20% fuel saving with simple roof rack mod
 

Our 2011 Prius fuel use was 5 litres /100km for highway driving at 110 kph. I installed roof racks and fuel use went up to 6 L/100km.

I built a lift-neutral airfoil for each cross bar using western red cedar. The fuel use returned to 5 L/100 km. Wow, I was impressed that a simple mod could make such a huge difference!

I installed a ski box onto the racks without any change in fuel economy. The cross bars seem to be the drag spoilers here.

Pics?

Ski box did not add any drag?

That is fairly amazing.

But we do need pictures :)

You need five posts before you can submit pictures, which we greatly want to see. Just click on these four threads I started, tell me to do push-ups, and you are in business:

http://ecomodder.com/forum/showthrea...ise-35554.html
http://ecomodder.com/forum/showthrea...ity-35544.html
http://ecomodder.com/forum/showthrea...bay-35543.html
http://ecomodder.com/forum/showthrea...val-34642.html

Can someone find a good explanation of tuft testing? I do not see anything on the wiki. Thanks!

This google search will take you to well written wool tuft testing articles

https://www.google.com.au/search?q=a...HIXp8wfrvJCwCA

Its kinda no-brainer that majority of racks have many flat surfaces. Considering the fix is easy and looks good as well.