Flywheel comparison and review thread

[tom_deas]

Steven pretty much explained it, but there's one occasion where a heavier flywheel can store more energy and release it. The storing happens when you rev the engine with the clutch pedal down. And the release happens when the clutch is slipping. Once it grabs, there's no extra stored energy anymore and you won't be losing midrange torque or anything else either.

+1 steven pretty much got it all there. as for the heavier flywheel bit - feel free to google "KERS". im sure im strictly not allowed to say anything more than that so my lips are sealed, but yes  s:) s:)  i find it all interesting anyway...

[Steven Velocity]

Steven pretty much explained it, but there's one occasion where a heavier flywheel can store more energy and release it. The storing happens when you rev the engine with the clutch pedal down. And the release happens when the clutch is slipping. Once it grabs, there's no extra stored energy anymore and you won't be losing midrange torque or anything else either.

I agree with Tem, a heavier flywheel (remembering that gravity is a constant) has more mass, thus, more inertia, and more potential energy, the same as a freight train has more mass, thus, more inertia, and more potential energy than a Spyder. If you accelerate the flywheel without using any of that energy to also accelerate the vehicle (rev engine, clutch pedal down), then a heavier flywheel will have more inertia and carry more energy than a lighter one, the same as if you let the freight train coast down hill before turning on the engines. The heavier flywheel will then take longer to overcome its inertia and burn off its energy (release clutch at whatever engine rpm that makes the most torque) to try to come to rest, which in real life terms is usually matching the speed of the engine with drivetrain. If you were drag racing and revved the engine up to as fast as you could, (clutch in) and had the heaviest flywheel your engine could accelerate taking into account the power to weight ratio of the whole vehicle, the car would launch the quickest (very fast 60ft times) when you let go of the clutch because the energy in the flywheel is essentially free energy in addition to the energy from the engine accelerating the car. Once the energy in the flywheel is used up (engine rpm matched the drivetrain rpm) then the engine would have to overcome the inertia of the heavier flywheel again to accelerate the whole car, and this compounded by changing gears, would make for a much slower overall run.  So the lightest flywheel with the least amount of inertia will still make a car faster over a longer than a few feet distance.

That's with N/A engine though and turbo does shuffle the situation some. With a turbo, a heavier flywheel can actually make it spool up with lower revs, because of the extra load. That's assuming you floor it around idle and won't downshift. And that can give you extra torque before the turbo gets to set pressure. The confusing part is that even a turbo car with lighter flywheel is faster in reality with less torque and the reason is that it gets to the higher revs so much faster than the one with heavier flywheel. And if you really want to be slower, but make more midrange torque, you can always drive with the handbrake on or get a heavy passenger. It'll do the same as a heavier flywheel.  s;) s;)

Again I agree with a slight amendment. With a heavier flywheel on a turbo engine the turbo will spool up and reach a set pressure in lower revs giving you more engine torque before a set rpm. You correct that this is because with the extra load it takes longer to increase engine rpm, so still results in a slower car than one with a lighter flywheel.

  s:mrgreen: :mrgreen: s:mrgreen:  
Steve

[Anonymous]

Steven pretty much explained it, but there's one occasion where a heavier flywheel can store more energy and release it. The storing happens when you rev the engine with the clutch pedal down. And the release happens when the clutch is slipping. Once it grabs, there's no extra stored energy anymore and you won't be losing midrange torque or anything else either.

+1 steven pretty much got it all there. as for the heavier flywheel bit - feel free to google "KERS". I'm sure I'm strictly not allowed to say anything more than that so my lips are sealed, but yes  s:) s:)  i find it all interesting anyway...

Why do I keep getting credit for stuff I didn't write ?? This is what identity theft must feel like !

[Anonymous]

'Cos Chris mucked up the quotes. Don't panic, 'tis only a slip of the keyboard.

ZOMG the whole is coming to an end!

s;) s;)   s;) s;)   s;) s;)

[Anonymous]

Well, that took a while, but I got it   s:D s:D

[ChrisGB]

'Cos Chris mucked up the quotes. Don't panic, 'tis only a slip of the keyboard.

ZOMG the whole is coming to an end!

s;) s;)   s;) s;)   s;) s;)

Brain fade. It must be the noise  s:twisted: :twisted: s:twisted:  

Chris

[kanujunkie]

Can you change the flywheel on it's own? I know there's obvious benefits to doing the clutch while you're there, but is there any mechanical reason you can't?

no, no reason at all, you just treat it as a clutch removal and refit

[aaronjb]

4kg for the whole setup would be crazy Aaron..It would mean that the flywheel is about 1,5kg..  s:D s:D  

 Here is the exact weight of the Ogura 2zz setup: 9 kg

Ahh thanks Christopher - we weighed both, maybe the 4Kg was the weight it drops vs. the stock setup  s:) s:)  It was .. well it wasn't that long ago, I just have a very short memory!  s:lol: :lol: s:lol:

[Christopherathens]

I just have a very short memory!  s:lol: :lol: s:lol:

Me too Aaron!!That's why i take pictures..  s:lol: :lol: s:lol:    s:lol: :lol: s:lol:

[LordTakuban]

The stock flywheel is 16lbs (7.25747792 kg according to google) IIRC.  I have the Fidanza flywheel and ACT Clutch.  I don't have any comparison data other than it's easier to stall with the lighter flywheel and the rpms raise and drop quicker.  A dyno of before and after would have been nice to see how much WHP would be recovered from the lighter flywheel, but I didn't have the means to do that when I had it done.

[ChrisGB]

The stock flywheel is 16lbs (7.25747792 kg according to google) IIRC.  I have the Fidanza flywheel and ACT Clutch.  I don't have any comparison data other than it's easier to stall with the lighter flywheel and the rpms raise and drop quicker.  A dyno of before and after would have been nice to see how much WHP would be recovered from the lighter flywheel, but I didn't have the means to do that when I had it done.

Subjectively, how much difference does it make to acceleration, particularly in lower gears? Is it noisy / rattly at idle?

Chris

[LordTakuban]

Subjectively, how much difference does it make to acceleration, particularly in lower gears? Is it noisy / rattly at idle?

Chris

It's hard to say how much quicker it accelerated.  It didn't feel Much faster.  I had my ACT clutch installed at the same time and that was the biggest difference I noticed.  There is no more or less noise with the flywheel.  The car may even start a split second quicker.  The science/theory is there that reducing the rotating weight should free up some power to make it to the wheels.  I'm happy with my purchase.  Since I was getting a new clutch, I figured I might as well just swap out the flywheel at the same time.  s;) s;)

[Kool PT]

just been on an internet auction site and seen exedy oem clutch & fidanza flywheel for £252...  s:shock: :shock: s:shock: ...seems like a good price?

[markiii]

depends if your a fan of fidanza, peopel either love em or hate em,

and if thats an oem clutch I'd be tempted to upgrade it whilst your in there.

but yes price is very good

[loadswine]

I really like the Fidanza that I have, but its not on a 1zz, but it is very light compared to the stock item, maybe 50% of the weight.  This seems to go very nicely with the ACT clutch for me. My first attempt at owning a car with lightweight fly and 6 puk clutch, got used to it quite easily.

[Kool PT]

interesting - doubt this price will be around once i've got the funds to pick em up though. I do definitely plan on getting it sorted out though before next summer.

[evileye_wrx]

Don't forget to add the same again for fitting.

+1 on upgrading the clutch too.  Seems pointless not to.

Phil

[ChrisGB]

depends if your a fan of fidanza, peopel either love em or hate em,

and if thats an oem clutch I'd be tempted to upgrade it whilst your in there.

but yes price is very good

Hi Mark

When you say love em or hate em, what is it about them that polarises people?

Chris

[markiii]

quality, I have heard they aren;t teh best made pieces of kit, whihch is one of teh reasons I elected to purchase differently, it may or may not be accurate but the last thing you want is failure of something spinning that fast right behind you

[uktotty]

Anyone seen/purchased one of these?

[Anonymous]

Just put me right here; a lightened flywheel is all about revving quicker so you get to the power faster.
What you lose out on is torque so you have to keep the revs high and make the gear changes spot on (ie keep it on cam).
So, lightened flywheel with turbo (or vice versa really) is a good way to go?

[ChrisGB]

Just put me right here; a lightened flywheel is all about revving quicker so you get to the power faster.
What you lose out on is torque so you have to keep the revs high and make the gear changes spot on (ie keep it on cam).
So, lightened flywheel with turbo (or vice versa really) is a good way to go?

A lightened flywheel simply means less weight is being accelerated by the engine. You do not lose any torque, but you get the revs rising faster when you drive, or when you rev match or heel 'n toe.

Cannot see any reason why you would not go for light flywheel on a turbo.

The picture in the post above is a lightened pulley. That may or may not have negative effects on engine life.

Chris

[Anonymous]

If you go Ogura - just make sure you are prepared for the continual 'you cars broken mate' stares & comments....

[wbarrwebster]

Hi,

I bought a lightened pulley wheeel the last time I was on Holiday in Oz, the actual wheeel came fron New Zealand, ( following this so far?) Anyway, after consulting someone in the Forum decided not to fit at the end of the day.

From memory the suggestion was that there could be a harmonics (?) issue with the lightened Pulley vs the Crankshaft. I did recontact the guy downunder who suggested it would not be an issue unless I was pulling 300 bhp!

The threat was that it could screw up the crank over a period, to my mind the possible problem out weighed and possible benefit!!

Ahem!

B