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Low Inertia Flywheel= Reliable or not

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Old May 17, 2004 | 09:24 AM
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Default Low Inertia Flywheel= Reliable or not

When i bought my 350z I had yet to drive it. I had just parked a 2002 rsx type s equipped with an 8 low inertia flywheel from comptech, exaust manifold, cold air intake and grounding mods. That sucker revved!! The first thing i noticed from driving the z was the unmaskable and overwheming torque, Its needless to say i took surface streets home. But as i approached the first traffic light i leftthe car in neutral and gave it a ritualistic tap of the gas. Vrooom ANd as i was expecting a quick decline in decibels i was surprised with a long dragged out drone of an engine decceleration that just wouldnt quit.

"Man thats a heavy flywheel" my words exactly. Later i learned that the 350z was epuiped with a duall mas flywheel with two discs connected by a bunch of rubber and springs? why, the high tourque capacity tranny rattled and made noises so nissan had to dampen the vibrations to avoid having their brand new shiny orange sports car form soinding like a 20 year old brown food truck that was bought at a UPS auction.HAHA go figure. I don't really care that much although i had it when m body creaks goign over grade changes so i can't speculate.
The thing is, i like how a car behaves when it is equipped with a flywheel that has a low moment of inertia. As i have learned inertia has to do with weight and diameter of the flywheel.

I have also learned that the crank pulley has a harmonic dampener for the crankshaft. My question is this. Does my factory equipped dual mass flyweel dampen my engine vibrations as well. And if so how much, can i afford replacing it with a tilton flywheel and still have enough dampening be povided by my factory crank pulley. Will my transmission fail due to the absense of dampneing by the new flywheel. And lastly i understand that the vq35 in the z is internally balanced, will this modificaiton still through off the balance or does balance have to do with rotatioj and not load on the flywheel side of the crank. Peace and Thank You
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Old May 17, 2004 | 10:40 AM
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good question, i have been wondering the same thing.
anyone?
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Old May 17, 2004 | 10:49 AM
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Crank pulley does not act as an harmonic balancer. It has a rubber damper to decrease belt noise. As you stated correctly, the engine is internally balanced.

The flywheel will not affect the engine balance. As stated correctly, the dual mass flywheel was designed to reduce chatter from the tranmission into the passenger cabin. Besides NISMO makes a single mass light weight flywheel. They would not build a part that would damage the Z. The flywheel is R-tune part because it is not "civil" (Nissan's ridiculous measure of S-tune vs.. R-tune).
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Old May 17, 2004 | 05:37 PM
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that really makes me wondering... will the flywheel really give so much acceleration power? I do admit that the flywheel does give faster rev when the engine isn't engaged with the clutch. But once the flywheel is engaged with the whole drive train which is moving the car, the flywheel is actually carrying all the drive train weight (drive shaft, wheels...ect), isn't it? So does that mean changing to light weight mag wheels will have the same effect as changing the flywheel or even better? we cannot save a lot of weight on the flywheel, but on those 4 wheels, the weight saving can be substantially huge...

If I am wrong, can someone correct me here? I am just confused...

cheers,

richie
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Old May 17, 2004 | 09:58 PM
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People on the board have dynoed their cars with light weight Volks and put up higher numbers. But because of the gearing and final drive the flywheel has the larger effect.
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Old May 17, 2004 | 10:06 PM
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shortcut3d..... sorry... I don't really get what you meant by gearing and final drive?

thanks!

cheers,

richie
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Old May 17, 2004 | 10:32 PM
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I think what he means is the RPM at which flywheel rotates compared to your wheels. Even in 6th gear the wheels rotate at 1/4 (I think) of the speed of the flywheel. This is why the gains are a lot smaller if you change the wheels compared to the flywheel.
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Old May 17, 2004 | 11:15 PM
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Originally posted by Z350Lover
So does that mean changing to light weight mag wheels will have the same effect as changing the flywheel or even better? we cannot save a lot of weight on the flywheel, but on those 4 wheels, the weight saving can be substantially huge...
cheers,richie
Remember, two wheel rear drive car so only the rear wheels really matter weight wise.
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Old May 17, 2004 | 11:22 PM
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nuff:

Thanks for clearing that up for me mate!

cheers,

richie
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Old May 18, 2004 | 06:35 AM
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do a search for the 8lb Tilton Lightweight Flywheel/Clutch Combo by Jason of performance nissan. He posted a video going around a track, and you can definetly tell that the acceleration is on another level. Jason also posted a couple other videos displaying revving the engine with the tiltion flywheel, and displaying how it was a streetable clutch. When he gets on it though, its a whole nother beast. The next mod hands down for me is the tilton flywheel clutch combo.
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Old May 18, 2004 | 03:37 PM
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If you use a lighter wheel and the same diameter as stock, you will gain HP, If you use a lighter wheel but larger diameter, you will loose HP. The same goes with the brake rotors. The flywheel frees up the power your motor needs to get that big heavy flywheel and clutch spinning. You don't really gain HP to the wheels but ALOT more engine response which seems like more HP.
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Old May 18, 2004 | 09:18 PM
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Originally posted by Z350Lover
that really makes me wondering... will the flywheel really give so much acceleration power? I do admit that the flywheel does give faster rev when the engine isn't engaged with the clutch. But once the flywheel is engaged with the whole drive train which is moving the car, the flywheel is actually carrying all the drive train weight (drive shaft, wheels...ect), isn't it? So does that mean changing to light weight mag wheels will have the same effect as changing the flywheel or even better? we cannot save a lot of weight on the flywheel, but on those 4 wheels, the weight saving can be substantially huge...

If I am wrong, can someone correct me here? I am just confused...

cheers,

richie
your right about the wheels
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Old May 19, 2004 | 12:44 AM
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I am curious about the flywheel issue myself.

Lets not talk about the crank pulley issue or internally balanced engine crap. There have beem countless posts on this and the subject has been beaten to death with no definitive answer. Conclusion on that is that sure maybe it wears on the car a little more but it will not noticeably decrease engine life.

About the flywheel though. Why would Nissan use this heavy piece of junk to mediate between the engine and tranny??
As far as I have heard it is just there to decrease gear noise and enhance drivability.
Will switching to a JWT or a Tilton, shorten the tranny life? If not then what is the cause of all that chatter? Porsches have similar stats and dont have to deal with this crap.
Why did they give the Z a diesel milk truck tranny?
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