lightened flywheel

[johl]

basically i have 2 clutch options to choose from and i also want to get a lightened fly wheel. i can get an exedy sports tuff cushioned button kit for around 400 but will have to either buy a lightened fly wheel or get mine machined to make it lighter but it will still be around 2kg heavier than the after market fly wheel. or i can bite the bullet and get a cusco setup including flywheel for around a grand. when i searched for info on this i read that u shouldnt really have a max light fly wheel with a turbo/ supercharged vehicle as they need the inertia of a heavier fly wheel to make more boost. i have a gze so which way should i go?
also please dont +1 for cusco or +1 for ajps as i know they are the shizz but i just want to know which is best for my application which will be a daily driver and track bitch.
cheers johl

[Hen is a total nutcase]

Don't machine your stock flywheel to lighten it. They then have a tendency to explode at high revs.

A light flywheel will be an improvement on any car. Not as needed on FI engines as you have more options to increase power to make up for a slightly heavier flywheel. But it is still an improvement.

Only down side is that if you drift clutch kicking becomes fairly useless.

Hen

[stinger_007]

Has anyone here put a lighten flywheel on a gze?

I considered this when i did my clutch (3 months ago) but all my searching came up with similar results.

GZE with lightened flywheel = unstable idle.

Everyone reckoned it ran better with a heavier one.

Anyone tried?

[duste]

hello all

i had a ze in my sprinter, mircotech etc etc

i used a cusco flywheel in that, and the way it revved up like crazy

felt like it had more power and always seemed so keen to hit redline


i have a stock one now its turbo, (215mm fly now) but im going for a cusco one again!

highly recommended

[verm69]

i imagine a lighter flywheel will mean less torque but faster acceleration? am i right?

if so you wouldn't want to go too light as you'll loose the "ZE-ness" of your ZE :P

[Hen is a total nutcase]

No, the flywheel has zero effect on torque.

The engine will just rev more easily as there is less weight (or technically, rotational inertia) to spin up. Torque will not be affected at all.

Hen

[ke70dave]

i woudl have thought that lightened flywheel woudl effect its "cruisyness" of the engine

say driving along at 100km/h, come to a slight incline, stock flywheel engine will tend continue at constant speed, where as a lightened flywheel engine will drop in revs and require more acceleration to keep it goin at constant speed? since there is less rotating inertia?

is this relevant?

just what ive heard anyway!

[johl]

hmm... impretty sure teh main difference would be when the fly wheels has stopped or is changing speed quickly as there is less weight to move so it can do it faster so i suppose cruising up a hill or whatever wouldn't make too much difference... thats what makes sense in my head anyway

[roadsailing]

it will make a difference on hills, but so will the weight of your car, you wouldn;t stick 200KG of ballast in to make it "roll" up hills easier would you?

you will have to give it more juice earlier to go up a hill, but dont worry about it in terms of fuel consumption etc.

[chapl]

are all 4age flywheel bolts the same?

[Hen is a total nutcase]

Well I'd be very interested to see the results then.

[parrot]

What it will do is reduce momentum, so if you back off on the accelerator, the engine revs will drop quicker as there is less reciprocating mass, which is the same reason it will rev faster.

Can be a bit annoying for daily cruisy driving. I have enough trouble hitting the rev limiter as it is with 272 degree cams and a standard flywheel.

[Blown86]

<div class='quotetop'>QUOTE (Just Half Steppin @ Dec 14 2007, 11:20 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=452241)</div>
<div class='quotetop'>QUOTE (Hen is a total nutcase @ Dec 17 2007, 09:34 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=451753)
No, the flywheel has zero effect on torque.

The engine will just rev more easily as there is less weight (or technically, rotational inertia) to spin up. Torque will not be affected at all.

Hen[/b]

WRONG...

back to back testing has proven that a light weight flywheel DOES affect your torque.... lighter it is the more your torque is affected
[/b][/quote]

Another Ae86 owner able to defy the laws of physics!! :blink:

[Javal]

<div class='quotetop'>QUOTE (ke70dave @ Dec 13 2007, 04:28 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=451769)</div>
i woudl have thought that lightened flywheel woudl effect its "cruisyness" of the engine

say driving along at 100km/h, come to a slight incline, stock flywheel engine will tend continue at constant speed, where as a lightened flywheel engine will drop in revs and require more acceleration to keep it goin at constant speed? since there is less rotating inertia?

is this relevant?

just what ive heard anyway![/b]

This is correct, a heavier flywheel will tend to make the engine a bit more tractable, not smacking redlines and stalling all the time. This is great for stock cars / daily drivens, but it also hampers throttle response / how quickly the engine will 'pick up' to a degree.

So the car that will benefit most from a lighter flywheel is a hard tune N/A track car that revs 11tybillion, but there are many other suitable applications, and many others that are not so suitable.

It all comes down to parasitic drag.

It's basically the same as running 20 x 8 Chromies on your car, as opposed so some lightweight forged rims. It's going to take alot more effort to get them moving, but it's also going to take alot more to stop them.

I think i'm just repeating myself now.


<div class='quotetop'>QUOTE (Blown86 @ Dec 14 2007, 03:30 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=452327)</div>
<div class='quotetop'>QUOTE (Just Half Steppin @ Dec 14 2007, 11:20 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=452241)
<div class='quotetop'>QUOTE (Hen is a total nutcase @ Dec 17 2007, 09:34 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=451753)
No, the flywheel has zero effect on torque.

The engine will just rev more easily as there is less weight (or technically, rotational inertia) to spin up. Torque will not be affected at all.

Hen[/b]

WRONG...

back to back testing has proven that a light weight flywheel DOES affect your torque.... lighter it is the more your torque is affected
[/b][/quote]

Another Ae86 owner able to defy the laws of physics!! :blink:
[/b][/quote]

Dude this is JHS, he just defies laws in general :rolleyes:

[Blown86]

<div class='quotetop'>QUOTE (Just Half Steppin @ Dec 14 2007, 02:11 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=452331)</div>
<div class='quotetop'>QUOTE (Blown86 @ Dec 18 2007, 09:00 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=452327)
<div class='quotetop'>QUOTE (Just Half Steppin @ Dec 14 2007, 11:20 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=452241)
<div class='quotetop'>QUOTE (Hen is a total nutcase @ Dec 17 2007, 09:34 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=451753)
No, the flywheel has zero effect on torque.

The engine will just rev more easily as there is less weight (or technically, rotational inertia) to spin up. Torque will not be affected at all.

Hen[/b]

WRONG...

back to back testing has proven that a light weight flywheel DOES affect your torque.... lighter it is the more your torque is affected
[/b][/quote]

Another Ae86 owner able to defy the laws of physics!! :blink:
[/b][/quote]

explain....and im not an 86 owner
[/b][/quote]

Do some research...
Here's a hint:
http://en.wikipedia.org/wiki/Torque

A flywheel can only store energy, it DOES NOT and can not create or affect torque.

Please provide details of this "back to back testing".

[stefan]

from personal experience i was running a exedy 4.7kg flywheel was quite happy with it

reved smoother better pick up

alot more responsive

change down gears bit more hills driving mainly

didnt notice to much other than that

key thing is dont get anything to light or ull regret it

ie 3.6kg for street/hills well when you back off engine wont brake as much ie droping rpm quicker

but somthing from 4.1-5kg should be fine

[biggo]

heres one for you guys playing at home

how many of you know of a GZE conversion? Whats the eisest way to convert? 4age Flywheel of course. theres like 2kg difference right there and first hand reports ar so funny i killed the stock clutch before i even drove it out of the shed!

[li21]

How noticable is the acceleation increase with a lightened fly wheel on a modest setup ?

Whats the weight of a standard flywheel ?

[johl]

i got my 4.1 kg one in my car and it is noticeable. not so much with acceleration but with heel toeing and down shifting, mechanical decelleration etc it is very noticeable.

[4door]

4kg is good.

my trueno has 4kg flywheel and its amazingly better than stock flywheel.

driveability is not so bad. the revs drop very quick and is kind os shit for city driving, but u get smooth at it after a short time.

highly reccomended.

[4ac_mang]

http://www.pumaracing.co.uk/FLYWHEEL.htm

this guy seems to know his shit...

cheers
daniel

[Konakid]

^^Good article here is what i deduced from it that will answer most people questions.


To show the sort of numbers that a real car might have, I did some calculations based on a car with average gear ratios and tyre sizes - the table below shows the number of Kg of mass that would have to be removed from the chassis to equate to 1 Kg removed from the O/D of the flywheel at a radius of 5 inches.

GEAR MASS KG
1..............39
2..............12
3...............6
4...............4
5...............3

So in first and second gear this is a pretty important effect - I built an engine recently and managed to remove nearly 3 Kg from the outside of the standard flywheel - so that would be equivalent to lightening the car by over 100 Kg in 1st gear - not to be sneezed at in terms of acceleration from rest. With special steel or aluminium flywheels even more "moment of inertia" can be saved. The recent trend in racing engines to using very small and light paddle clutches and flywheels is therefore more effective in terms of the overall performance of the vehicle than it might first appear. Copyright David Baker and Puma Race Engines


Finally, you see some frankly unbelievable comments on car forums about lightened flywheels such as "they might make the car faster on the flat but it'll be slower up hills because that's where inertia helps you." Yeah right, heavy things go up hills so much better than light ones. That must be why all those trucks I overtake on the motorway come flying back past me up the next rise and then I overtake them again on the way down. A lightened flywheel has exactly the same effect as making the car lighter - no more no less. It will make the car faster everywhere - up hills, down hills, round my lady's chamber.

Also lightening the flywheel does NOT give the engine any more horsepower just like removing a sack of cement from the boot doesn't either. It simply leaves more of the horsepower available to accelerate the car because less is wasted in accelerating the flywheel.

Is there a downside? The only one of note is the idle quality. To get really smooth low rpm idle you need some flywheel mass to smooth the power pulses as each piston goes over TDC. This is more important the fewer cylinders the engine has. However in my experience it's simply not possible to lighten a standard cast iron flywheel so much that it greatly affects the idle quality. In fact some standard cars like Peugeots manage with very light flywheels anyway whereas others use a lot more mass most of which is unnecessary. For a track car none of this is even an issue though.

Any other upsides? One thing you'll find is the car will slow down much faster under engine braking because it doesn't have the flywheel inertia dragging it on. I much prefer a road car to be like this and you'll find you need to use the brakes less in normal driving.

Someone should add this to the FAQ.

[li21]

Great posts guys:)
That was helpful

Meathead #2's point about engine brakeing/ not having to use the brakes as much appeals to be, but wonder if I could put up with revs dropping too quickly in city driving like Kim says.