Lightened Flywheel

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Risocco
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Lightened Flywheel

Post by Risocco » Fri Apr 10, 2009 2:33 am

Evening gents. Has anybody done the above? Really like the idea of it just wondered what your thoughts were on the subject, or if anybody has any experience of the modification, that would be awesome too :chill:

Alex


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Re: Lightened Flywheel

Post by PeteGLi » Fri Apr 10, 2009 10:31 am

I don't think that just lightening the flywheel on its own will do much good. In fact, it may do more harm. Ideally, you should get the whole crankshaft and clutch assembly balanced so that the unit as a whole, rotates smoothly without vibration.



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Re: Lightened Flywheel

Post by Risocco » Fri Apr 10, 2009 2:33 pm

PeteGLi wrote:I don't think that just lightening the flywheel on its own will do much good. In fact, it may do more harm. Ideally, you should get the whole crankshaft and clutch assembly balanced so that the unit as a whole, rotates smoothly without vibration.
Hey Pete, cheers for that. I'm off to see a man about head-work so I'll have a word while I'm there. Have you ever had a flywheel lightened dude?

Alex


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Re: Lightened Flywheel

Post by the edmundator » Fri Apr 10, 2009 2:57 pm

I had one made for my racing car. In general a lightened flywheel will help with top end speed but reduce acceleration, at least from a standing start. I regularly made up several places off the grid simply because I was one of the few people without a lightened flywheel. Only problem was keeping them all. You definitely need to get it balanced.


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Re: Lightened Flywheel

Post by jrabarton » Fri Apr 10, 2009 3:53 pm

wow thats bizzare, i always thought a lightened fly wheel increased th acceleration and decreased the top end ... damm you forza motorsport you lied to me.



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Re: Lightened Flywheel

Post by Risocco » Fri Apr 10, 2009 5:49 pm

jrabarton wrote:wow thats bizzare, i always thought a lightened fly wheel increased th acceleration and decreased the top end ... damm you forza motorsport you lied to me.
Yeah me too :scratch: Seems odd, with less weight thought it would spin up faster thus increase acceleration. Oh well you live and learn.

Cheers Ed, this may well go on the back-burner in that case :good:

Alex


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Re: Lightened Flywheel

Post by scalainj » Fri Apr 10, 2009 6:51 pm

I've had on my road car for a long while now. Other than an utter pain when the engine is cold as the flywheel mass won't keep the engine spinning so it stalls its been fine.

Means for me a very quick throttle response so for example i can blip the throttle very quickly as the rev rise and fall is very quick indeed and bump starts can be done at walking pace or even a slight slope from a rolling start which balances out the stalling. Fine when run for 5 minutes or more

I didn't balance anything except the flywheel although i had an uprated clutch. Worked on the basis that VW had done that all for me when they made the bottom end. Seems to be ok. Probably best to follow the advice though.

Can't remember the exact weight left after work or what was taken off but it was many kgs of metal. I'm struggling to think how many years ago this was done. About 8 I reckon

Can't comment on whether its faster acclerating as i did major head work at the same time which increased redline and power so maybe it does accelerate slower than a normal one.

I think my top speed is less - just a guess as i've never tested it at all. Never ever. Not even once :chortle:

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Re: Lightened Flywheel

Post by the edmundator » Fri Apr 10, 2009 9:29 pm

I might be wrong about this... I would consult an expert. There might be one around here somewhere (I haven't noticed Doug T from the states pitching up yet...). I am not an expert. :?


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Re: Lightened Flywheel

Post by the edmundator » Fri Apr 10, 2009 9:37 pm

I think I might have been talking cobblers. Have a read of this:

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


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Re: Lightened Flywheel

Post by jrabarton » Sat Apr 11, 2009 8:31 am

Hallelujah

my faith in xbox racing games has been restored.



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Re: Lightened Flywheel

Post by PeteGLi » Sat Apr 11, 2009 1:03 pm

Risocco wrote:
PeteGLi wrote:I don't think that just lightening the flywheel on its own will do much good. In fact, it may do more harm. Ideally, you should get the whole crankshaft and clutch assembly balanced so that the unit as a whole, rotates smoothly without vibration.
Hey Pete, cheers for that. I'm off to see a man about head-work so I'll have a word while I'm there. Have you ever had a flywheel lightened dude?

Alex
Yes, the flywheel on my EG code 1.6 GLi engine was lightened when Brian Ricketts rebuilt the whole engine. Smoothest engine I've ever driven.



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Re: Lightened Flywheel

Post by Risocco » Sat Apr 11, 2009 2:25 pm

PeteGLi wrote:
Risocco wrote:
PeteGLi wrote:I don't think that just lightening the flywheel on its own will do much good. In fact, it may do more harm. Ideally, you should get the whole crankshaft and clutch assembly balanced so that the unit as a whole, rotates smoothly without vibration.
Hey Pete, cheers for that. I'm off to see a man about head-work so I'll have a word while I'm there. Have you ever had a flywheel lightened dude?

Alex
Yes, the flywheel on my EG code 1.6 GLi engine was lightened when Brian Ricketts rebuilt the whole engine. Smoothest engine I've ever driven.
OK no worries, cheers for the input matey, think I'll leave this a bit and get the crank done to match it.

Just one more question, did you feel much improvement with the lightened flywheel?

Alex


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Re: Lightened Flywheel

Post by MikeH » Thu Apr 16, 2009 12:23 pm

An 020 flywheel weighs about 5kg as standard, and you can get them down to about 3kg.

This helps acceleration in 1st and 2nd gear, but isn't really noticeable above that. David Vizard did a really good explanation of the effects of flywheel lightening on performance in his 'How to Modify Your Mini' book, back in the '70s.

Based on mini gearing ratios, he found that removing 1kg from the flywheel was the equivalent of removing about 10kg from the weight of the car in first gear, then progressively less according to gear ratios, as you go up the 'box. That calculation won't be right for a VW, but the principle is the same.

The downside is that you'll find it easier to stall the car when moving off, you might need to adjust tickover, and might lose some idle stability, based on my experiences with a Mk2 Golf 2.0 16v.

If the flywheel is balanced to itself, you won't have an issue with vibration. A decent machine shop will balance the fly to a tighter spec than the factory did, and the factory wouldn't have balanced the flywheel and clutch together (or at least, none of the several engine factories I've worked in ever did it). However, on a competition car, balancing with the rest of the crank assembly will probably prolong the life of your engine at high RPM.


It's marginal whether it's worth it on a road car. If you're trackdaying or racing, then it's more of a benefit.


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Re: Lightened Flywheel

Post by Risocco » Thu Apr 16, 2009 2:59 pm

Hi MikeH, so you wouldn't recomend it for a daily driver dude? Cheers for the input tho mate :good:

Alex


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Re: Lightened Flywheel

Post by MikeH » Fri Apr 17, 2009 1:16 pm

It's marginal on a daily - handy for the traffic light grand prix, but not much use otherwise!

Having said that, I'm putting one on mine, when I change the clutch, because I've got one spare.


1992 Scala ABF - SOLD
1989 Scala track toy. Dormant
1986 GTX - Lunar mileage but still a good un
Mk1 Classic Touring Car Project...slowly does it
1984 1.6 GT Project. 69k In progress
1.6GL. 2 Owners, 60k. SOLD
1.6 GL - 100k miles -Back on the road!