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Steelhead
Samba Member
Joined: February 25, 2007
Posts: 1791
Location: Kentfield, CA
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 Posted: Mon Feb 09, 2009 8:14 pm Post subject: |
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| Andrew A. Libby wrote: |
I've been curious how much of a difference mud flaps make.
Andrew |
and while we're wondering...what about syncro height vs. carat height?
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'77 Bay Window / '89 Caratsburg (aka. the Stormtrooper) |
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pushkick
Samba Member
Joined: August 09, 2007
Posts: 1366
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| Posted: Mon Feb 09, 2009 9:06 pm Post subject: air flow |
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are you talking about covering the roof rack/ storage area above the front of the van?
what about front bumper storage rack with a wind foil? would this help at
highway speeds and for long trips? |
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Rhinoculips
Samba Member
Joined: August 08, 2005
Posts: 918
Location: Keystone, Colorado
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| Posted: Mon Feb 09, 2009 9:25 pm Post subject: |
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Back to the original question....
If you look at the aerodynamic image given earlier, look at the orange Westy. Notice smoke and the big gap over the rear of the van. Then look at the non-Westy. Big difference. On the Westy, the rear half of the van above the poptop has no wind force in the area where the original poster has his box mounted. The wind is pushed up higher, over the box. It is almost a vacuum in this area. Thus, I don't think the box would effect the MPG's on a Westy like it would on a non-Westy.
Doesn't matter either way. Our vans, no matter how you look at them, are as aerodynamic as a barn.
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sc-surfer
Samba Member
Joined: May 16, 2005
Posts: 865
Location: Santa Cruz, CA
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| Posted: Mon Feb 09, 2009 10:10 pm Post subject: |
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Fully loaded, 2 passengers, Thule box on top, well tuned stock 2.1l, speed at 55-65, up/down hill and over dale, 21 mpg. Can't imagine my box costing 5 mpg. I know I wouldn't get 26 mpg without it! My guess is that the newer aero boxes don't change mpg much on a Vanagon. Might on a much smaller car as a factor of percentage though.
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'89 Syncro Westy
Catalog of Vans at SDM 2010
Westfalia, Syncro & Tristar Reproduction decals here.
* * * Coming Soon: Washable seat covers for westy bench seat...keep the pets off the upholstery! * * * |
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targis58
Samba Member
Joined: July 11, 2006
Posts: 539
Location: sunnyvale,ca
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| Posted: Mon Feb 09, 2009 11:10 pm Post subject: Re: air flow |
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[quote="pushkick"]
what about front bumper storage rack with a wind foil?
 what is it? what is available?
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90 westy 2wd w/ TBD |
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RoryGirl
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Joined: October 14, 2016
Posts: 784
Location: WestWorld Nanaimo BC
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Steve M.
Samba Member
Joined: July 30, 2013
Posts: 6829
Location: Fort Lauderdale, Fl.
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| Posted: Wed Mar 25, 2020 6:57 pm Post subject: Re: roof cargo box vs. MPG |
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Yes, but now it is an aerodynamic lifting body. So in theory, the faster you go the less grip the tires have.
Doubt if he'll reach take off speed, but the way some people drive a sudden move off the straight line might be a surprise. Most likely not!
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There are seven days in a week. Someday is not one of them. |
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pdm777
Samba Member
Joined: August 06, 2012
Posts: 348
Location: Clovis, CA
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| Posted: Wed Mar 25, 2020 9:56 pm Post subject: Re: roof cargo box vs. MPG |
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After looking at the wind tunnel pics,
I moved my box as far back as possible.
and as low as possible. Aero
This also greatly improves effort to pop the top,
as the more weight rearward, the easier to pop the top.
Those with racks sticking way up in the airstream, boxes up high, ==== WWII German Stuka Dive Bomber air brakes, they are designed for max drag, and a set of triple wide ass pipe Yakima racks with a cargo box ain't far behind.
Next project is an airdam, with adjustment for raising and lowering.
First photo is before and after, lowering and moving as far back as possible.
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1990 Westy Full Camper |
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Steve M.
Samba Member
Joined: July 30, 2013
Posts: 6829
Location: Fort Lauderdale, Fl.
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| Posted: Thu Mar 26, 2020 5:06 am Post subject: Re: roof cargo box vs. MPG |
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Installing a fairing in front of the bars does help.
you can buy one or make one.
https://www.autoanything.com/roof-racks/yakima-win...airing_BMM
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vanagonjr
Samba Member
Joined: October 07, 2010
Posts: 3431
Location: Dartmouth, Mass.
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| Posted: Thu Mar 26, 2020 10:14 am Post subject: Re: roof cargo box vs. MPG |
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| pdm777 wrote: |
After looking at the wind tunnel pics,
I moved my box as far back as possible.
and as low as possible. Aero
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I did a near cross country trip with a 95 Ford Escort wagon with a roof top box as far back as possible. I really track mileage and this was no exception.
I got three tanks over 45mpg, from a car that maxed out at 37-39 w/o the box.
Breaking up the suction off the rear I guess helped immensely.
Why I didn't just leave it on all the time?
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John - 86 Wolfsburg Westfalia "Weekender"
Flint reversed 1.8T W/Passat 5-Speed
LiMBO (late model bus club) www.limbobus.org
LiMBO is on Facebook too! https://www.facebook.com/groups/
FAQ thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=525798 |
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dlb154
Samba Member
Joined: December 27, 2006
Posts: 359
Location: Reno, NV
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| Posted: Thu Mar 26, 2020 2:56 pm Post subject: Re: roof cargo box vs. MPG |
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| vanagonjr wrote: |
I got three tanks over 45mpg, from a car that maxed out at 37-39 w/o the box.
Breaking up the suction off the rear I guess helped immensely.
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Interesting... Recently made a family trip to the Grand Canyon in a Honda Pilot with a cargo box on top. My parents went as well in an identical Honda Pilot without a cargo box installed. They consistantly did 3 mpg better than we did.
I like the idea of the cargo box on the Vanagon but not the lower MPG. If moving so there is an overhang on the back makes an improvement, I'd be interested in doing something similar. Only challenge would be opening the rear hatch with the cargo box installed (and overhanging). |
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dlb154
Samba Member
Joined: December 27, 2006
Posts: 359
Location: Reno, NV
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| Posted: Thu Mar 26, 2020 3:00 pm Post subject: Re: roof cargo box vs. MPG |
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| pdm777 wrote: |
After looking at the wind tunnel pics,
I moved my box as far back as possible.
and as low as possible. Aero
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What's your solution for opening the rear hatch with the cargo box installed?
Please post MPG results if you road test this setup.
Thanks! |
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pdm777
Samba Member
Joined: August 06, 2012
Posts: 348
Location: Clovis, CA
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| Posted: Thu Mar 26, 2020 11:01 pm Post subject: Re: roof cargo box vs. MPG |
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The rear hatch opens all the way!
moving the weight to the rear makes popping the top so much easier.
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1990 Westy Full Camper |
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dlb154
Samba Member
Joined: December 27, 2006
Posts: 359
Location: Reno, NV
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| Posted: Fri Mar 27, 2020 8:01 am Post subject: Re: roof cargo box vs. MPG |
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Nice!
How do you keep the cargo box from bouncing on the back end of the pop-top?
I saw your u-bolts from the cargo box to the front cross-bar. Do you have a t-slot mounted to the top for rear anchorage to the box? |
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CanStan
Samba Member
Joined: October 16, 2005
Posts: 1038
Location: Calgary, AB
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| Posted: Fri Mar 27, 2020 8:28 am Post subject: Re: roof cargo box vs. MPG |
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A couple years ago, we did a ~6000 mile / 10000 km trip in the Vanagon with a cargo box on top. I recall doing the math back then, and determining it was going to cost me about an extra $125 in gas for that trip (obviously lots of variables like speed, wind, price of gas etc. would affect that. But it would be in that range give or take).
For me, it was worth every penny to have the extra storage space, regardless of the mpg loss. So I guess that's part of the factor in this whole thing. Ultimately, would you prefer absolute best mpg, or the convenience of the added cargo space? For the average guy puttering around town, and doing the odd short out-of-town weekend camping trip, I can't imagine you would ever notice the extra fuel cost. Your particular driving style would probably have a greater positive or negative influence in the long run vs the cargo box in my uneducated opinion.
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pdm777
Samba Member
Joined: August 06, 2012
Posts: 348
Location: Clovis, CA
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| Posted: Fri Mar 27, 2020 11:25 am Post subject: Re: roof cargo box vs. MPG |
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The back part of the cargo box lies flat on the poptop,
and is secured with a large patch of industrial velcro.
It hasn't moved a hair in over a year of travels. very solid.
The goal was NO holes in the poptop!
And I agree, having a cargo box is a must for Westys.
I put camp chairs, kayak paddles, and bulky light items up top
and it frees up the floorspace inside. wish I did it years ago.
https://www.amazon.com/VELCRO-Industrial-Strength-...amp;sr=8-6
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1990 Westy Full Camper |
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dlb154
Samba Member
Joined: December 27, 2006
Posts: 359
Location: Reno, NV
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| Posted: Wed Apr 01, 2020 11:06 am Post subject: Re: roof cargo box vs. MPG |
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With over a year's worth of travel, how does this setup alter your MPG?
Any difference noticed; good or bad? Thanks! |
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vanagonjr
Samba Member
Joined: October 07, 2010
Posts: 3431
Location: Dartmouth, Mass.
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| Posted: Wed Apr 01, 2020 11:16 am Post subject: Re: roof cargo box vs. MPG |
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| dlb154 wrote: |
| vanagonjr wrote: |
I got three tanks over 45mpg, from a car that maxed out at 37-39 w/o the box.
Breaking up the suction off the rear I guess helped immensely.
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Interesting... Recently made a family trip to the Grand Canyon in a Honda Pilot with a cargo box on top. My parents went as well in an identical Honda Pilot without a cargo box installed. They consistantly did 3 mpg better than we did.
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It will be highly dependent on the car and placement. Cargo box definitely caused a reduction in gas mileage on my Civic and likely most cars, certainly on all sedans. Also, factory crossbars will make it virtually impossible to place correctly on a wagon.
Note my box was long, narrow and not too tall. It is one of Thule’s smallest. I’m an sure a bigger box would have a negative effect.
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John - 86 Wolfsburg Westfalia "Weekender"
Flint reversed 1.8T W/Passat 5-Speed
LiMBO (late model bus club) www.limbobus.org
LiMBO is on Facebook too! https://www.facebook.com/groups/
FAQ thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=525798 |
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pdm777
Samba Member
Joined: August 06, 2012
Posts: 348
Location: Clovis, CA
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| Posted: Wed Apr 01, 2020 11:45 am Post subject: Re: roof cargo box vs. MPG |
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Can't answer your question about gas mileage.
I don't track it, Too many variables on each trip.
I drive 75+mph on freeway with no regard to mileage.
Driving the Sierras, 2nd gear (auto) on the steep climbs.
Then coasting back down. Then there's in town driving.
It doesn't matter, the utility of having a cargo box
and a kayak certainly trumps mileage.
Gas is cheap, but there's no where to go ! Now go wash your hands!
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