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Date:         Sat, 28 Jul 2007 16:41:53 -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)
Comments: To: Jim Akiba <syncrolist@bostig.com>
In-Reply-To:  <ac1f198b0707281516p1ff5d358x8beb040e49ed6d91@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Jim, I was trying to find the dyno results on your site and failed. Is it just me or are they cunningly hidden?

On 7/28/07, Jim Akiba <syncrolist@bostig.com> wrote: > > it's interesting because the undercladding for syncro that we're also > looking at would apparently also help in this regard. Lot's of the > off-road > guys are actually using large sheets of teflon attached to support > structures as skid plating these days. Corrosion proof, very tough, light, > and take impact well if properly supported. Also very easy to CNC route. > > The water tank and scale model would be interesting to play with, I'm > quite > excited to try the solid model in CFD software though, as with the right > setup it should be pretty accurate. > > Jim Akiba > > > On 7/28/07, Alistair Bell <albell@uvic.ca> wrote: > > > > Finally a worthwhile discussion :) > > > > Frank, hats off on your undercarriage work. Definitely a do-able > > solution. The rear low press problem is harder. Instead of trying to > > fair that area how about an attempt to "curve the flow" in there? > > While not nearly as effective it may be more practicable. I'm > > thinking of wings/winglets on top and sides. We've seen some full > > width top wings and the smaller deflectors (linked posted on list a > > few years ago, NZ? firm making small deflectors). > > > > A splitter also may be effective. Flat panel perpendicular to rear > > hatch, length to be determined. > > > > I have a spare small water tunnel that my revell Vanagon model would > > fit in. Would be useful for flow visualisation and perhaps some > > scaled drag values. > > > > > > Alistair > > > > > > On 28-Jul-07, at 1:01 PM, Frank Grunthaner 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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