R34 Gtr Advice Please: Power Limit - Nismo Clutch + Dual Mass Flywheel

[iwanta34gtr]

Hi everyone,

I have an R34 GTR and when I bought it a few years ago, the gearbox was rattling loudly.

The cause was a combination of the spigot bearing needing replacing and also because it had a Nismo clutch + lightweight flywheel fitted.

When I had the spigot replaced, I also had the lightweight flywheel removed and a near new standard dual mass flywheel refitted (however the the Nismo clutch was left). The aim of this was to make it quiet (Which it is, and I have been happy with it for the past 2 years).

I am now getting ready to fit the remainder of my mods and aiming for 300 - 330kw.

I believe 3000S-RSR45-E is the Nismo clutch kit I have in the car, with the exclusion of the lightweight flywheel - http://www.nismo.co.jp/en/products/competition/clutch/pdf/clutch05_2.pdf

Will my current clutch setup (with dual mass flywheel) cope with my power goal?

The car is daily driven, so I love my current pedal feel and how it's so quiet - would like to keep it if possible.

Cheers.

Edited January 3, 2014 by iwanta34gtr

[GTRsean]

It will hold 300WKW fine but, if you like launching or going to WSID you will need an upgrade

[iwanta34gtr]

It will hold 300WKW fine but, if you like launching or going to WSID you will need an upgrade

Thanks mate, appreciate it.

[GTRPSI]

I never knew R34 GTR's had dual mass flywheels or anyone made them for them.

Are you sure thats right, its go me scratching my head.....

They were always solid flywheels as far as i ever knew and saw.

If it is dual mass i wouldnt be putting any performance through it.

[533 RYC]

^ THIS!

Where did the dual mass flywheel come from?

I can definately see Nissan using one as a performance limiting device, & to smooth out the torque delivery.

[GTRsean]

R34 GTR and 15 silvias had dual mass flywheels to reduce NVH, especially at idle and low RPM. They are pretty heavy though.

Not sure about other models. Probably Z33's too?

[sinistaGTR]

yeh can confirm the 350z and 34 GTR have dual mass flywheels....

$500 for nismo or Jun forged single mass ones (I went with the Jun item). Def worth the upgrade.

[533 RYC]

sneaky little buggers.

By rights, by swapping to a SMF, bottom end rebalancing should be carried out.

Are the R33 & R34 crankshafts the same? Is it a matter of fitting an R33 balancer when swapping from DMF to SMF?

Dan, any ideas as to the weight difference between the two?

[sinistaGTR]

Um I dont have any figures but the dual mass was FkN Heavy..... and the single mass was far lighter lol.

[GTRPSI]

Just for my own info/education, does anyone have a picture of a R34 Dual mass flywheel and clutch assembly.

Im gobsmacked that Nissan used them on a performance car......

Edit, just researched it and found this thread with some good pics in case anyone else wants to see it....http://www.skylinesaustralia.com/forums/topic/422601-r34-gtr-clutch-flywheel-and-clutch-line/

Edited January 10, 2014 by GTRPSI

[MrStabby]

By rights, by swapping to a SMF, bottom end rebalancing should be carried out.

Why is that? Are R34's externally balanced?

[533 RYC]

Yes they are, as nearly all engines are.

What is the weight difference between an R33 GTR & R34 GTR harmonic balancer? I bet they aren't the same.

When balancing bottom end rotating assembly, everything is needed. Rods, balancer, flywheel & clutch assembly.

Making large weight changes over what it was designed to operate with can introduce excessive torsional frequency changes, more than what the balancer can remove, which can lead to premature bearing failure & the worst case scenario of crankshaft breakage.

Remember, every action has an opposite reaction. Just because you can't see it, doesn't mean its not happening....

[MrStabby]

Yes they are, as nearly all engines are.

What is the weight difference between an R33 GTR & R34 GTR harmonic balancer? I bet they aren't the same.

When balancing bottom end rotating assembly, everything is needed. Rods, balancer, flywheel & clutch assembly.

I was told that almost all motor were internally balanced, except for odd stuff like 400ci chevs.

<quote>

Making large weight changes over what it was designed to operate with can introduce excessive torsional frequency changes, more than what the balancer can remove, which can lead to premature bearing failure & the worst case scenario of crankshaft breakage.

</quote>

True, but that has nothing at all to do with being internally or externally balanced, right?

[Gts-t]

You should balance the balancer, bottom end, and flywheel/clutch separately. This is because over the live of the motor you are likely to need to change the balancer and clutch. This is how the factory does it...... F1 might be different lol

[Gts-t]

Can't say I've ever seen balancing marks on a clutch disc or pressure plate though.

[533 RYC]

Sorry Adam. The majority engines are internally balanced, to a degree. However, there are some factors that have a direct effect upon this.

The length of the crankshaft vs the length of the stroke & offset at a given maximum RPM will determine whether external balancing and/or balance shafts are/is required, for the demands/loads the engine will experience, depending on the extent & level that internal balancing has been carried out to.

example: MOST mass produced, shorter stroke 4 cylinder engines, when balanced INTERNALLY, don't produce enough torsional frequency when balanced to require external balancing for the type of duty they are designed for, hence they only have a crankshaft pulley.

When the length of the crankshaft increases (and whether its an inline or vee engine), so does the torsional frequency. The torsional frequency produced is also dependant on the Ignition system & firing order. Internal balancing will only reduce torsional frequency to a certain point, then, another way has to be introduced to minimize the possibility of crankshaft breakage, hence, a harmonic balancer is added to lessen the frequencies to an acceptable level.

Some manufacturers, like Honda, incorporate a balance shaft mounted below the crankshaft (gear/chain driven) to remove a small amount of vibration between afew hundred RPM. Other manufacturers like Mitsubishi use up to two balance shaft that counter rotate to eliminate vibration. The dirty old 3.8L Buick V6 had a balance shaft in the valley & a harmonic balancer!

A good way to learn about this area is to talk to a vibration analysis expert. Chat to a company that deals with condition monitoring, they can tell you all about torsional frequency.

So, back to my question, does anyone know the weight difference between an R33 & R34 GTR harmonic balancer??

might ring JEM tomorrow & get an answer.....

[MrStabby]

Gavin, I still think you may be confusing engine balancing (which is nothing to do with what the harmonic "balancer" does on an internally balanced engine) with the crankshafts resonant torsional frequencies (aka harmonics), which is what the harmonic "balancer" dampens. The firing order etc interacts with the resonant vibration to increase or decrease its magnitude, depending on when the rods hit the crank as it twists back and forth. This stuff is known as constructive and destructive interference on simple harmonic motion (or something like that). I did study this stuff around 20 years ago, but i have a terrible memory, so i could be mistaken.

Harmonic balancers are as stupidly named as shock absorbers. Each should be called vibration dampeners, as that correctly describes their function.

[GTRPSI]

Can't say I've ever seen balancing marks on a clutch disc or pressure plate though.

Ive seen many pressure plates with balance holes drilled into them.

We are taking our bottom end to duggan balancing next week, crank is balanced, then harmonic balancer and flywheel are added and balanced then pressure plate.

The whole idea is you need to be able to swap the flywheel on its own or maybe just replace your clutch kit so you dont want to throw out the balance of everything else because you are changing just 1 part.

[MrStabby]

Ive seen many pressure plates with balance holes drilled into them.

We are taking our bottom end to duggan balancing next week, crank is balanced, then harmonic balancer and flywheel are added and balanced then pressure plate.

The whole idea is you need to be able to swap the flywheel on its own or maybe just replace your clutch kit so you dont want to throw out the balance of everything else because you are changing just 1 part.

That makes a lot of sense to me. You would only ever want or need to balance the whole balancer/crack/flywheel etc together if the engine was externally balanced.

[533 RYC]

sneaky little buggers.

By rights, by swapping to a SMF, bottom end rebalancing should be carried out.

Are the R33 & R34 crankshafts the same? Is it a matter of fitting an R33 balancer when swapping from DMF to SMF?

Dan, any ideas as to the weight difference between the two?

Yes they are, as nearly all engines are.

What is the weight difference between an R33 GTR & R34 GTR harmonic balancer? I bet they aren't the same.

When balancing bottom end rotating assembly, everything is needed. Rods, balancer, flywheel & clutch assembly.

Making large weight changes over what it was designed to operate with can introduce excessive torsional frequency changes, more than what the balancer can remove, which can lead to premature bearing failure & the worst case scenario of crankshaft breakage.

Remember, every action has an opposite reaction. Just because you can't see it, doesn't mean its not happening....

I was told that almost all motor were internally balanced, except for odd stuff like 400ci chevs.

<quote>

Making large weight changes over what it was designed to operate with can introduce excessive torsional frequency changes, more than what the balancer can remove, which can lead to premature bearing failure & the worst case scenario of crankshaft breakage.

</quote>

True, but that has nothing at all to do with being internally or externally balanced, right?

Gavin, I still think you may be confusing engine balancing (which is nothing to do with what the harmonic "balancer" does on an internally balanced engine) with the crankshafts resonant torsional frequencies (aka harmonics), which is what the harmonic "balancer" dampens. The firing order etc interacts with the resonant vibration to increase or decrease its magnitude, depending on when the rods hit the crank as it twists back and forth. This stuff is known as constructive and destructive interference on simple harmonic motion (or something like that). I did study this stuff around 20 years ago, but i have a terrible memory, so i could be mistaken.

Harmonic balancers are as stupidly named as shock absorbers. Each should be called vibration dampeners, as that correctly describes their function.

100% agree with you on that. Vibration Dampener is the correct terminology. As for for shocks, they should be called Oscillation Dampeners.

Ive seen many pressure plates with balance holes drilled into them.

We are taking our bottom end to duggan balancing next week, crank is balanced, then harmonic balancer and flywheel are added and balanced then pressure plate.

The whole idea is you need to be able to swap the flywheel on its own or maybe just replace your clutch kit so you dont want to throw out the balance of everything else because you are changing just 1 part.

That makes a lot of sense to me. You would only ever want or need to balance the whole balancer/crack/flywheel etc together if the engine was externally balanced.

Firstly, sorry to iwanta34gtr for hijacking his thread, this discussion needs it's own thread.

Again, bottom end balancing should be carried out as a complete rotating assembly, correct?

If you dramatically change 1 part (eg reduce your flywheel weight by half - lets say 6kg), will it not throw out the balance of the bottom end? Yes it will.

Dual mass flywheels are designed to deliver a smoother power delivery with less vibration, correct?

So ineffect, do dual mass flywheels in a way, function the same as a vibration dampener? I would say yes.

So, by removing the dual mass flywheel & fitting a single mass flywheel are you ineffect allowing a higher torsional frequency to occur at certain points in the rev range? I think so, hence my original statement.

Adam, why would you only balance a rotating assembly if it was externally balanced? Any rotating assembly should be balanced regardless of how it is balanced!