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 roof-rack crossbar aero effect

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jasonlachapelle

jasonlachapelle


Posts : 1160
Join date : 2011-01-24
Age : 40
Location : CFB Bagotville, QC.

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PostSubject: roof-rack crossbar aero effect   roof-rack crossbar aero effect Icon_minitimeSun Jan 22, 2017 9:51 am

Someone recently posted about the vacuum by the wagons at highway speeds, and it was suggested to use the old style crossbar at the rear position to alleviate this. I can't find that post now, but I meant to get back to it.

I had never heard of that vacuum effect on the wagon or recommendation before. I've been leaving the crossbars off my caprice because I always assumed it probably helped mpg, even if it's a minute amount. Has anyone done any comparisons with/without/with just one crossbars ? Doesn't need to be super scientific.
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Fred Kiehl

Fred Kiehl


Posts : 7146
Join date : 2009-11-13
Age : 75
Location : Largo, FL 33774

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PostSubject: Re: roof-rack crossbar aero effect   roof-rack crossbar aero effect Icon_minitimeSun Jan 22, 2017 6:01 pm

The thread referred to high speed affects...over 180 MPH. Depending on the shape of the rack it may or may not help/hinder the aerodynamics. Someone would have to put it in a wind tunnel with smoke to see what the air is actually doing. I think the difference between having the roof racks on or off would be too small to measure, except for over a long time span. The other changes in the car over the time necessary to get usable results could throw the whole research initiative off.
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jasonlachapelle

jasonlachapelle


Posts : 1160
Join date : 2011-01-24
Age : 40
Location : CFB Bagotville, QC.

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PostSubject: Re: roof-rack crossbar aero effect   roof-rack crossbar aero effect Icon_minitimeSun Jan 22, 2017 7:58 pm

Fred Kiehl wrote:
over 180 MPH. Depending on the shape of the rack it may or may not help/hinder the aerodynamics. Someone would have to put it in a wind tunnel with smoke to see what the air is actually doing. I think the difference between having the roof racks on or off would be too small to measure, except for over a long time span. The other changes in the car over the time necessary to get usable results could throw the whole research initiative off.

fair enough.
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PostSubject: Re: roof-rack crossbar aero effect   roof-rack crossbar aero effect Icon_minitime

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