fidanza flywheels
but a fly wheel does change engine dynamics. If you go too light on the flywheel then the idle quality will suffer. The engine uses the flywheel's momentum to help smooth out the idle of the engine. Go too light, and the smoothness of the idle will go to crap.
The stock flywheel also helps to make starting the car from a dead stop easier as well, because it has the mass to keep spinning the engine. Like wise, a lighter flywheel will require you to "give it more gas" to get the car moving, because it is has less mass to keep the engine spinning.
But I agree with your main point, a lighter flywheel won't actually affect the horse power the engine is making. It just allows the engine to 'spool up' faster. Given this information, and knowing that dynos are essentially treadmills for cars, a car that spins the tread mill up faster will be interpreted as having more power/torque, even if there really isn't a change in actual power. So, in regards to dynos vs. flywheels, the dyno readings can be a bit miss-leading.
The end result (for a street car) will be that there's almost no deference in the car's acceleration. You're still moving a 3000+ lbs car from a dead stop, but a lighter flywheel will make it more difficult to do.
The stock flywheel also helps to make starting the car from a dead stop easier as well, because it has the mass to keep spinning the engine. Like wise, a lighter flywheel will require you to "give it more gas" to get the car moving, because it is has less mass to keep the engine spinning.
But I agree with your main point, a lighter flywheel won't actually affect the horse power the engine is making. It just allows the engine to 'spool up' faster. Given this information, and knowing that dynos are essentially treadmills for cars, a car that spins the tread mill up faster will be interpreted as having more power/torque, even if there really isn't a change in actual power. So, in regards to dynos vs. flywheels, the dyno readings can be a bit miss-leading.
The end result (for a street car) will be that there's almost no deference in the car's acceleration. You're still moving a 3000+ lbs car from a dead stop, but a lighter flywheel will make it more difficult to do.
Here's the Engineer's opinion: (And I'm working through this for my benefit too)
Lighter parts can increase efficiency, assuming efficiency is measured by mpg, not crank hp. For example, shaving 100 lbs off the car will reduce the friction loss of the tires on the road, and thus more miles per gallon will occur.
It's all based on Newton's Laws:
A lighter flywheel will require less energy to go from a lower rpm (ie 0) to a higher rpm when compared to a heavier flywheel. Less energy used in increasing the angular rotation of the flywheel will allow for quicker acceleration, assuming the driver uses the same amount of gas.
At a constant rpm, the fuel consumption will not be affected, as the only forces on the car is friction at the tires and wind resistance. (the reduction in vehicle weight with the lighter flywheel only has a marginal effect on friction) However, a lighter flywheel will have much less of a buffer effect on velocity during driving. This means the car will have a tendancy to slow down faster when you take your foot off the pedal.
Now this is where the higher gas mileage that some people may experience could come from: When a car slows and speeds up faster, people adjust speed using the gas pedal. But people have a tendancy to react late, and overreact to speed fluctuations. Reacting late and overreacting are detrimental to good gas mileage.
A lighter flywheel could have greater frequency of speed fluctuations, and hence it would be possible for gas mileage to suffer slightly. Use of cruise control would eliminate the human error, and better gas mileage performance may occur.
Lighter parts can increase efficiency, assuming efficiency is measured by mpg, not crank hp. For example, shaving 100 lbs off the car will reduce the friction loss of the tires on the road, and thus more miles per gallon will occur.
It's all based on Newton's Laws:
A lighter flywheel will require less energy to go from a lower rpm (ie 0) to a higher rpm when compared to a heavier flywheel. Less energy used in increasing the angular rotation of the flywheel will allow for quicker acceleration, assuming the driver uses the same amount of gas.
At a constant rpm, the fuel consumption will not be affected, as the only forces on the car is friction at the tires and wind resistance. (the reduction in vehicle weight with the lighter flywheel only has a marginal effect on friction) However, a lighter flywheel will have much less of a buffer effect on velocity during driving. This means the car will have a tendancy to slow down faster when you take your foot off the pedal.
Now this is where the higher gas mileage that some people may experience could come from: When a car slows and speeds up faster, people adjust speed using the gas pedal. But people have a tendancy to react late, and overreact to speed fluctuations. Reacting late and overreacting are detrimental to good gas mileage.
A lighter flywheel could have greater frequency of speed fluctuations, and hence it would be possible for gas mileage to suffer slightly. Use of cruise control would eliminate the human error, and better gas mileage performance may occur.
Here's the Engineer's opinion: (And I'm working through this for my benefit too)
Lighter parts can increase efficiency, assuming efficiency is measured by mpg, not crank hp. For example, shaving 100 lbs off the car will reduce the friction loss of the tires on the road, and thus more miles per gallon will occur.
It's all based on Newton's Laws:
A lighter flywheel will require less energy to go from a lower rpm (ie 0) to a higher rpm when compared to a heavier flywheel. Less energy used in increasing the angular rotation of the flywheel will allow for quicker acceleration, assuming the driver uses the same amount of gas.
At a constant rpm, the fuel consumption will not be affected, as the only forces on the car is friction at the tires and wind resistance. (the reduction in vehicle weight with the lighter flywheel only has a marginal effect on friction) However, a lighter flywheel will have much less of a buffer effect on velocity during driving. This means the car will have a tendancy to slow down faster when you take your foot off the pedal.
Now this is where the higher gas mileage that some people may experience could come from: When a car slows and speeds up faster, people adjust speed using the gas pedal. But people have a tendancy to react late, and overreact to speed fluctuations. Reacting late and overreacting are detrimental to good gas mileage.
A lighter flywheel could have greater frequency of speed fluctuations, and hence it would be possible for gas mileage to suffer slightly. Use of cruise control would eliminate the human error, and better gas mileage performance may occur.
Lighter parts can increase efficiency, assuming efficiency is measured by mpg, not crank hp. For example, shaving 100 lbs off the car will reduce the friction loss of the tires on the road, and thus more miles per gallon will occur.
It's all based on Newton's Laws:
A lighter flywheel will require less energy to go from a lower rpm (ie 0) to a higher rpm when compared to a heavier flywheel. Less energy used in increasing the angular rotation of the flywheel will allow for quicker acceleration, assuming the driver uses the same amount of gas.
At a constant rpm, the fuel consumption will not be affected, as the only forces on the car is friction at the tires and wind resistance. (the reduction in vehicle weight with the lighter flywheel only has a marginal effect on friction) However, a lighter flywheel will have much less of a buffer effect on velocity during driving. This means the car will have a tendancy to slow down faster when you take your foot off the pedal.
Now this is where the higher gas mileage that some people may experience could come from: When a car slows and speeds up faster, people adjust speed using the gas pedal. But people have a tendancy to react late, and overreact to speed fluctuations. Reacting late and overreacting are detrimental to good gas mileage.
A lighter flywheel could have greater frequency of speed fluctuations, and hence it would be possible for gas mileage to suffer slightly. Use of cruise control would eliminate the human error, and better gas mileage performance may occur.
If you measure efficiency through MPG, a lighter flywheel reduces efficiency. The problem is interia, a lighter flywheel will lose and gain speed at a faster rate than a heavier flywheel. This makes modulating the speed harder and the changes more abrupt.
but a fly wheel does change engine dynamics. If you go too light on the flywheel then the idle quality will suffer. The engine uses the flywheel's momentum to help smooth out the idle of the engine. Go too light, and the smoothness of the idle will go to crap.
The stock flywheel also helps to make starting the car from a dead stop easier as well, because it has the mass to keep spinning the engine. Like wise, a lighter flywheel will require you to "give it more gas" to get the car moving, because it is has less mass to keep the engine spinning.
But I agree with your main point, a lighter flywheel won't actually affect the horse power the engine is making. It just allows the engine to 'spool up' faster. Given this information, and knowing that dynos are essentially treadmills for cars, a car that spins the tread mill up faster will be interpreted as having more power/torque, even if there really isn't a change in actual power. So, in regards to dynos vs. flywheels, the dyno readings can be a bit miss-leading.
The end result (for a street car) will be that there's almost no deference in the car's acceleration. You're still moving a 3000+ lbs car from a dead stop, but a lighter flywheel will make it more difficult to do.
The stock flywheel also helps to make starting the car from a dead stop easier as well, because it has the mass to keep spinning the engine. Like wise, a lighter flywheel will require you to "give it more gas" to get the car moving, because it is has less mass to keep the engine spinning.
But I agree with your main point, a lighter flywheel won't actually affect the horse power the engine is making. It just allows the engine to 'spool up' faster. Given this information, and knowing that dynos are essentially treadmills for cars, a car that spins the tread mill up faster will be interpreted as having more power/torque, even if there really isn't a change in actual power. So, in regards to dynos vs. flywheels, the dyno readings can be a bit miss-leading.
The end result (for a street car) will be that there's almost no deference in the car's acceleration. You're still moving a 3000+ lbs car from a dead stop, but a lighter flywheel will make it more difficult to do.
Read the reviews from the last generation, it's not like on one cars it's going to do nothing while on another it's going to make it a rocket. Reviews also only tell you so much, you can find reviews that tell you an intake makes the car substantially faster but we know that's wrong.
Evolving Member
Joined: Sep 2007
Posts: 344
Likes: 0
From: So Cal
i think by now i would know whats exxagerated and what's not. Reviews help. They're not the end-all, but that's some form of a starting point for me when i buy anything. sports gear, car crap, video games, music. it all helps.
How would you though unless you have personal experience with the product at hand? I honestly thought a lancer could be made fast NA (look at some of my older posts) and I didn't change that view until I tried and failed myself.
After getting a lot more wheel time in my GTS, I'd have to guess that our cars have a pretty dang heavy fly-wheel. I'm assuming this based on how long it takes the engine to return to idle speed after rev'ing it up pretty high, and how well the 'engine braking' works.
My previous car was had a 1.8L 4 with 4speed MT. A rev to 4k RPM would return to idle MUCH more quickly (probably half the time or less) than it takes my GTS. Engine braking in my old car began as soon as I lifted my foot off the throttle, there's a good 2 or 3 second delay in the GTS before I feel the effects of engine braking.
A lightened flywheel will certainly improve engine responsiveness (both in pick up and slow down). Anyone have data on the stock flywheel and the lightened version(s) out there?
My previous car was had a 1.8L 4 with 4speed MT. A rev to 4k RPM would return to idle MUCH more quickly (probably half the time or less) than it takes my GTS. Engine braking in my old car began as soon as I lifted my foot off the throttle, there's a good 2 or 3 second delay in the GTS before I feel the effects of engine braking.
A lightened flywheel will certainly improve engine responsiveness (both in pick up and slow down). Anyone have data on the stock flywheel and the lightened version(s) out there?
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