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Lightened Flywheels

Subject: Lightened Flywheels
From: jdbubb@ix.netcom.com (Dan Bubb)
Date: Thu, 28 Mar 2002 07:17:44 -0500
References: <20020327205907.16811.qmail@web10301.mail.yahoo.com> <3CA2145A.1020506@qwest.net>
If an engine has a very heavy flywheel it will have a large effect on
the speed of the car if the revs are not matched correctly since a lot
of energy is transfered from the car to the flywheel to speed up the
flywheel. With a light flywheel litte energy is required to speed it up,
so a lighter flywheel requires LESS precision in matching revs to shift
smoothly.
Dan

Mike Blain wrote:
>=20
> I believe that the lighter the flywheel the more you'll have to match
> RPMs to downshift- case and point being my 928 which has the lightest
> flywheel ive ever seen (it's a thin piece of tin). I have to gas it and
> match RPMs  (called heel/toeing) to drop a gear smoothly for
> acceleration. There is little effect from engine braking.
>=20
> Ron Pieper wrote:
>=20
> > I disagree...engine braking would be hindered by NOT having the
> > flywheel helping to maintain the existing RPM.  Having the engine
> > quickly drop revs *decreases* the effect of engine braking - it would
> > provide little resistance.  Example:  imagine a massive flywheel - 5'
> > diameter - ...if you have a given car speed, and drop a gear and
> > release the clutch, your engine braking effects will be significant
> > since the engine *won't* easily change revs to match the car/gear.  I=
f
> > you have a tiny flywheel, the engine RPM can more easily change,
> > reducing the effects of the engine's braking on car speed.  It's not
> > the speed of the engine that provides braking, it's the engine's
> > resistance to a change in speed (it's rotating mass, of which the
> > flywheel is a part).
> >
> > Now, OTOH, engine braking is not something I do or recommend...I have=
 a
> > tool for that, it's the brakes!
> >
> > Ron
> >
> > --- Dan Bubb <jdbubb@ix.netcom.com> wrote:
> >
> >>Wait a minute! Why would there be less engine braking?
> >>The braking effect of the engine is not changed by lightening the
> >>flywheel (since engine braking is a function of the engine trying to
> >>pump air against a closed throttle) and the reduced inertia means the
> >>engine revs will drop faster. As a matter of fact with the reduced
> >>inertia there is less mass holding the engine revs up so the net
> >>effect
> >>is slightly (very slightly) MORE engine braking.
> >>Dan
> >>
> >>Ken Bates wrote:
> >>
> >>>Oooohh,  That is a good pont.  I would not have thought of that.
> >>>
> >>This mod
> >>
> >>>would be on my "list" the next time I do a clutch.    I am a
> >>>
> >>"downshifter"
> >>
> >>>when i am driving hard and this diminished effect would be missed.
> >>>
> >>Thank
> >>
> >>>you for bringing that up.
> >>>Ken
> >>>'79 Scirocco 16v project "McFly"
> >>>'86 16v (parts car)
> >>>VORTEX:  "Indiana Red"
> >>>
> >>>----- Original Message -----
> >>>From: "Robert Piwonka" <tpiwonka@TTACS.TTU.EDU>
> >>>To: "Scirocco" <scirocco-l@scirocco.org>
> >>>Sent: Monday, March 25, 2002 2:32 PM
> >>>Subject: RE: Lightened Flywheels
> >>>
> >>>
> >>>>on stock cams I noticed no difference in idle characteristics
> >>>>
> >>when I had
> >>
> >>>the
> >>>
> >>>>Velocity lightened flywheel.  However donwshifts have less effect
> >>>>
> >>ie. less
> >>
> >>>>engine breaking and the car reved(sp) like a motorcycle ;)
> >>>>
> >>>>Robert Piwonka
> >>>>86 16V
> >>>>
> >>>>-----Original Message-----
> >>>>From: scirocco-l-admin@scirocco.org
> >>>>[mailto:scirocco-l-admin@scirocco.org]On Behalf Of Allyn
> >>>>Sent: Monday, March 25, 2002 2:18 PM
> >>>>To: Euroroc II; Brian Wagner; Scirocco-l@scirocco.org
> >>>>Subject: Re: Lightened Flywheels
> >>>>
> >>>>
> >>>>Heavy - slower acceleration, smooth idle
> >>>>Light - lumpy idle, at an extreme you may have to raise idle
> >>>>
> >>speed to
> >>
> >>>>maintain idle without stall
> >>>>Al
> >>>>
> >>>>----- Original Message -----
> >>>>From: "Euroroc II" <flaatr@yahoo.com>
> >>>>To: "Brian Wagner" <scirocco_88_16v@hotmail.com>;
> >>>>
> >>><Scirocco-l@scirocco.org>
> >>>
> >>>>Sent: Monday, March 25, 2002 2:12 PM
> >>>>Subject: Re: Lightened Flywheels
> >>>>
> >>>>
> >>>>
> >>>>>So anyone want to clear up the pros and cons of lightening the
> >>>>>
> >>fly
> >>
> >>>wheel?
> >>>
> >>>>>I've got a good idea of the advantages and disadvantages but
> >>>>>
> >>I'd like to
> >>
> >>>>>get them confirmed.
> >>>>>
> >>>>>-Raffi
> >>>>>
> >>>>>
> >>>>>At 12:07 PM 3/25/02 -0600, you wrote:
> >>>>>
> >>>>>>6 is extremely light, most of the lightened flywheels you buy
> >>>>>>
> >>are
> >>
> >>>8.3lbs
> >>>
> >>>>>>that might be a better bet.
> >>>>>>
> >>>>>>Brian
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>From: "Sal Guzzo" <pellom@YorkU.CA>
> >>>>>>>To: "Scirocco" <scirocco-l@scirocco.org>
> >>>>>>>Subject: Lightened Flywheels
> >>>>>>>Date: Mon, 25 Mar 2002 12:20:57 -0800
> >>>>>>>
> >>>>>>>Hi all,
> >>>>>>>
> >>>>>>>I wanna lighten my flywheel but I'm not sure how much to take
> >>>>>>>
> >>off.
> >>
> >>>It's
> >>>
> >>>>a
> >>>>
> >>>>>>>210mm flywheel for an 8V.  I think that it weighs about 12
> >>>>>>>
> >>pounds now
> >>
> >>>>and I
> >>>>
> >>>>>>>was thinking of having it reduced to about 6 pounds.  Is that
> >>>>>>>
> >>kewl?
> >>
> >>>>>>>TIA
> >>>>>>>
> >>>>>>>Sal
> >>>>>>>
> >>>>>>>
> >>>>>>>_______________________________________________
> >>>>>>>Scirocco-l mailing list
> >>>>>>>Scirocco-l@scirocco.org
> >>>>>>>http://neubayern.net/mailman/listinfo/scirocco-l
> >>>>>>>
> >>>>>>
> >>>_________________________________________________________________
> >>>
> >>>>>>Chat with friends online, try MSN Messenger:
> >>>>>>
> >>http://messenger.msn.com
> >>
> >>>>>>
> >>>>>>_______________________________________________
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> >>>>>>Scirocco-l@scirocco.org
> >>>>>>http://neubayern.net/mailman/listinfo/scirocco-l
> >>>>>>
> >>>>>
> >>>>>_________________________________________________________
> >>>>>Do You Yahoo!?
> >>>>>Get your free @yahoo.com address at http://mail.yahoo.com
> >>>>>
> >>>>>
> >>>>>_______________________________________________
> >>>>>Scirocco-l mailing list
> >>>>>Scirocco-l@scirocco.org
> >>>>>http://neubayern.net/mailman/listinfo/scirocco-l
> >>>>>
> >>>>
> >>>>_______________________________________________
> >>>>Scirocco-l mailing list
> >>>>Scirocco-l@scirocco.org
> >>>>http://neubayern.net/mailman/listinfo/scirocco-l
> >>>>
> >>>>
> >>>>_______________________________________________
> >>>>Scirocco-l mailing list
> >>>>Scirocco-l@scirocco.org
> >>>>http://neubayern.net/mailman/listinfo/scirocco-l
> >>>>
> >>>>
> >>>_______________________________________________
> >>>Scirocco-l mailing list
> >>>Scirocco-l@scirocco.org
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> >>>
> >>_______________________________________________
> >>Scirocco-l mailing list
> >>Scirocco-l@scirocco.org
> >>http://neubayern.net/mailman/listinfo/scirocco-l
> >>
> >
> >
> > =3D=3D=3D=3D=3D
> > Cheapass Ron
> > "Victor" '87 16V Scirocco
> > "Teufelhasen" '93 Cabby <-For sale
> >
> > If it ain't foggy, TURN OFF YOUR FOG LIGHTS.
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Yahoo! Movies - coverage of the 74th Academy Awards=AE
> > http://movies.yahoo.com/
> >
> > _______________________________________________
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> > Scirocco-l@scirocco.org
> > http://neubayern.net/mailman/listinfo/scirocco-l
> >
> >
> >
>=20
> _______________________________________________
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> Scirocco-l@scirocco.org
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Follow-Ups:
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  - From: rept@qwest.net (Mike Blain)
References:
- Lightened Flywheels
  - From: rapieper@yahoo.com (Ron Pieper)
- Lightened Flywheels
  - From: rept@qwest.net (Mike Blain)
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