Sports: Re: [DucatiST] The New Ducati Engine!

Hopper,
Thanks man I get it now. I appreciate your patience with the
explanation. By swept area I meant the stroke length. Sorry for the
confusion but I'm always confused anyway according to SWMBO.

Gary '01 ST4 Gaston, OR

On 10/12/2011 2:27 PM, HOPPER ELDRIDGE wrote:
>
> Hi Gary,
> The bore/stroke ratio is mathematical formula of bore diameter divided
> by the length of the stroke.
> A 1:1 ratio would be a "square" engine (4 inch bore/4 inch stroke;
> 87mm bore /87mm stroke; etc).
> A 0.5:1 ratio would be under square (2 inch bore/4 inch stroke)
> A 2:1 ratio would be over square (8 inch bore/4 inch stroke)
> Another figure you'll see in conjunction with the "bore/stroke ratio"
> is the "rod/stroke ratio" which concerns the connecting rod length to
> stroke length. This takes into consideration the angle of the
> connecting rod to the wall of the bore.
> Where swept area comes into effect is the determining of the
> compression ratio:
> Swept bore volume + unswept bore volume, divided by unswept bore
> volume (9 cubic inches + 1 cubic inch) / 1 cubic inch = 10/1 = ten to
> one (10:1) compression ratio.
> There are some excellent books out there that give good descriptions
> of the different terms and how they baffect the design of an engine.
> I'm on the rig right now so don't have access to my library at home
> and even then I might not find the books...too much is still in boxes
> and the bookcases are packed in the garage.
> I got into all this back in my Norton racing and Pontiac GTO and Tans
> Am hotrodding days. get some books and read...really fascinating. With
> a little thought, I might remember some of the authors and books but
> the mind is a blank right now...OK, I'm 64..Ihave an excuse! <LOL>
>
>
> The Internal Combustion Engine in Theory and Practice, Volume 1:
> Thermodynamics, Fluid Flow, Performance
>
> by *Charles Fayette Taylor*
> <http://www.barnesandnoble.com/c/charles-fayette-taylor> Volunes I & II
> Four Stroke Tuning by A. Graham Bell
> Two Stroke Tuning by A. Graham Bell
> ...a few off the top of my head and a quicky search...
> Hopper
> --- On *Wed, 10/12/11, Gary L. Smith
> /<lgranch@laughing-gargoyle.com>/* wrote:
>
>
> From: Gary L. Smith <lgranch@laughing-gargoyle.com>
> Subject: Re: [DucatiST] The New Ducati Engine!
> To: st2_owners@yahoogroups.com
> Date: Wednesday, October 12, 2011, 12:51 PM
>
> OK Hopper et all,
> My understanding of "over square" is that the swept area of the
> piston is longer than the bore of the cylinder. An "under square"
> engine is one that has a bore larger than the swept area of the
> piston.
> Please correct me if I'm wrong and explain please.
>
> Thanks,
> Gary '01 ST4 Gaston, OR
>
> On 10/12/2011 7:07 AM, HOPPER ELDRIDGE wrote:
> >
> > Nick, go back to the information page and search through it.
> There are
> > a lot of tech pages in there. The engine is rotated a bit back for
> > more clearance to the front wheel but not as much as I figured it
> > would be from earlier information I had read...6 dgrees if I
> remember
> > correctly.
> > I agree with you too in that the bike is getting too complicated
> and
> > tech oriented. You'll shudder every time it rains or you give it a
> > bath. The newer bikes have too many problems as it is...now this
> one.
> > Love the HP readings but as you go to higher over square
> numbers, the
> > HP is shifted further up the RPM range. The power curves were
> nicely
> > linear though, not curvilinear. The basic design of a 90 degree
> V twin
> > will give better torque than other designs but the over square
> figures
> > will null that out to a point.
> > On my olde racing Norman White Norton Commando, we used a drag race
> > cam with the idea that a heavy flywheeled long stroke vertical twin
> > had enough torque in basic design but needed more HP. The bike did
> > well enough in BOTT that Tony Rutter approached Norm about
> racing it
> > in the '84 IOM pre-72 production class until that class was
> > eliminated...bummer!
> > Cheers...Hopper
> > --- On *Wed, 10/12/11, Nick Woods /<nickw@cooptel.net
> <http://us.mc807.mail.yahoo.com/mc/compose?to=nickw%40cooptel.net>>/*
> wrote:
> >
> >
> > From: Nick Woods <nickw@cooptel.net
> <http://us.mc807.mail.yahoo.com/mc/compose?to=nickw%40cooptel.net>>
> > Subject: Re: [DucatiST] The New Ducati Engine!
> > To: st2_owners@yahoogroups.com
> <http://us.mc807.mail.yahoo.com/mc/compose?to=st2_owners%40yahoogroups.com>
> > Date: Wednesday, October 12, 2011, 1:46 AM
> >
> >
> >
> > --- In st2_owners@yahoogroups.com
> <http://us.mc807.mail.yahoo.com/mc/compose?to=st2_owners%40yahoogroups.com>
> >
> <http://us.mc807.mail.yahoo.com/mc/compose?to=st2_owners%40yahoogroups.com>,
> > Jan Wysocki <st@...> wrote:
> > >
> > > I'm not entirely sure it's _my_ future.
> > >
> > > Ok, it's a desmo L-twin
> >
> > Yes, still a 90-degree motor, but did anyone else notice that the
> > engine on the stand seemed to be rotated backwards to give a
> > more-conventional vee configuration? I couldn't be sure of the
> > angle of the datum line provided by the script on the clutch case,
> > 'cos there were just too many atmospheric soft-focus close-ups....
> >
> > It's obvious that the only thrust of Ducati is top-end bhp, with
> > masses of high-tech gizmos to make the thing rideable at more
> > modest speeds, but I guess that's what sells bikes these days.
> > Probably it was always that way, and only the technology has
> changed.
> >
> > NickW, UK
> >
> >
>
>