Date:         Fri, 29 Mar 2002 21:16:08 -0600
Reply-To:     Stan Wilder <wilden1@JUNO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Stan Wilder <wilden1@JUNO.COM>
Subject:      Re: On Longevity,
              Displacement,Efficiency and Technology in Conversions
Comments: To: keithahughes@QWEST.NET
Content-Type: text/plain; charset=us-ascii

I hesitate to set foot on the sacred ground of Waser Boxer territory but
isn't it a matter of selecting the engine that is the least problematic
of the selections.
If I were going to make a choice I'd absolutely go with an engine with a
cast iron block and an iron head as well. From my limited experience with
aluminum blocks and heads I'd tend to avoid them.
I can accept my Air Cooled Westy as is and live with the potential
problems but if I felt obligated to do a conversion it would be to a cast
iron engine.

Stan Wilder
83 Air Cooled Westfalia

On Fri, 29 Mar 2002 19:54:21 -0700 Nancy Eilers-Hughes
<keithahughes@QWEST.NET> writes:
> Kim Howe wrote:
>
> > On Tuesday, March 26, 2002, at 02:58 PM, Frank Grunthaner wrote:
> >
> > So, lifetime of any modern engine is directly related to the work
> you
> > require
> > that it generate during your ownership period. Period.
>
> Hmmmm....IMHO this is only accurate *if* each engine is run under
> optimal conditions. A hypothetical example:
>
> Let's say that both engine A and B operate at 70% efficiency
> (taking into account combustion efficiency, frictional losses,
> etc.), while operating at 5000 RPM, and 80% efficiency at 3500 RPM.
> The frictional losses, and concomitant frictional wear, would be
> much greater operating at 5000 RPM *with* a lower efficiency. Thus,
> engine A operating at 5000 RPM would be expected to produce, over
> its lifespan, significantly less 'work' than engine B running at
> 3000 RPM.
>
>
> > If I were to put an aircooled engine on a dyno and read off the
> torque,
> > I would be reading the torque including all cooling system losses.
> If I
> > were to do the same with a liquid cooled engine, I would be
> excluding
> > the drag introduced from the radiator,...
>
> And why do you think the radiator has drag? Think of the radiator
> as a perforated plate. Which has more aerodynamic drag, a 15 ft2
> solid plate, or a 15 ft2 perforated plate?
>
> >... and probably make sure I got my
> > readings before the fan cut in, so I excluded the alternator drag
> from
> > that too. Did you compensate for this at all? Do you know of any
> way to
> > calculate these losses? It would be interesting to see a
> comparison of
> > the total cooling system power requirements for air cooled and
> water
> > cooled engines. I remember seeing this done many years ago, and
> the air
> > cooled won hands down, which was behind my statement that
> aircooleds are
> > more efficient (ie air cooling wastes less energy).
>
> I've not seen the calculations you reference, but I fail to see how
> they could be accurate. A direct air cooled motor needs a large fan
> to move tons of air. This requires significant horsepower. On the
> water cooled side, you need only calculate the hydraulic losses
> (and minor pump frictional losses) and compare to the fan (were
> talking modern systems with electric radiator fans). While the
> hydraulic requirements *may* be higher, I would tend to doubt it.
> As stated above, the radiator (unless its incorporation directly
> results in a greater aerodynamic cross-sectional area) does not add
> drag.
>
>
> > If there were unreported losses in the water cooled that required
> say 5
> > ft.lb torque to compensate, that would mean as far as I can see
> that the
> > 2.0L a/c is about the same efficiency as the liquid cooleds of the
> same
> > vintage. This would be fun to evaluate.
> >
> > What do you think?
> >
> > Kim Howe
> > khowe@omninet.net.au
>
> Well, thermodynamic calculations aside, it requires only direct
> comparison of the 2.0l a/c with the 1.9L or 2.1L wbx, relative to
> fuel economy (in the same weight/configuration vehicle), to
> determine net efficiency ratios. With the 2.0l a/c getting 25%-35%
> lower mileage than the 2.1L wbx (under the same conditions, in
> every instance I've seen - including my own vehicles), the wbx is
> more efficient. What am I missing here?
>
> Keith Hughes
>

________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno.com/get/web/.