Date: Sat, 28 Jul 2007 13:59:46 -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: <cad.1637ae1d.33dcfa85@aol.com>
Content-Type: text/plain; charset=ISO-8859-1
Nice work Frank - its a pleasure to listen to your reasoned and
knowledgeable lectures. :-)
On 7/28/07, Frank Grunthaner <FrankGRUN@aol.com> wrote:
>
> In a message dated 7/28/07 11:05:21 AM, syncrolist@bostig.com writes:
>
>
> > 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
> >
> >
> > Jim,
>
> Egad a reply to one of my rants! Exciting! I fully agree that results from
> the same dyno with the same operator seriously increase the quality of the
> data
> but more importantly the reality factor inherent in its comparative
> interpretation. For some time my son and I were developing a Solidworks
> based model of
> the Westfalia to tighten up the drag issues. Our power numbers come to
> second
> difference velocity curves taken at the Pomona International Dragway (when
> unoccupied by paying nutsos). We were also looking at FemLab for a far
> more
> detailed treatment.
>
> In the course of these experiments, two areas showed enough promise to
> warrant some measurements. We looked at the rear drag profile and
> undercarriage
> sealing. For the rear drag issue, we modeled pressure zone profiles and
> put
> together three plastic hemi-balloons and taped then to the rear. I have to
> go back
> to my notes at the time but we reduced drag by 12 to 18%. In one test, the
> number was 33% but it couldn't be duplicated. (In the spirit of some
> tuners, I
> should have used this for an SAE paper). The upshot of this was that I got
> pulled
> over (we were testing at night on the Palmdale highway) by the CHP and got
> ticketed for occluded rear vision. Went to the court to fight the ticket.
> Had a
> full sheaf of papers. The judge listened attentively (!). He remarked that
> when younger he had had a bay window bus that just blew all over the road
> and
> asked if such mods would have any effect on stability. I offered that it
> was in
> the relm of possibility. I them looked around the courtroom to see blank
> stares
> for a mass of humanity that that must have thought I came from area 51.
> Finally the judge stopped the discussion, announced that this was the
> singularly
> most unusual anti-ticket response he ever heard, congratulated me for
> originality and dismissed the ticket with a warning about frightening
> other drivers at
> night.
>
> The point here relates to the fundamental flaw. The rear balloon worked,
> we
> had an idea for speed related inflation, etc, etc, but no answer for rear
> vision. Practicality --- zip, but fun.
>
> The second idea worked well and is a real solution. The open underside of
> the
> vanagon is a real drag component. We got a set of thin 0.0625 inch Al
> sheet
> stock and enclosed (frame rail to frame rail) and basically covered the
> underside from the front to the transmission. We added louvered slots for
> the
> radiator air flow, left the spare tire cover operable and stayed away from
> suspension
> components. Big decrease in drag - minimum 8% max 15%. 15% came when we
> added
> the Diesel sound box cover. Serviceability was a problem. The system has
> been
> removed as I complete the front to back dual muffler system for the TDi
> and
> the diesel fired heater. No temperature measurements, but we provide for
> air
> inlets at front by gas tank and at egress at the rear. Work in progress.
>
> 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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