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effects of light weight flywheel

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Old 10-Nov-2005, 05:11 PM
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effects of light weight flywheel

i was argueing with my firned the other day,
we all know that an engine with a light flywheel will rev up quicker, but will the rpms drop quicker due to less wiehgt? i say yes. his arguement is that because of the less weight the rpms will "float" before dropping. im pretty sure hes wrong
but lets find out
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Old 10-Nov-2005, 05:13 PM
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no it will drop faster because there is less weight meaning less momentum correct?
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Old 10-Nov-2005, 05:37 PM
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I just ordered my clutch/flywheel combo yesterday,...gonna be a long winter looking at it on my bookshelf...lol
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Old 10-Nov-2005, 06:27 PM
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lightened flywheel revs up faster as well as drops faster
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Old 10-Nov-2005, 06:39 PM
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hell yeah its drops hella quick.....i got a 7lb flywheel and it drops alot faster
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Old 10-Nov-2005, 06:53 PM
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yeah the revs definately will drop faster.
Now, has anyone else ever heard that using a lightened flywheel will shorten the life of the engine? And that its harder on the engine because more of the vibrations get transferred to the crankshaft b/c the flywheel is so light.
IMO a lightened flywheel is a good mod, especially if your already droppin' the tranny to replace the clutch. You might loose a little bottom end power, but will gain throughout the rest of the powerband.
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Old 10-Nov-2005, 06:54 PM
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Originally posted by viper
I just ordered my clutch/flywheel combo yesterday,...gonna be a long winter looking at it on my bookshelf...lol
you think you're going to have a long winter? you don't even know the half of it man...
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Old 10-Nov-2005, 07:22 PM
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Haha Chris is going through the waiting period. I waited 9 months to swap my coilover on. Looked at that **** every night down the basement is just mind blowing stupid.

It can drive a man crazy.

Back on topic, I should know how a lightened flywheel feels like come this Sunday.
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Old 10-Nov-2005, 07:23 PM
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Originally posted by Nova_Dust
Haha Chris is going through the waiting period. I waited 9 months to swap my coilover on. Looked at that **** every night down the basement is just mind blowing stupid.

It can drive a man crazy.

Back on topic, I should know how a lightened flywheel feels like come this Sunday.
how light you going??
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Old 10-Nov-2005, 07:29 PM
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Originally posted by Nova_Dust
Haha Chris is going through the waiting period. I waited 9 months to swap my coilover on. Looked at that **** every night down the basement is just mind blowing stupid.

It can drive a man crazy.

Back on topic, I should know how a lightened flywheel feels like come this Sunday.
You should already, you drove my car with the LSD on it. The flywheel was also lightened.
 
Old 10-Nov-2005, 07:48 PM
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Originally posted by Nova_Dust


It can drive a man crazy.

yes.. it can. Especially something like what I just bought.
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Old 10-Nov-2005, 08:08 PM
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So does a lighter flywheel shorten the life of the engine?
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Old 10-Nov-2005, 09:07 PM
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A lightened flywheel will not shorten the life of the engine. Most of the vibrations in the engine are usually dampened by the harmonic balancer or balancers.

B and D = Balancer (built into crank pully)
H and F = Balancers (2 shafts)

When removing harmonic dampeners such as changing your crank pully, (underdrive pully) alot of times you may cause damage to your engine. The vibrations caused by your internal rotating assembly need to exit, and unforturately the brunt of the forces are taken out on other parts (IE: the rod and crank bearings, the crankshaft, oil pump etc.). You may not notice any damage immediatly, however it is happening.

You can reduce the amount of harmonics being produced by balancing your engine.

As far as Lightening the flywheel I don't see too many downfalls:

-possible stalling (not enough rotating mass)
-weakening the flywheel itself (removing too much material)
^^^ have not run into this problem yet!

Other then that It's probably one of my favorite non-forced inducted, easy to do mods.
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Old 10-Nov-2005, 10:12 PM
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Originally posted by DefconDave
... dampened by the harmonic balancer or balancers.

B and D = Balancer (built into crank pully)
H and F = Balancers (2 shafts)

The balance shafts in the H and F motors do nothing to DAMPEN the vibrations of the motor. The balance shafts actually create a vibration of their own which cancels out the vibrations of the engine, which makes a smoother running vehicle overall.
The damper in the crank pulley does dampen engine vibrations, but for a reliability/durability standpoint, not to make a smoother running engine.
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Old 10-Nov-2005, 10:23 PM
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easy to do?!?!?!
I would not call having to drop the tranny an easy to do mod. Like a header or even cams.
But very worth while if you are replacing the clutch, hell for a little more than what you would pay to get your flywheel resurfaced and balanced (which IMO should be done when replacing the clutch), you can get a 7-11lbs new flywheel.
So, you don't think that more strain would be put on the crankshaft/bearings when you use a lightened flywheel? I mean wouldn't the crank take more abuse with less mass to absorb the shock of the clutch engaging?
I am interested to hear more opinions on this because i remember reading a pretty technical article about this somewhere. I completely agree about using a aftermarket crank pulleys unless its one of those fluidamper ones.
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Old 10-Nov-2005, 10:33 PM
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Originally posted by kwikb16a2


how light you going??
4.2kg, I believe.
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Old 10-Nov-2005, 11:02 PM
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DO IT DO IT...

i have a 10 lb one..just rite..not too light not too heavy.. up hills are a bit of pain at times..but doable...
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Old 11-Nov-2005, 04:51 AM
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i'm using a Toda 8lbs flywheel, and the only downfall i find is that the engine idle drops down when i clutch in, and then pulls itself back up a bit.

motor does rev up a lot faster though...works great with tight ratio gearboxes. i was considering the ACT Pro-light too cuz of the cost. it's pretty cheap for what it is...
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Old 11-Nov-2005, 10:07 AM
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Tight ratio gearbox, how tight are we talking here? 4.7FD?
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Old 11-Nov-2005, 01:12 PM
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Originally posted by Nova_Dust
Tight ratio gearbox, how tight are we talking here? 4.7FD?
yup, works great on the JDM ITR! it was great with my 4.4FD gsr as well though..
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