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Discussion Starter #1 (Edited)
Just found this article. Why not have an aftermarket company market such a wing?

http://www.greencarcongress.com/2004/12/on_the_wings_of.html

On the Wings of a Beetle: ~60+ mpg
14 December 2004

Ernie Rogers, an aerospace engineer, set out on a mission “to promote fuel conservation and reduce greenhouse gas emissions by researching, developing and commercializing novel technologies that simply and cost-effectively improve the efficiency of cars and trucks.”

One of those technologies or approaches is the addition of a simple aerodynamic drag reducer. Adding such a device (picture to the right) and slightly oversized, low rolling-resistance Michelin Energy MXV4 S8 tires to his 2003 VW Beetle TDI diesel resulted in an average 58.8 mpg in extended, high-speed highway driving. The EPA rates the diesel Beetle at 49 mpg highway. Here are his latest specific results:

Fuel Consumption w/ Drag Reducer and Low Resistance Tires
Date Miles Traveled Fuel (gal) MPG l/100 km
2 Nov 04 797.6 13.71 58.2 4.04
11 Nov 04 793 13.37 59.3 3.96
24 Nov 04 786.7 13.45 58.5 4.02
8 Dec 04 792.5 13.37 59.3 3.96
Average 58.8 4.00
 

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Discussion Starter #2 (Edited)
Here's a report of a 62 mpg drive to Alaska by the same fellow on his 2003 NB TDI. Notice how fuel quality/formula, tire pressure, and especially speed are significant factors for hwy mpg. He was using Cruise Control on the hwy at 62 mph.

http://www.drive55.org/pn/modules.php?op=modload&name=News&file=article&sid=45&mode=thread&order=0&thold=0

2003 VW Beetle on biodiesel to Alaska by Ernie Rogers
Posted by: Admin on Wednesday, July 28, 2004 - 11:28 AM

"Trip speed was carefully controlled to 100 km, or 62 miles, per hour."

I just completed a trip to Alaska with my grandson, in a 2003 Beetle TDI diesel. We achieved a fuel efficiency of about 115 person-miles per gallon of fuel for the trip. I think that would compare favorably with competing transportation methods. We had intended to biodiesel (B20) for the entire trip. In the end, we o nly had biodiesel for o ne tank, obtained at West Yellowstone.

On the return trip, I made an interesting discovery for petrodiesel--

1. Fuel purchased last Friday in Edmonton (Shell) gave 56 miles per gallon.
2. BUT fuel purchased Saturday in Idaho Falls (Phillips, from Utah refinery) gave 63 miles per gallon.

The difference here is much larger than the expected variation due to systematic or random errors.The fuel from the more southern station and refinery gives 12% more mileage than the more northern fuel.Travel conditions were about as much alike as possible, good highways and nearly perfect, windless weather. I think the fuel performance difference is traceable to differences in fuel composition, and resulting difference in energy density. This situation closely parallels differences seen between summer and winter diesel formulas. I haven't called the fuel producers, but I suspect that the northern fuel has a higher hydrogen content, in other words, they blended in some #1 diesel. This lower fuel performance was seen over all the fuel purchased in Alaska and northwest Canada. The ASTM spec for diesel fuel probably has a full explanation. I probably should dig the spec out of my files and see what it says about this.

By the way, pretty good fuel economy, wouldn't you say? (Trip speed was carefully controlled to 100 km, or 62 miles, per hour.) And, air emissions are very low (based upon my nose measurement) since I had the EGR turned all the way down (to the legal limit).

Changes I have made to my car:
1. Made a drag-reducing "wing". I can send a picture. It increases mileage by 3 mpg.
2. Reset the EGR code. See http://www.tdiclub.com/, FAQs for instructions. Effect unknown.
3. Raised tire pressure to about 33 cold, 38 hot. Probably adds another 1 mpg.
4. I usually drive o n the highway at a steady (on cruise control) 62 to 65 miles per hour. This is the most important "change." Adjusting speed gives the following results:
Summer mileage, no wing, constant speed o n I-80 Tooele to Wendover, UT, Flying J fuel, 2003 VW New Beetle TDI diesel.

60 mph 58.2 mpg
65 mph 57.1 mpg
70 mph 51.1 mpg
75 mph 46.4 mpg
80 mph 42.7 mpg


Numbers in the table are uncorrected for gauge errors. Miles traveled per test, about 197 miles, was read from the trip meter; this reads about 1% low. Speed is the speedometer reading, which is about 3% high. Tank is filled just before and after test run, which takes about three hours. Tank vent valve is held open during filling, and I fill to about o ne inch from top. Fuel measurements are thought to be repeatable to 0.05 gallon (no temperature correction). Results are collected o n days with no wind or rain.You can see that, if the latest result holds true, then Phillips summer diesel is outperforming Flying J diesel by about 2 mpg.Well, now that I have things measured for petrodiesel, I guess I should do similar stuff for biodiesel.

Ernie Rogers
:)
 

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Discussion Starter #3 (Edited)

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Not to dispute what this guy has tracked, but that wing would effect your driving different for the different situations you would drive in. For instance...at 60 mph that wing will effect your drag differently than at 30 mph. In fact it might negatively effect your drag based on wind and a whole lot of things. Does the Beetle have a poor drag coefficient (Yes) but you would need to drastically alter the backend like one of those tear drop looking things to really make a difference.

Ernie drives very slow on the highway compared to most of us and he has a much different route (lots of flat straight highway) than most of us. Most of us could achieve his numbers with the right air pressure in our tires and a similar route and speed.

Additionally, not to discredit what Ernie has done, but he hasn't tested it in a wind tunnel. He estimates his drag reduction based on road tests in a semi-controlled environment (same road, same car, same tire pressure, approximately the same weather). There are many variables he can't account for in that testing and I remain skeptical until some more accurate testing has been done.

Typically it would take a more dramatic design change than that wing to change the overall drag. Additionally, there are plenty more factors effecting Ernie's fuel mileage. Adding this wing will not get you 60 mpg.
 

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Excellent results. Too bad the thing is butt ugly, and not apparently amenable to beautification. If we had wanted an ugly car, we could have bought a Golf TDI.

So now, the question I'll have to ponder: how much fuel efficiency am I willing to sacrifice for quirky looks? That's going to be a tough one.
 

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In my neighborhood something like that would result in every youngblood I came across with phart pipes and a spoiler wanting to drag race me at the light.
 

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I always find it interesting when someone says something like "to reduce greenhouse gases" and then embarks on a long trip. If he were THAT concerned about it he'd leave the car parked or ride a bike.
With that said I wonder if his decrease is fuel mileage was ambient temperature related. He didn't mention the temperature. I'm assuming it was colder up North. Temps make a big difference in diesel mileage.
Pretty cool stuff really but it IS ugly. I wonder how it handles cross-winds !
 

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My only question would be: are these numbers for real?

Summer mileage, no wing, constant speed o n I-80
60 mph 58.2 mpg
65 mph 57.1 mpg
70 mph 51.1 mpg
75 mph 46.4 mpg
80 mph 42.7 mpg

On streight and level interstates here in Cali, at the same speeds, the milage is a lot less. As CARBinated fuel will give fewer miles per gallon than fuel from outside of Cali.
At a constant 60 MPH, the best fuel milage eeked out was just shy of 50 mpg. Darn near got run over by everyone else wanting to go faster while trying out the econo run.
Is fuel from outside Cali that much better for fuel milage? I'd think that maybe 8% to 10% at most.

If true, then the ULSD fuel due out soon is going to ba a big shock to the drivers outside of Cali as it will deliver fewer miles per gallon than the current CARBinated fuel.
 

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Dorado said:
I missed this news last September, the same guy won the fuel economy competition at the 2005 TDI Fest:

http://www.drive55.org/pn/modules.php?op=modload&name=News&file=article&sid=64&mode=thread&order=0&thold=0
It's not news to me. For TDIfest, I went from Minneapolis to my hotel in Fort Atkinson, WI, going an indicated 65 on I-94 and got 55 mpg. That day I was running the OEM tires, the Elf 506.01, and corrected for odometer error.

In 2006, some of us are planning a run from Oakdale, MN to King of Prussia for the Fest - with a fuel efficiency competition subject to an effective minimum speed.

In fact, I posted an entire route here.
 
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