while cruising", because that lighter flywheel takes more attention at the gas pedal than the heavier one to maintain speed. The lighter flywheel will give you better gas mileage.. ever push that 8 pound bowling ball on the ground at a constant speed? Now try the 16 pounder- which one takes more energy to push? The 16 pounder. It's the same as the flywheel.

Do you lose torque with the lighter flywheel? Yes and no. You lose torque to start the car moving, since less energy is stored in the flywheel- so you have to apply more torque from the engine. On the other hand, you use less torque to overcome the inertia of the flywheel while accelerating and decelerating, so you can use the torque from your engine more effectively. You don't lose any torque when going to a lighter flywheel- you just change the source and application of torque in your car's drivetrain.

So...

Light flywheel: better acceleration, better mileage, takes more skill to drive
Heavy flywheel: worse acceleration, lower mileage, takes less skill to drive

 

[mattjk]

Dont agree nancy boy (BenP)! I will have to take my own lines of investigation I think!!

back in your box see you next week then. after you write a entry on wiki !

Its a real shame you dont live closer to me Ben I would teach you to have some respect! (MattJGay style)

 

[Mark One]

swot i said ^

 

[ben_p]

I found this thats quite interesting (for anyone that cares about the actual topic lol)

Ever go bowling? Compare an 8 pound bowling ball to a 16 pound bowling ball. The 8 pounder is easier to accelerate (from the stopped position to you throwing the ball at higher speed) and easier to direct (aim). Your arm also gets less tired with the 8 pound ball. The drawback is that the ball loses more speed toward the end of the bowling lane, and may not knock down as many pins as you want. You also have to be more careful with controlling the direction of the ball, since it's easier to fling out the wrong way if your arm twitches or something The 16 pound bowling ball is harder to accelerate and harder to direct, but it carries more speed at the end of the bowling lane because of its higher mass (and resulting higher inertia). It knocks more pins down. It's also harder to send the ball careening into someone else's bowling lane, because it's harder for your arm to suddenly jerk it to the side.

Now relate this analogy to a car... the pins at the end represent your car's weight/mass, the bowling ball is the flywheel, and your arm is the engine. The lighter flywheel will be easier to accelerate and decelerate- so you'll have quicker starts, faster acceleration because the flywheel has less inertia to overcome, and quicker shifts because the revs drop faster when you let off the throttle. The downside is that you have to control the flywheel more, since the direction (speed of rotation) varies that much more. This is why people say that an "8 pound flywheel isn't good for a daily driver". I don't have any problem driving with mine. The heavier flywheel has higher inertia than the lighter one, so it will start your car from a stop more easily (knock down more pins), but it will hurt you everywhere else. It takes more force/power to accelerate (overcoming more inertia), doesn't allow you to shift as quickly (revs don't drop fast enough), but it is easier to drive because the speed of rotation doesn't change as rapidly as the lighter flywheel. Small changes in your throttle position don't change the revs as much, because the power blips are just soaked up in the heavier flywheel. This is why people might think that "a lighter flywheel takes more gas while cruising", because that lighter flywheel takes more attention at the gas pedal than the heavier one to maintain speed. The lighter flywheel will give you better gas mileage.. ever push that 8 pound bowling ball on the ground at a constant speed? Now try the 16 pounder- which one takes more energy to push? The 16 pounder. It's the same as the flywheel.

Do you lose torque with the lighter flywheel? Yes and no. You lose torque to start the car moving, since less energy is stored in the flywheel- so you have to apply more torque from the engine. On the other hand, you use less torque to overcome the inertia of the flywheel while accelerating and decelerating, so you can use the torque from your engine more effectively. You don't lose any torque when going to a lighter flywheel- you just change the source and application of torque in your car's drivetrain.

So...

Light flywheel: better acceleration, better mileage, takes more skill to drive
Heavy flywheel: worse acceleration, lower mileage, takes less skill to drive

so were in the middle on this? a yank had the final word!

 

[mattjk]

I believe bowling bowls are still measured in Lbs in the UK too Ben! (dumbass )

Well they are at my local anyway!

 

[mini-valver]

Sounds like someone justifying havin a lightened flywheel to me

It does mention rolling inertia there so say you're doing 80mph at 4k, plant your foot, lighter flywheel will react quicker but once you start climbing the revs the heavier one will be more stable and carry more torque IMO.....

 

[mattjk]

It sounds pretty conclusive to me! Basically a larger flywheel will give you more control. Lighter flywheel less inertia less control but I still cant see it reducing top end torque

Ben get your boyfriend to have a quick peek I'm sure he can give a quick yay or nay answer on this.

 

[172bagss2]

Ben get your boyfriend to have a quick peek I'm sure he can give a quick yay or nay answer on this.

Gray knows absolutely c0ck all about this kind of stuff, best leave him out of it...

 

[mini-valver]

I dont think you'd lose torque, but you certainly wont gain any. higher revving engines suffer with a lighter flywheel. FACT.

 

[mattjk]

Mini-Valver - sorry I dont know your name! the question is would I lose any!

172bagss - I didnt mean Gray I meant the other Ben!

 

[172bagss2]

172bagss - I didnt mean Gray I meant the other Ben!

God you've done it now. I don't think Gray knows about Ben. :S

 

[franx]

think the main advantage will be for the skilled sport-track-rally driver who wants the revs to drop solid when changing gears ? A fast reacting engine to the foot/throttle ?

I remember driving a Vauxhall 1.8 last time, when pressing the clutch between changes the engine took forever to drop in rpm, terrible drive ! Maybe a giant weight flywheel in there...

 

[franx]

I dont think you'd lose torque, but you certainly wont gain any. higher revving engines suffer with a lighter flywheel. FACT.

think so too, when for exmple getting wheelspin you will have to be carefull not revving it straight through the redline

 

[MarkCup]

Our Focus 1.6 has a really heavy flywheel, the rev decay or a downshift blip takes forever when changing gear.

I think it's been given it as the 1.6 Zetec isn't particularly torquey. In my opinion the heavier flywheel doesn't affect the torque output of the engine in any way, shape, or form, but it stores 'potential energy' as a rotating mass.

That means that when I get to a steep hill or something, technically the heavy rotating flywheel will help me get up it using the stored potential energy of the rotating mass.

Interesting topic though.

 

[matty w]

i'd imagine it depends on the engines nature,a clio doesnt make power till it revving anyway where as a turbo'd engine it may have an advantage,i'm running a heavier flywheel on my high comp f7R engine