Date: Sat, 28 Jul 2007 11:42:46 -0700
Reply-To: Jake de Villiers <crescentbeachguitar@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jake de Villiers <crescentbeachguitar@GMAIL.COM>
Subject: Re: Power output of actual vans? (long)
In-Reply-To: <ac1f198b0707281105x616694a4o2294544f20f46a82@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Great thinking as always Jim. Have you seen the pix of the fabric 'skirt'
built by some folks in Colorado to give them more length and way better
MPG?
I'll see if I still have their web address; I lost some data when my hard
drive pooched.
On 7/28/07, Jim Akiba <syncrolist@bostig.com> wrote:
>
> Ha I liked your reply Frank. Excellent. We have multiple dyno charts all
> taken from the same chassis dyno for a vanaru 2.2, tiico HO, 2 wbxers, 4
> different zetecs, 1 supercharged zetec, and coming soon e85 naturally
> aspirated zetec, and e85 supercharged zetec.. as well as the upcoming
> turbo
> kit(the entire exhaust tract is now complete) Having all this info from
> the
> same dyno is quite nice, and really the only way to do it. As Mark points
> out, it is the "complete" inforamtion that is really required. BTW Frank,
> Clint(a listmemeber and solidworks guru) is helping us model the vanagon
> so
> we can put it into a CFD virtual wind tunnel... my intention is to build a
> collaspable colluder cone (see through on top) to see how much fuel
> efficiency we can gain at cruise with a simple strap on cone of reasonable
> size that is easy to produce and inexpensive. I think given the low
> pressure
> area we always drag around behind us, it may be a substantial improvement.
>
> Jim Akiba
>
>
>
> On 7/28/07, Frank Grunthaner <FrankGRUN@aol.com> wrote:
> >
> > In the archives, I have posted a number of analyses of torque and brake
> > specific fuel consumption as a function of net gearing to the road for
> VW
> > and Audi
> > I4, WBX and Subaru engines. These were based on actual measured output
> > curves
> > coming down to torque at the tire patch. I attempted to show the impact
> of
> > drag (aero and mechanical) as well as mass for the Westfalia and its
> > impact on
> > residual thrust available for acceleration and hill climbing. I
> attempted
> > to
> > show that many of the accepted wisdom forms related to gearing,
> > performance and
> > fuel economy were system issues that had to take into account the
> inherent
> > pumping efficiency of the engine (what usage range was it designed and
> > then tuned
> > for). The generally accepted geriatric nonsense that regearing for lower
> > cruising rpm at higher load factors would deliver better fuel economy
> > seems to
> > continue nonetheless.
> >
> > I did not treat the Zetec I4 at the time as it was not then a viable
> > solution. I am preparing a similar dissertation on the various TDi
> engines
> > and their
> > tuning modifications complete with extensive design material from VW and
> > Audi
> > and results from those US and Euro tuners I respect. I'll post these
> > analyses
> > within the next month, schedule permitting. My previous postings on the
> > subject
> > (ignored by most amateur conversion engineers in the group) can be found
> > by
> > searching the archives under my email address: FrankGRUN@AOL.com.
> >
> > But as Mark and others have reiterated, its real torque or thrust at the
> > wheels. Or perhaps slightly differently performance is given by the
> excess
> > thrust
> > available from the engine at any given rpm after delivering the work
> > needed to
> > maintain the vehicle in its present state. The fuel economy for a given
> > engine class (diesel or gasoline) depends mostly on the neural damage of
> > the driver
> > but secondarily on the internal resonant flow dynamics of the intake
> > system,
> > the combustion chamber design, the valve profile dynamics and the
> exhaust
> > resonances. The Carnot cycle is alive and well so in all cases a
> > turbocharged
> > engine can deliver better BSFC for a specific power demand than any NA
> > engine.
> > Again professional engine design is the key. Anecdotal results such as
> 35
> > mpg at
> > 80 mph in a fully loaded Westfalia while achieving 0-60 mph in less than
> > 10
> > seconds belong in the Twilight zone of supersaturated testosterone
> > generators.
> >
> > Frank Grunthaner
> >
> >
> > **************************************
> > Get a sneak peek of
> > the all-new AOL at http://discover.aol.com/memed/aolcom30tour
> >
>
--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
www.crescentbeachguitar.com
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