karlak
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| posted on 26/6/11 at 03:42 PM |
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Flywheels and weight.
There seems to be such a variation in weight for Flywheels on the Duratec, so I was wondering what are the advantages and disadvantages of saving
weight.
Generally looking at
1) 3.1 Kilos
2) 4.7 Kilos
3) 6.0 Kilos
I think the Dual mass jobby that came out must have been the better part of 10 Kilos.
So the difference between the Dual Mass one at 10 Kilos and a 3.1 Kilos flywheel, how would it feel from behind the wheel on a standard setup engine
(with Tb's)
Cheers 
MK Indy - 2litre Duratec - Omex 600 - Jenvey throttle bodies - ETB DigiDash2
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omega0684
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| posted on 26/6/11 at 04:05 PM |
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my understanding is that the lighter the flywheel the less inertia is needed to get it to spin. as the flywheel can "spin up" quicker it
aids the engine revving quicker and ultimately an aid to better acceleration.
i would imagine that a 3kg flywheel will be made of ali and not steel, (mine is), & they cost the best part of about £300!
[Edited on 26/6/11 by omega0684]
I love Pinto's, even if i did get mine from P&O!
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craig1410
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| posted on 26/6/11 at 04:23 PM |
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If you have a radical camshaft in the engine then a heavier flywheel can help to keep it manageable at low revs otherwise it will be very lumpy and
prone to stalling. The heavier flywheel engine will be more tractable off the start line with less tendency to bog down.
Lighter flywheels have a couple of benefits, particularly in terms of responsiveness to throttle but this will only tend to be noticeable in lower
gears where the rate of increase of RPM is greatest (ie. 1st gear and maybe 2nd) but in higher gears the difference will be minor. The other benefit
is that the revs drop faster between gearchanges so the engine will be closer to the revs required for the next gear when it is engaged. This is
kinder to the synchro and will tend to give smoother changes.
To be honest, I don't think I'd spend a lot of money to go for a radical flywheel (either heavy or light). Best bet is to just tidy it up
as part of a balancing exercise and fit a good clutch and good quality pressure plate. Whatever you do, don't lighten to the point of risking
failure. Remember that some competition parts are expected to be replaced sooner than you might do with a road/track car.
HTH,
Craig.
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Paul TigerB6
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| posted on 26/6/11 at 04:29 PM |
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As above, lighter will be more responsive. For a road going car though, going too light will make the car too responsive and not so pleasant to drive.
That rotating mass dont forget keeps the engine spinning when you lift off and so taking too much mass away will mean the engine slows much
quicker.
Given the option, I think i'd stick to the 6kg option on a road car, and maybe the 4.7kg option on a trackday / road car. The 3kg option is
probably best suited to a race car. My Zetec car had one from Scholar Engines and that was around 5.5 - 6kg from memory (they do a Duratec one also)
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karlak
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| posted on 26/6/11 at 06:07 PM |
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Cheers guys. Appreciated
MK Indy - 2litre Duratec - Omex 600 - Jenvey throttle bodies - ETB DigiDash2
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coyoteboy
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| posted on 27/6/11 at 07:13 PM |
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6kg is standard on my 2 litre turbo tin top, but most people seem to cope fine with 3.5kg ones even though it's 4wd and tends to bog.
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