[Mk2] [Turbo] Effects of a lighter flywheel?

[Kenny-Boost]

Out of interest guys i've been looking around the net at lighter flywheels (cause my clutch will need doing soon) and i know a lighter flywheel will make the engine rev free-er

However how does it affect the decereration of the car when coasting?

How does it affect acceleration of the car?

How does it affect the torque?

How does it affect the fuelling (will map need tweaked on FC i.e. richer / leaner?)

Much appreciated guys - looking forward to a good thread with this question

[rowan_rev1]

in theory the engine will require less power to turn the transmission with the flywheel being lighter but this can also be a problem.
the good points are that the engine will rev easier and could effect your acceleration in a good way (up to a point dont expect a second knocked off!)

the engine doesnt have to waste as much power to make power

the bad points unfortunatly out weight the good points

if you get try to use "extra's" like air conditioning and other things that run off crank the engine is more likely to stall. i couldnt use my s13's a/c when stationary as there wasn't enough momentum coming form the flywheel to keep it all going properly.

you'll notice you cant carry as much torque up hills and you'll slow down quicker

during gear changes the engine will spool down quicker and will become more of a strain on the rest of the drive train

but tbh if they weren't that good would big manufacturers/tuners put them on all of their race cars?

my opinion would be do it!

[Kenny-Boost]

Confusing stuff, i always blip on up and downchanges to try to RPM match, this will obviously require to recalibrate my right foot lol

as for AC well, mine leaks so only works for about 3 days at a time before needing a recharge ha ha, i'll need to get that seen to.

i heard from a tuner the whole thing about hills but his arguement is the turbocharger will more than make up for any torque issues going up a hill?

[rowan_rev1]

well my other point i was going to make was "just turn up the boost!" but if your already high on boost maybe its not a great idea to go whacking it up!

if you go for a basic fidanza wheel (about 7 pounds instead of the OEM 12-14 pounds) then your not really going to notice to many of the downsides as the flywheel isnt too light. it's the ones that weigh 2 pounds that cause all the trouble really!

[Kenny-Boost]

Hmm i thought the fidanza ones were lighter than the chromoly ones?

How much does a fidanza one for a 3S-GTE weight?

Looking at the chromoly ones they seem about the 5.5Kg mark

[^Trickster^]

Fidenza ones are crap in my opinion, seen loads of them fall to pieces, im running a full chrome moly XTD with a spec stage 3 clutch, revs a little more freely but theres no real noticable difference from the stock flywheel in my opinion. I only fitted one so i had a nice clean surface to mount my clutch to.

Flywheel has seen about 10k miles and hasnt had a problem, that include 9 12 second drag runs on track and a fair few on the street

Graeme

[jmachling]

My Fidanza is still going strong after 15k - no issues at all. I don't tend to drag it much though.

A/c works fine and it's very driveable. You do need to give it a few more revs than the standard flywheel, but it's a very easy to adjust to driving style.

[EarL]

Well, I've got one of those "crap" Fidanza FW's on mine, and I noticed a fair bit of difference in pick up. The motor definately spins up quicker, and torque hasn't suffered at all.

EarL.

[Kenny-Boost]

My mates fidanza warped on his SX, i'm not buying one anyways i was just wondering if they weight more or less than the chromoly ones.

Quite like the looks of the JUN one its chromoly

[pintovit]

The other day saw this guy talking in a tuning event and he was quite clear about flywheels (at least it made sense to me).
There are applications you need lighter flywheels and there are others where you may need heavier ones.

For off-roading, you don't want the engine to rev up and down fast. You want a engine that keeps its momentum on a constant rate so you can modulate traction easier.
For track, you want the engine response to be has immediate as possible. So light flywheels...
It won't have any more or less torque/power. It's only when changing momentum (accelerating or decelerating) that you'll see the difference with the engine reacting faster because the rotating mass is smaller.

Imagine that you have to rotate a wheel using pedals (like in a bicycle). You're body produces a amount of torque that doesn't change (at least in a 10 minutes gap). You can only rotate the wheel until a certain RPM because you'll lose your coordination (red line! ).
If the wheel is very light you'll make it spin really quickly and stop it in a short amount of time.
If the wheel is very heavy it will be the opposite. However, you'll probably achieve the same RPM and you're producing the same power.

Sorry for the long thread...

Cheers,
Vítor

[Scott Barton]

Have had a Fidanza on mine for nearly 4 years now. Dragged it, raced it and used it pretty hard....no problems reported.
For info i have a Fensport Helix ceramatallic clutch jobbie...

[Leon.]

My Ogura flywheel's great. Much freer in the revs, blips much more easily and the rev don't plummet when you change gear so when you disengage the clutch the revs are at the perfect level - ultra smooth gear changes too

Less strain on the transmission will cost you less too in the long run.

[rmarr1980]

Running a Jun lightweight flywheel on mine very well machined and made very light and love the way the engine reacts with it fitted have noticed just the occasional light dip in the revs at traffic lights etc. But tested up a nice steep hill near cadwell park and she just pulled all the way up.

Get one fitted its also less strain on the crank components and bearings.

[Caribbean_Blue]

Another thumbs up here for a Fidanza flywheel.

I have used an abused the only thing that has let me down was the clutch.

Pukka upgrade IMHO.

Reece

[pintovit]

Taking the topic (I hope you don't mind the slight thread hijack), for those of us less fortunate ($$$) did anyone tried to take the stock flywheel and have it machined to make it lighter?

Some people told me I could do that but I'm not very convinced of the outcome...

Thanks.

Regards,
Vítor

[Kenny-Boost]

i know of a few lads in the vauxhall circle who have done that, i think you could probably save some weight but probably not too much before it would end up too weak to save loads because the material used is heavier than the aftermarket ones

[Antstarr]

To report back from my HKS flywheel and clutch change update. Engine does rev quicker, needs only a slight tad more pedal and transmission is smoother to change.

[Kenny-Boost]

Ant - what clutch did you go for?

so you did get that flywheel off ebay you were showing me? nice one!!

how do you mean it needs more pedal? under what situation?

[Antstarr]

Needs more pedal in general but results are more noticable.
I just got a standard exedy clutch...yea it was worth it as they discontinued the HKS flywheel and apparantly my stock flywheel was pretty messed up.

[Kenny-Boost]

Cool, sounds like fun, think i'm going to go with an HKS or JUN one, the tuner i'm using has seen a few fidanza's warp, so he's asked that unless i particulalry want a fidanza to go for a chromoly item - i'm not fussed so i'll go with his judgement