Roof racks suck gas, but how much?

[350outrage]

My point . . . was about choosing the equipment that does the job, period. If a roof rack is the only way to get the job done then there is no reason to fuss about the mileage affect.

You see, we agree! So go be happy!

 

[Shocker]

Just an FYI, the 2500 Sprinter is rater to tow 5,000 and the 3500 is rated to 7,500.

Personally I am a bit surprised at the little bits of vitriol flying around. Econolines are great! Sprinters are great! I would take either. Of course mine is a an old 1982 E350 with a 460. And carb'd at that!

There are a lot of great Sprinters for sale these days. Very reasonably priced, but hardly any passenger rigs. I have been hunting for a 2wd van for family use and there are dozens all over CL, but 95 percent are cargo rigs. The passenger ones are very late model and pretty high end and very nice.

On a side note, there is a guy in my neighborhood with a Sprinter 2500 and he tows a 22 foot Bayliner cuddy cabin. I think it weighs in around 4200 lbs with the trailer.

On topic, I have been thinking of adding a roof rack in the future, but VanDOOM is pretty tall as it is and won't fit in the shop with any kind of rack on it.

 

[Bbasso]

Back on topic...

I recently took my kayak off my roof and gained .7 mpg

Oh my van is a high top E350 7.3PSD.
Tow rating is 10,000 stock

 

[Michaeldinpc]

My AWD express van came with a ladder rack when I bought it. I always fill my tank up to the brim, reset the trip meeter and calculate MPG every time I fill up to keep an eye out for mechanical problems (have already caught two bad O2 sensors this way)
Anyways I noticed a consistent .5-.75 mpg increase since taking the ladder rack off.

 

[350outrage]

Back on topic...

I recently took my kayak off my roof and gained .7 mpg

Oh my van is a high top E350 7.3PSD.
Tow rating is 10,000 stock

Yeah, that's pretty close to my experience. Bolted on ladder racks and 17' canoe and it knocked about 1.5-2 mpg off. Ladder racks alone; .75-1 mpg. I drive 70-75 on the hwy with stuff up top.

 

[jungblud]

Fd = force (drag)
p = density of liquid (air) (yes you get better mpg at altitude, among other reasons)
u = velocity through liquid
Cd = coefficient of drag
A = frontal area

Fluid dynamics is a b**ch. The velocity of a vehicle increases the force required to push it through the air in a squared fashion. Double your speed and you quadruple the energy needed right there. It is a declining return on investment.

Adding stuff on top of your rack can majorly increase frontal area. The smaller the vehicle the bigger the impact. This is why trailers are a better solution for hauling lots of stuff. You literally take them out of the equation, mostly.

You can try to make stuff 'smoother' playing with the drag coefficient. But that is another linear relationship to the force.

Tim

Overall, going slower does make a huge difference. Slow down a bit and your rack and stuff will have less impact on your mpg.

 

[ujoint]

Finally finished with our roof rack design and prototyping. Using extruded aluminum and corners that we make in house to enable easy shipping in an 8" tube. Infinite adjustability, light, simple. I have a bunch of accessories ran up and ready for testing then production. This rack will get it all for demo purposes, I'll post pics in my build thread as we get them attached.

No wind noise, rack is 5 x 9.5. I'll post more detailed pics soon!

 

[jungblud]

If that is 8020 black anodized aluminum extrusion....bravo! I like the design and the lightweight approach overall.

 

[Teamoatmealpie]

I cant seem to find an off the shelf roof rack fairing that is wide enough and tall enough- I have Thule tall mounts to accommodate the rocker curve of my 17' canoe.

Thinking I need to make on up- anyone have any experience, tips or pics of what they have done?