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2016 Jazz Blue A8 Scat
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Discussion Starter #1
Anybody tried a lightweight flywheel? Looks like a good mod for about $400-500.
 

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Its not a mod for an engine that is stock. It changes the formula for acceleration! Installing a lightweight flywheel doesn't decrease torque, but it does decrease inertia, meaning more torque will be needed to break traction with a clutch-kick (drifting or burning out), or to accelerate a vehicle off the line during a launch (drag racing, daily driving). Also RPM's go up faster making shorter shift's. Which may help a race car but not much use on the street.
 

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Discussion Starter #3 (Edited)
Its not a mod for an engine that is stock. It changes the formula for acceleration! Installing a lightweight flywheel doesn't decrease torque, but it does decrease inertia, meaning more torque will be needed to break traction with a clutch-kick (drifting or burning out), or to accelerate a vehicle off the line during a launch (drag racing, daily driving). Also RPM's go up faster making shorter shift's. Which may help a race car but not much use on the street.
I know this is the conventional wisdom, but in the one car I owned that had an aluminum flywheel, it was easier to launch consistently on street tires and pulled harder from a roll and had a higher MPH trap speed.

Would have been interesting to do a back to back chassis dyno comparison.

The only negative I experienced was that the car was slightly more difficult to drive on a daily basis - requiring a little more clutch slip and skill for smooth take-offs. Once I got used to it, no big deal. Maybe the clutch only lasted 90% as long as it would have otherwise?

I know different cars may respond differently to modifications, and Challengers are heavy cars, so that is why I was asking if anyone had tried it.
 

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It's a very interesting prospect actually. I've been thinking about trying to reduce weight in every way possible. This is something that I may consider doing with my car, once I swap my clutch next year.
 

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2014 Dodge Challenger R/T Blacktop
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Currently looking for a lightweight flywheel as well. I generally hate the ridiculous time it takes for the 5.7 to "rev down." Used to have a 9 lb Tilton race clutch + flywheel on my Infiniti G35 and it was ridiculous. It revved like a sports motorcycle! The race clutch was ridiculously had to drive, however, given that you have to basically be launching at every light/stop. I'm interested in just the flywheel piece of this equation, though, as it sounds better and the engine has way more pep.

I generally thought lighter flywheel/drive train components = quicker acceleration, but loss in top speed. I'll take accel. over top speed, because that's truly useless for a street car.

Any thoughts? Am I totally wrong on this? Anyone know of a brand that works as a direct flywheel swap with our Tremec TR-6060s? My speed shop is looking into this for me, so if I remember, I'll post the brand.
 

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Currently looking for a lightweight flywheel as well. I generally hate the ridiculous time it takes for the 5.7 to "rev down." Used to have a 9 lb Tilton race clutch + flywheel on my Infiniti G35 and it was ridiculous. It revved like a sports motorcycle! The race clutch was ridiculously had to drive, however, given that you have to basically be launching at every light/stop. I'm interested in just the flywheel piece of this equation, though, as it sounds better and the engine has way more pep.

I generally thought lighter flywheel/drive train components = quicker acceleration, but loss in top speed. I'll take accel. over top speed, because that's truly useless for a street car.

Any thoughts? Am I totally wrong on this? Anyone know of a brand that works as a direct flywheel swap with our Tremec TR-6060s? My speed shop is looking into this for me, so if I remember, I'll post the brand.
Flywheel weight doesn't affect top speed.

It can help acceleration perhaps but a few pounds lighter flywheel vs. 3000lbs (or more) car one wonders just how much a lighter flywheel can contribute to any improvement in acceleration.

The car can be more difficult to "launch" even in just everyday driving. I have no Dodge manual transmission experience but with my other cars with the factory flywheel I relied upon the energy in the flywheel to get the car moving with minimal increase in RPMs and minimal clutch slippage. A lightweight flywheel may require more RPMs and more clutch slippage. Not the end of the world if one can adapt but it will probably shorten clutch (and possibly flywheel) service life.

The engine can lose RPMs quicker between shifts so one needs to speed up his shifting. Trouble is the shift linkage/transmission may not be able to accommodate a faster shift. The transmission has to be heavy duty to withstand the stresses the engine puts to it and this means the shift linkage and all the hardware the shift linkage has to move around is heavier and it just takes time to move this stuff around. If one forces a shift this puts more wear and tear on the shift linkage, the shift forks, the synchros.

No experience -- direct or second hand with Dodges -- but some second hand info regarding Porsche cars fitted with lightweight flywheels. Some Porsche owners went with a lighter flywheel. Some reported wonderous benefits but others not so much. Guess it depends upon what one is looking for, what one expects, is willing to put up with.

There is another problem, though I don't think this applies to the Dodge vehicles, and that is in some cases -- Porsche at least -- the flywheel also acts as crankshaft dampener. Replacing the factory flywheel with a solid albeit lighter flywheel puts extra torsional stress on the crankshaft. At least one noted Porsche engine builder advised against fitting a lightweight flywheel because of this.

While a lightweight flywheel is lighter than a factory flywheel the difference may not be that big. There's a balance between fitting a humongous heavy flywheel vs. something daintier. In an effort to decrease car weight and help improve efficiency factory flywheels could have been put on a diet. One might want to consider just how much weight savings there is to be had between a factory flywheel vs. a lightweight flywheel.

To what level the change to a lightweight flywheel affects driveability of the car one can only know by experiencing this first hand.
 

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Flywheel weight doesn't affect top speed.

It can help acceleration perhaps but a few pounds lighter flywheel vs. 3000lbs (or more) car one wonders just how much a lighter flywheel can contribute to any improvement in acceleration.

The car can be more difficult to "launch" even in just everyday driving. I have no Dodge manual transmission experience but with my other cars with the factory flywheel I relied upon the energy in the flywheel to get the car moving with minimal increase in RPMs and minimal clutch slippage. A lightweight flywheel may require more RPMs and more clutch slippage. Not the end of the world if one can adapt but it will probably shorten clutch (and possibly flywheel) service life.

The engine can lose RPMs quicker between shifts so one needs to speed up his shifting. Trouble is the shift linkage/transmission may not be able to accommodate a faster shift. The transmission has to be heavy duty to withstand the stresses the engine puts to it and this means the shift linkage and all the hardware the shift linkage has to move around is heavier and it just takes time to move this stuff around. If one forces a shift this puts more wear and tear on the shift linkage, the shift forks, the synchros.

No experience -- direct or second hand with Dodges -- but some second hand info regarding Porsche cars fitted with lightweight flywheels. Some Porsche owners went with a lighter flywheel. Some reported wonderous benefits but others not so much. Guess it depends upon what one is looking for, what one expects, is willing to put up with.

There is another problem, though I don't think this applies to the Dodge vehicles, and that is in some cases -- Porsche at least -- the flywheel also acts as crankshaft dampener. Replacing the factory flywheel with a solid albeit lighter flywheel puts extra torsional stress on the crankshaft. At least one noted Porsche engine builder advised against fitting a lightweight flywheel because of this.

While a lightweight flywheel is lighter than a factory flywheel the difference may not be that big. There's a balance between fitting a humongous heavy flywheel vs. something daintier. In an effort to decrease car weight and help improve efficiency factory flywheels could have been put on a diet. One might want to consider just how much weight savings there is to be had between a factory flywheel vs. a lightweight flywheel.

To what level the change to a lightweight flywheel affects driveability of the car one can only know by experiencing this first hand.
Hmm.. really interesting insights actually. Sounds like maybe getting lightweight FW on the Challenger may make it a complete pain to drive considering the mass. Like I mentioned in my previous post, driving with a racing clutch and flywheel was kind of annoying over time. And if you feather it to avoid launching everywhere you go, it basically eats your clutch in about a month. Definitely don't want that experience on my Chally, which is my daily. But I would definitely enjoy quicker revs on the engine.

Oh, in terms of "increased" accel., I was thinking the rotational mass of the FW being lighter (obviously depends on how much lighter than stock) helps spool up the whole drive train quicker. Your engine just has to do less work getting less mass to spin in general.
 

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Hmm.. really interesting insights actually. Sounds like maybe getting lightweight FW on the Challenger may make it a complete pain to drive considering the mass. Like I mentioned in my previous post, driving with a racing clutch and flywheel was kind of annoying over time. And if you feather it to avoid launching everywhere you go, it basically eats your clutch in about a month. Definitely don't want that experience on my Chally, which is my daily. But I would definitely enjoy quicker revs on the engine.

Oh, in terms of "increased" accel., I was thinking the rotational mass of the FW being lighter (obviously depends on how much lighter than stock) helps spool up the whole drive train quicker. Your engine just has to do less work getting less mass to spin in general.
While the mass of the lightweight flywheel is less than the factory flywheel it is less by just a few pounds. The engine has to turn the flywheel but also the transmission and well move the entire vehicle which weighs thousands of pounds.

There is I guess a theoretical gain in acceleration to be had from the lighter flywheel but I doubt it would be measureable.

There will be almost certainly an impact to the car's driveability when (if) the car is used in everyday driving.
 

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While the mass of the lightweight flywheel is less than the factory flywheel it is less by just a few pounds. The engine has to turn the flywheel but also the transmission and well move the entire vehicle which weighs thousands of pounds.

There is I guess a theoretical gain in acceleration to be had from the lighter flywheel but I doubt it would be measureable.

There will be almost certainly an impact to the car's driveability when (if) the car is used in everyday driving.
Yeah, I think I'm going to scrap that idea if people legitimately are saying it is difficult to get the car moving with a lighter flywheel. I don't want to be doing clutch drops at every stop. It's unfortunate, however, as I absolutely hate how long it takes for our engines to rev down after pumping the gas a bit. There's even a whole thread dedicated to tuning the manifold gate to close quicker, because for some reason it stays open for quite a while after revving the engine.

I miss having a really quick rev on my old car with an 11 lb flywheel. It was almost motorcycle-like.
 

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Yeah, I think I'm going to scrap that idea if people legitimately are saying it is difficult to get the car moving with a lighter flywheel.

It shouldn't. Less weight means less inertia meaning easier to move. A fly wheel is used to increase rotational inertia to prevent sudden changes in speed. So a lighter fly wheel should cause it to accelerate and decelerate easier. If anything, it means your car will be more jerky during acceleration changes.
 
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