Roof Rack Fairing Question

[Gone2]

Okay, after much frustration with A-B-A testing and searching online forums including this one, I am having little luck really impacting the FE on my new/old Taurus wagon. The biggest frustration is an answer to the roof rack fairing question, which doesn't exist on this site either (if I have overlooked a write-up, please post the link so I can review it). I have the factory rack installed on my car, where the cross bars do not begin until almost two feet behind the windshield. The big question, will the roof rack fairing even make a difference? I have a mocked up one up there now, and it looks as though my FE actually dropped. I still think the fairings are wicked cool, especially with the stickers on the front, but is it even worth it to try?

[Frank Lee]

Can't directly answer but I took Moon Unit's crossbars out (but haven't driven it enough to notice any trend as a result).

[bikin' Ed]

I used to own a chrys. LHS on which I had a roof mounted bike rack. In my case the rack alone cost me about 1 mpg (almost 5%) at highway speeds. The difference with the fairing was not noticable except the wind noise was less. With bikes on the rack it cost me 4-6 mpg at hwy speeds.

The answer in your situation will take a tuft test and a friend with a vehicle tall enough to see the tufts on your roof.

[Monkey1]

Hi Sentraguy,

I just wrote about this . Here is a partial quote from the article:

"There are three primary factors that determine the amount of drag from roof rack components: speed, frontal area and drag coefficient. How fast you drive is up to you, but clearly the frontal area of a fairing is substantially larger than that of a set of crossbars. In fact, it is probably in the neighborhood or 5 or 6 times the frontal area or even more. Further, the drag coefficient for the triangular shape made by a fairing is likely to range from 30% to 225% higher than typical square and round crossbars.

The aerodynamic drag is calculated, in part, by multiplying the frontal area by the drag coefficient. Clearly, the drag produced by a fairing will be substantially higher than that of the crossbars by themselves."

Almost without a doubt, wind noise will be reduced, but your mileage cannot improve and will likely drop farther by using a fairing. The best options are to get your attachments off the crossbars and, even better, buy aerodynamic crossbars or take them off altogether when not in use.

Tom

[Gone2]

Thanks, that is basically what I figured. I have the fairing off and will try it out next week. I also found out I have some transmission issues that may be affecting my tests.