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Anyone Dyno there car with fidanza Flywheel yet?

3.4K views 28 replies 17 participants last post by  Mazda Gremlyn  
#1 ·
Just wanted to know the HP/TQ numbers are worth the purchase of this lighter flywheel.
 
#3 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

A lighter flywheel will not produce any more HP or torque. All that it does is
allow the engine to rev quicker, essentially producing better throttle response.

As these cars have the drive by wire system, this pretty much eliminates
the posiblity of good throttle response, no matter how light the
flywheel or rotating mass is.:(
 
#4 ·
Reading Topic: Anyone Dyno there car with fidanza Flywheel yet?

badgerman,

the comment that a lighter flywheel will not produce any more power is not correct.

It has been proven in the past that a lighter flywheel allows more of the engines power/torque to make it to the wheels. Instead of the engine having to spin, say, a 15lb flywheel, now it only has to spin up a 9lb mass. The amount of energy the engine no longer has to use to spin up the extra weight makes its way to the wheels.

The lighter you can make the entire driveline, the better, even so far as lightweight forged racing rims, etc.

Nikolas
 
#5 ·
Reading Topic: Anyone Dyno there car with fidanza Flywheel yet?

A lightened flywheel, along with lightened anything will help.

Lightened flywheels typicall free up a few hp...probably in the range of 5-10, plus it will allow the engine to rev easier.

Basically the rotating mass in the driveline is one part of the driveline power loss...Decrease the weight and you'll free up a few hp.
 
#6 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Draxas, I hate to disagree with you, but in this case,
I do not believe that your statement is entirely accurate.

A flywheel is considered a energy storage device, much like a battery.
As a battery stored energy in electrical form, a flywheel stored energy
in the form of kinetic energy.

So, as it requires more energy to charge a large battery, it requires
more energy (in the form of power) from the engine to spin up a
large flywheel. However, when the flywheel is spinning, it is storing
that power from the engine. So, when you let off the gas, you have
good deal of energy stored in the flywheel, this gets transfered to
the driveline.

At a constant RPM, a 1 Kg flywheel is the same as a 1000 Kg flywheel, it
just takes more energy to spin up the 1000 Kg flywheel, but consequently,
once it is spinning, it is storing all of that energy, and this energy is availible
for use.

In a driveline, all energy that is lost is due to friction. Friction converts
mechanical energy (from the engine) into heat energy, and this is dissapated
into the surrounding air. Yes, with a heavier driveline, more energy is required
to spin it up (storing kinetic energy in it), but that energy is not lost, it is stored
in the driveline.
 
#7 ·
Reading Topic: Anyone Dyno there car with fidanza Flywheel yet?

badgerman, from taking EXACTLY what you said...

if it takes more energy to spin, if you lighten the flywheel, that now unused energy is transfered to the wheels.

also, what has the best advantages? When you let off the gas, and the "stored" energy is being used or have the ability to accelerate faster?
 
#8 ·
Reading Topic: Anyone Dyno there car with fidanza Flywheel yet?

But isn't the whole point of a lighter flywheel to increase the horsepower transfered at the wheels while accelerating? I mean, when you're not pressing the gas, it doesn't matter if you have a 1000kg or 1kg flywheel at that point, and if it does, wouldn't a lighter one spin faster anyway? How about the force when it's spinning? Does a heavier flywheel transfer more force (or power or whatever) to the wheels than a lighter one?
 
#9 ·
Reading Topic: Anyone Dyno there car with fidanza Flywheel yet?

Crimson773, I will field that question, with a question and a scenario of my own.

Take two cars, both cars are the same year, make, model, engine, everything, everything is dead the same on both cars except for one thing. The wheels and tires.

On car A, you have nice lightweight wheels, lightweight tires, wheels weigh about 13 lbs each, tires about 21 lbs each. Now car B went for the Bling factor, his car has 40 lbs each chrome wheels and the tires weigh a solid 32 lbs each. If both cars both have the same reaction time on the track, which one would A) Get a quicker start and finish first and B) Who would stop first?
 
#10 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Yes, the car with lighter wheels will stop and start quicker, (not to mention handle better, and have a smoother ride because of a better ratio of unspring vs sprung weight).

But, each tire / wheel will weigh, say 35 lbs, plus wheight of brakes, say 15 lbs per corner,
plus axles, about 10 lbs a peice, plus gearbox, say 25lbs of rotating mass, plus clutch / presure plate, say 10 lbs, plus the crank / rods / cams / etc, about 20 lbs. The total comes to 275 lbs.

going from a 10lb flywheel to a 5lb flywheel come out to a 1% change in rotating mass. No granted, none of the earliner items have the same radius or RPM, therefore, none of them will count equally twords the total rotational inertial of the driveline, so loosing 5 lbs of the flyweel may acount possibly for 5%, but even this is still (in my opinion) negligble.

Here is this for an experiment, leave your car in neutral, and rev up the engine, revs up pretty quick yes? Now, imagine your car in gear, accelerating, will the rate of change of the engine RPM in gear ever come close the rate of change of engine RPM in neutral?

In my opinion, If you are driving a F1 car, a light a possible flywheel is a good idea, but a Mazda 6 is not in the same leage as a F1 car. Again, in my opinion, a lightened flywheel is a waste of money for the Mazda 6. Personally, I would spend my money on intake / exhaust. Far and away, the most bang for the buck will be the diablosport tuner, which will come out hopefully soon, as I am very eagerly waiting to spend my money on one of these.
 
#11 ·
Reading Topic: Anyone Dyno there car with fidanza Flywheel yet?

But, each tire / wheel will weigh, say 35 lbs, plus wheight of brakes, say 15 lbs per corner,  
plus axles, about 10 lbs a peice, plus gearbox, say 25lbs of rotating mass, plus clutch / presure plate, say 10 lbs, plus the crank / rods / cams / etc, about 20 lbs. The total comes to 275 lbs.  

going from a 10lb flywheel to a 5lb flywheel come out to a 1% change in rotating mass. No granted, none of the earliner items have the same radius or RPM, therefore, none of them will count equally twords the total rotational inertial of the driveline, so loosing 5 lbs of the flyweel may acount possibly for 5%, but even this is still (in my opinion) negligble.
Negligible to you may not be negligible to someone else...

In your example you equate flywheel weight as having X% impact on the total drivetrain loss. But, as you said, the same formula applies for the wheels, and a similar decrease of 5 lbs of wheel weight (let's say 2.5 per drive wheel) can make a huge difference in 1/4 times.

If people will pay an extra $1,000 to $2,000 or more for lightweight Volks or SSRs to lose a few lbs of rotational mass and inertia, I think they'll spend a few hundred for a lighter weight flywheel; the least benefit of which is the HP/TQ on the ground gains.

Bottom line is that flywheels are most definitely not the best "bang for the buck", but they do acheive gains.

For anyone trying to get the most out of a N/A Mazda6, a lightweight flywheel is a must. Maybe not the first place your money should go. But it'll probably be in there at some point. For a lot of people, every bit of whp you can squeeze out counts.
 
#12 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Originally posted by badgerman
none of the earliner items have the same radius or RPM, therefore, none of them will count equally twords the total rotational inertial of the driveline,

So lightweight tires and wheels will only prevail against heavier wheels and tires if their radius and revs/mi is different?

I said EVERYTHING was the same between the two except for the WEIGHT difference, the radius and revs/mi all remained the same.

A less theoretical example, a 205/60R16 has a radius of 12.8" and revs/mi of 785, yet a 245/50R16 has a radius of 12.8" and a revs/mi of 786.
 
#13 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Of course lighter tires / wheel will help, and in more ways than just acceleration.

What is was trying to say was that you can not count a wheel the same as you can count an axle. The calculation for rotational inertia is based on where the weight is distibuted relative towords the center of rotation. Because a tire / wheel has a much larger radius than an axle, even if the tire / wheel weighed the same as an axle, the tire / wheel would have a much higher rotational intertia.

To calculate rotational inertia, you need to know a lot of things, such as radius, RPM, and most importantly weight distubution. (is the weight distubuted at the center or the outside) I do not know the values of all of these for every single rotating item, I was just trying to come up with a rough guess, and error on the light side (hence my estimate of 5% instead of 1%), and see what proprotion to the total rotating mass a flywheel contributes.

So, my guess is that a flywheel contributes less than wheels / tires.
 
#14 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Originally posted by badgerman
To calculate rotational inertia, you need to know a lot of things, such as radius, RPM, and most importantly weight distubution. (is the weight distubuted at the center or the outside) I do not know the values of all of these for every single rotating item, I was just trying to come up with a rough guess, and error on the light side (hence my estimate of 5% instead of 1%), and see what proprotion to the total rotating mass a flywheel contributes.
I = aMR^2, thats all you need to calculate rotational inertia, where the 'a' depends on the shape of the object (for a disc, I believe a = 0.5). Reduce the mass of a similar sized object, you reduce the rotational interia, its that simple.

As for the whole energy storage thing, thats not entirely true. It would be true if once you started the wheel spinning, it kept spinning with the same speed and no external force applied, but we can't do that unfortunately. The flywheel requires a constant force applied to it to keep spinning at constant speed, and where there is a force, there is work done, and where there is work done, we have power. So is less force is required to spin the flywheel at a constant rate, less work is done and less power is needed, freeing up more power to make it to the wheels.
 
#15 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Originally posted by Mazda_Gremlyn

I = aMR^2, thats all you need to calculate rotational inertia, where the 'a' depends on the shape of the object (for a disc, I believe a = 0.5). ...
Haha we just covered this in physics class, you are correct it is I = (.5)MR^2

It all about increasing the power to the wheels.
 
#17 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Badgerman, you are wrong about a flywheel storing kinetic energy. you have your definitions mixed up. kinetic energy is energy being used or energy in use. in your case when you said the flywheel is storing kinetic energy, thats implying the energy is not being used at the time, thus it is called POTENTIAL energy. in my opinion a lighter flywheel is going to free up the standing and rotating mass of a heavier flywheel. think of it as a third class lever. like when you close a huge door by pushing on the inside near the piano hinges. the foce moves less distance but takes more effort. if the door is a screen door, when you push it closed it takes less effort. now apply that to a flywheel. the crankshaft is turning the inside of the flywheel with the outside as the rotating mass. get a lighter flywheel and you have less rotating mass.
 
#18 ·
Replying to Topic 'Anyone Dyno there car with

OK, I did some calculations, and might be possible to gain a few wheel HP, but I would like to see some 1/4 times before and after the flywheel change.

Here is some calculations of potential power gain:

1 hp = 746 watts

for a disk, I will approximate a flywheel as a solid disk,
rotational intertia (I) = 1/2 * M * r^2 where
M = mass and r = radius

kinetic energy, (K) = 1/2 * I * w^2 where w = angular velocity in rad / s

and to convert RPM to rads / second: RPM = pi /30 rads / second

So, the numbers I found (from a contour, could not find weight of a stock 6s flywheel) are:

stock flywheel: m = 9.97 kg, radius = .15m
fidanza flywheel: m = 4.5 kg, radius = .15m

So, what I did is calculate energy of the flywheel at idle (1000 rpm), and at 6000 rpm, and I time my 1st gear acceleration, from idle to redline (40 mph), got about 3 seconds.

So, stock flywheel:
idle energy: (.5)(.5)(9.97 kg)(.15m)^2(1000 * pi / 30)^2 = 614 Joules
redline energy: (.5)(.5)(9.97 kg)(.15m) ^2(6000 * pi / 30)^2 = 22117 Joules
HP to accelerate from idle to 6000 rpm : (22117 - 614) / 3 seconds = 9.6 HP

And for fidanza flywheel:
idle energy: (.5)(.5)(4.5 kg)(.15m)^2(1000 * pi / 30)^2 = 277 Joules
redline energy: (.5)(.5)(4.5 kg)(.15)^2(6000 * pi / 30)^2 = 9982 Joules
HP to accelerate from idle to 6000 rpm: (9982 - 277) / 3 seconds = 4.33 HP

So, under load 1st gear acceleration, you could theoretically gain 5.3 HP

To keep the flywheel, or any other mass rotating at a constant velocity, neglecting air resitance requires no power, power is only required to accelerate or decelerate the rotating mass.

Also, consider that the flywheel is there for a reason, it is part of the engine balancing, and is designed to smooth out power delivery.

So, 5.3 HP is just theoretical only on acceleration. It is unlikly that you will not see any change in dyno numbers, but you may see a small change in 1/4 mile times. Again, I would really like to see some 1/4 mile times before shelling out $400, and yanking my transmission.
 
#20 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Originally posted by badgerman
and to convert RPM to rads / second: RPM = pi /30 rads / second
Not sure what you wrote here, but 1 RPM (rev/min) converts to 60 rev/s, and to convert rev/s to rad/s you multiply by, I believe, 2pi, giving you 120pi rad/s for each RPM, that may change the numbers a bit, if you want to rework, but you get the point, less hp is used up turning the flywheel, so you get those few extra ponies to your wheels.

Also, its pretty common for companies to put the majority of the mass close in around the axis of rotation, so that will yield even greater difference in I.



To keep the flywheel, or any other mass rotating at a constant velocity, neglecting air resitance requires no power, power is only required to accelerate or decelerate the rotating mass.  
In a perfect world this would be true, but you're negelecting friction, gravity, etc. Plus you're only analyzing the flywheel itself, and forgetting it has to turn a whole bunch of other stuff that will also cause it to slow down if a force is not applied to it.
 
#21 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Not sure what you wrote here, but 1 RPM (rev/min) converts to 60 rev/s, and to convert rev/s to rad/s you multiply by, I believe, 2pi, giving you 120pi rad/s for each RPM,
No problem, this should make more sense:

1 RPM = 1 rev / min
1 rev / min = (2 * pi) rad / min because 1 complete revolution = 2pi rad

to convert so seconds, you multiply the whole thing by (1m / 60s) note, this equals one, so you are just multiplying it by one, all this does is change the dimensional units:

((2 * pi) rad / s) * (1m / 60s) = ((2 * pi)/60) rad / second

and simplifying we get:
1 rev / min = (pi / 30) rads / second

I dug out my old physics book, and got this conversion from it.

When you thing about it, 5.3 HP sounds about right for the amount of power to spin up a 5kg disk to 6000 rpm in 3 seconds. At first I also thought it was 120 pi rads / s but using this conversion, I came up with thousands of HP needed, and this is just wrong.
 
#24 ·
Reading Topic: Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

Wouldn't you lose revs quickly too? I would think that a lightened flywheel would be annoying on the highway,m
Why?

When I left off the gas, I want the car to slow down. Not sit and think about it for a minute then decide it's going to do it very slowly.
 
#25 ·
Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

And everytime you upshift, you want the revs to drop to match anyway.

All this talk about inertia and stuff is makin me dizzy. All I know is that its been dyno proven to "unlock" more power in the engine. The lighter you make everything respectively, the better off you'll be. And if you are doing a clutch swap, what better time to swap out the flywheel? Might as well. But as some have mentioned, this isn't the type of mod you'd do exclusively.
 
#26 ·
Reading Topic: Replying to Topic 'Anyone Dyno there car with fidanza Flywheel yet?'

If i were going to add a flywheel, it would be at the same time as a clutch AND LSD. Might as well save on the labour.