1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

lightweight flywheel...doesn't make sense

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Old Mar 3, 2005 | 08:39 AM
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lightweight flywheel...doesn't make sense

I just bought a lightweight steel flywheel from Racing Beat and counter weight. With their combined wieight, doesn't it add up to the stock flywheel????? Did I just blow $400 out my @$$?
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Old Mar 3, 2005 | 10:12 AM
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i believe they already include the weight of the counterweight in their total. I took my 85 aluminum flywheel and counterweight to work and put it on the scale came out to 4 lbs for the c/w and 8 lbs for the f/w. web site says it ways 12 lbs.
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Old Mar 3, 2005 | 10:29 AM
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Regardless, the mass of the counterweight is further inboard than the mass of the stock flywheel, so even if they weighed the same, the light flywheel/counterweight combo wins.
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Old Mar 3, 2005 | 11:30 AM
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Why a light flywheel? All it does is allow the engine to accelerate faster, and the engine is already capable of accelerating far faster when unloaded than it can when the rubber is on the road. Lighter flywheel hurts drag race capability by making it easier for the engine to bog when the clutch is engaged. Maybe it helps a little between shifts since engine speed can change faster, but clutch slippage seems to make that up anyway. Flywheel weight has nothing to do with topspeed.

B
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Old Mar 3, 2005 | 11:35 AM
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Originally Posted by bliffle
Why a light flywheel? All it does is allow the engine to accelerate faster, and the engine is already capable of accelerating far faster when unloaded than it can when the rubber is on the road. Lighter flywheel hurts drag race capability by making it easier for the engine to bog when the clutch is engaged. Maybe it helps a little between shifts since engine speed can change faster, but clutch slippage seems to make that up anyway. Flywheel weight has nothing to do with topspeed.

B
lighter flywheels means lighter drivetrains, lighter drivetrain means more hp at the wheels. flywheels are important too...
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Old Mar 3, 2005 | 11:36 AM
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^ who said anything about top speed?
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Old Mar 3, 2005 | 11:38 AM
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^ who said anything about top speed? and what makes you think he wants to drag race?
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Old Mar 3, 2005 | 12:04 PM
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Originally Posted by Elysian
lighter flywheels means lighter drivetrains, lighter drivetrain means more hp at the wheels. flywheels are important too



Originally Posted by bliffle
Flywheel weight has nothing to do with topspeed.
B
I think it does.

READ HERE: http://mazdatrix.com/f-writng.htm

For example if you have 2 identical cars, going uphill, with the only differencee being the lighter flywheel, and you top of 5th I think that the one with the lifhter flywheel will have a higher top speed.

AS:
Originally Posted by Elysian
lighter flywheels means lighter drivetrains, lighter drivetrain means more hp at the wheels. flywheels are important too
Less effort to push the car foward.

Even thou the diffference would not be great, but still make a difference.


My opinion.

-Ryan
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Old Mar 3, 2005 | 12:09 PM
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i went from stock flywheel in my 87 TII(and ultimately in the 88TII i got after it) which i think was 24 lb's, to a 12 lb aluminum(7+5 for counterweight), and the difference was very very noticeable... while it did have to rev a little bit higher to start from a stop, it definately had more power... the butt dyno said yes haha
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Old Mar 3, 2005 | 01:27 PM
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A lighter flywheel will increase low gear acceleration, but won't effect top end speed, nor will it help you climb hills faster. Especially by the time you got to 5th, since the difference would be negligable.
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Old Mar 3, 2005 | 01:31 PM
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ALL a lighter flywheel will do is make an engine (any engine) react faster to changes in the throttle position. It will accelerate easier, and will decelerate easier. It'll hardly win any hp. Of course all the wheight your car can loose will influence the power/wheight ratio, but don't expect you'll ever notice the difference of the flywheel wheight as such. What you'll notice is a more "nervous", better reacting engine. A lighter flywheel won't really add top-speed. But since stock flywheels on rotary engines are all oversized, it's not a bad thing to get a lighter one. A flywheel is mainly there as a balancer to smooth out vibrations typical of piston engines. We obviously don't need such a heavy balancer.
As for going uphill, a lighter flywheel will actually make you slower! The flywheel mass "stores" the energy, making sudden changes in load less noticable, while with a lighter flywheel, you might have to shift back sooner.
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Old Mar 3, 2005 | 01:52 PM
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Originally Posted by rotary emotions
ALL a lighter flywheel will do is make an engine (any engine) react faster to changes in the throttle position. It will accelerate easier, and will decelerate easier. It'll hardly win any hp. Of course all the wheight your car can loose will influence the power/wheight ratio, but don't expect you'll ever notice the difference of the flywheel wheight as such. What you'll notice is a more "nervous", better reacting engine. A lighter flywheel won't really add top-speed. But since stock flywheels on rotary engines are all oversized, it's not a bad thing to get a lighter one. A flywheel is mainly there as a balancer to smooth out vibrations typical of piston engines. We obviously don't need such a heavy balancer.
As for going uphill, a lighter flywheel will actually make you slower! The flywheel mass "stores" the energy, making sudden changes in load less noticable, while with a lighter flywheel, you might have to shift back sooner.
have you ever had a lightweight flywheel? or are you basing this on hearsay? i've had one, and seen the benefits.
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Old Mar 3, 2005 | 02:10 PM
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If you have had one then you should know that the only way to affect top end is through gears. If you are geared to top out at 100 let's, a lighter flywheel is not going to make you go 110. The man is right in his statement about not adding any hp. Response is what you gain. Same as if yo do a direct fire conversion you get better and faster response.
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Old Mar 3, 2005 | 02:55 PM
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It does add HP, Usable HP. It will not make the engine produce anymore HP, but it will let you use more of that. I forget what percentage of actual power gets to the wheels through the drivetrain. but using a Lightened flywheel will lower the percentage of power being robbed by your drivetrain. same thing as lightened rims, but more of an impact.
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Old Mar 3, 2005 | 03:05 PM
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I would imagine that a lighter flywheel would allow the engine to spend less energy on turning the fly wheel, would it not? I've always been under the impression that lighter flywheel = more power (more power that's available, not actual more power.) Less energy would be spent on turning the flywheel and more of it could be spent turning the tires.

I dunno, I'm not very technically-inclined when it comes to this stuff.

[edit]KINETIC ENERGY = 1/2 (MASS) (VELOCITY)^2

You want more kinetic energy in an engine, correct? Less mass = less kinetic energy spent turning the wheels.
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Old Mar 3, 2005 | 03:23 PM
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More power to the wheels is not the same thing as adding more hp. What you get in that statment is the same thing that I said. Faster respnose. Which is the same thing Rotary emotions was saying to begin with. Now that we are all in agreement.......
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Old Mar 3, 2005 | 03:31 PM
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bump
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Old Mar 3, 2005 | 05:05 PM
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Originally Posted by Brianhsval
More power to the wheels is not the same thing as adding more hp. What you get in that statment is the same thing that I said. Faster respnose. Which is the same thing Rotary emotions was saying to begin with. Now that we are all in agreement.......
thats all i've ever been saying... but if you think about it, more power to the wheels, would mean slightly higher top speed. unless u got a motor built enough that it would rap out 5th gear no sweat, thats a different story, if ur talkign top speed governed by rev limit, not by actual power...
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Old Mar 3, 2005 | 08:55 PM
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I was confused by the "Faster Response" thing. I figured you were talking about more power to the wheels, but I wasn't positive.

When I hear "faster response", I think quicker free-revving (which I suppose would be the same thing if it were in gear.)
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Old Mar 3, 2005 | 11:03 PM
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A light flywheel doesn't affect power or top speed and any way. The advantage of the lighter flywheel is increased acceleration (and increased deceleration) due to having less rotating inertia. It is a similar affect as lightening the fame of the car. Since:

Force = Mass x Acceleration (Newton's Second Law)

A reduction in mass (rotational or otherwise) means that you can get more acceleration for a given force (related to torque to the wheels). The flywheel doesn't change the power of the engine or driveline losses, so power and torque to the wheels remain unaffected.

The top speed of the car is just a balance between power and drag/driveline friction (assuming not rpm limited). This means that the same car with a heavy or light flywheel has the same top speed (the heavy flywheel just take a longer time to reach it).

Basically, for lightweight flywheels
+ increased acceleration (and freer reving)
- increased deceleration (speed drops faster going up hill, letting off the gas, etc.)
- idle not quite as smooth (heavy flywheels smooth out idle)
- may need to rev a bit higher before disengaging clutch

It is just a matter of what you are looking for in you car. There are advantages and disadvantages of either one.

Kent
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Old Mar 3, 2005 | 11:17 PM
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Ok, like I said, all of this comes down to faster response. Quicker acceleration = ???? faser response. Increased acceleration, due to whatever still = faster response. More power to the wheels = faster response. What am I missing here? Everyone to me is saying the same thing just wording it different. Do the math however you like, but it all comes down to sitting your butt behind the wheel and the car reacting faster, quicker it is all the same. Unless you do some porting your not adding hp. Maybe some track times whould say it better. No light flywheel = oh, for the sake of it a 2.2 60' and a light flywheel = a 1.9.

I'm not trying to be a smart *** or nothing either just trying to get this in perspective. What in my opinion it all biols down to is did the guy wast his money? This is what he asked. With that I would say it all depends on how yo ulook at it, and what the application is for. Just my thoughts.
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Old Mar 3, 2005 | 11:38 PM
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Like you said, it depends what he wants to use it for. It increases acceleration but not power to the wheels. Power is related to torque and rpm, the flywheel doesn't affect either one of these, nor does it affect drivetrain losses. It is just like removing weight from the car, it does increase power, but it does increase accleration. It is similar to adding power because it would take more torque (power at a given rpm) to accelerate the heavier car.

I think that the lighter flywheel is a good investment for general racing and driving around, although I think that I would personally deal with weight reduction and power mods before going the light flywheel route. I think the lightweight steel (what he got) is the best compromise. The stock ones are heavy and the aluminum ones are too light for a lot of purposes.
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Old Mar 4, 2005 | 01:18 AM
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bottom line is once you try a lightened flywheel, youll never go back to a heavy stock one..
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Old Mar 4, 2005 | 01:59 AM
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Originally Posted by 680RWHP12A
bottom line is once you try a lightened flywheel, youll never go back to a heavy stock one..

AMEN ! Good opinions all around thou.

Robert we have little meets down here by my hood. Jose V benn showing up a couple times. Rene been there couple times too. I got my buddies with turbo duces (Orville's and another homies) and threes meet up there. You should check it out.

-Ryan

Last edited by 1984se; Mar 4, 2005 at 02:01 AM.
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Old Mar 4, 2005 | 07:35 AM
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Originally Posted by 680RWHP12A
bottom line is once you try a lightened flywheel, youll never go back to a heavy stock one..

I did. Hated aluminum flywheel on a stop and go traffic and at launching too. For the money, I would rather just use the 23 lbs flywheel.
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