Aero tips, tricks

Aerodynamics play a big part in a vehicles fuel economy. Witness all the newer big rig trucks with their aero rounded fenders and flarings and such. With that being said, what sort of aero tricks, both practical and unpractical, could we apply to our cars and trucks to make them more slippery. Just for fun. I will start with the tailgate up/down debate. I read a report that there is such a small difference it is not worth trying. I verified that once with my little truck and a scanguage. But a bed cover is supposed to decrease wind resistance. Did not verify that. Any other tricks?
 
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1,463
Location
CA
European Car covers aero in this month's issue. It's worth a quick read. Lowering your vehicle and thinner tires help a quite a bit. Big mirrors really hurt mpg's, as does a larger frontal area or poor drag coefficient. I read in R&T a ferw years ago that a Canadian gov't agancy (Transportation Dept?) had their super computer working on the tailgate up/down thing. IIRC, up won out by a couple %. Down caused more turbulence behind the bed.
 
Messages
783
Location
Austin Texas
The biggest improvement to automobile aerodynamics (that is easy to pull off) is a complete underbody aerodynamics 'tray'. This device allows the air to flow under the car with significantly less turbulance and drag, by hiding all of the air disturbing components under the car. Weight about 20 pounds.
 
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10,843
Location
Nokesville, VA
quote:
Originally posted by gtx510: I read in R&T a ferw years ago that a Canadian gov't agancy (Transportation Dept?) had their super computer working on the tailgate up/down thing. IIRC, up won out by a couple %. Down caused more turbulence behind the bed.
Mythbusters also tested that and they came to the same conclusion.
 
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3,202
Location
Far North East Texas
IIRC, wind resistance increases with speed as the difference in squares: so, if you go twice as fast as your "base-line" speed, whatever that is, you'll face 4 times the air resistance. Three times as fast, nine times the resistance, etc. If I've remembered wrong then I bet someone will straighten things out quickly. [Wink] But: If I remembered correctly, then it produces this handy little factoid: divide 60 squared(3600) into 75 squared(5625) = 1.5625. So if resistance increases as difference in squares, at 75 mph the same vehicle faces 56% more air resistance than at 60 mph. [Eek!] [Cheers!]
 
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783
Location
Austin Texas
When measured in lb-ft (e.g. torque consumed) force consumed from air resistance does go up with the square of velocity. When measured in power, air resistance consumes cubic amounts of HP with increasing speed.
 
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180
Location
New England
Following on Mitch's comment, I'd bet a front air dam, full width, as low as possible, would be of benefit. I made one for my track car (for a diffeent reason of course) from stiff rubber similar to what's used for big-rig mudlaps, and some Home Depot hardware (I should call the car The Home Depot Special). It flexes fine over steep drives, curbs, etc.(can't say the same for the brake ducting, though)
 
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395
Location
California
Would it be worth the effort to take external mirrors off cars and use a couple of cameras? They could improve your rear vision, remove blind spots, be used for backing into parking places, too.
 
Messages
570
Location
Maine
quote:
Originally posted by Louie's gone fishing: Would it be worth the effort to take external mirrors off cars and use a couple of cameras? They could improve your rear vision, remove blind spots, be used for backing into parking places, too.
not if your car won't pass your state's (if your state has one) safety inspection. here in Maine, mirrors are specifically required by law AND a video display in view of the driver is specifically denied by law.
 
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2,187
Location
Arizona
Wheel-well covers (for the non-steering axle, for all the geniuses out there) can be helpful. You can make your own for many vehicles with some plexiglass-type stuff and some aircraft tape. Disclaimer here about finish quality when you remove the tape.
 
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7,077
Location
Ontario, Canada
Wheel well covers on all four wheels will improve MPG at 75 mph by about 10%. Covering the radiator grille (but only when it's below freezing) will give about 3% improvement. Cover it half way in cool weather, for a cheap 1% mpg gain at highway speed.
 
Messages
3,329
Location
Bolivia
The best thing I have done for my 4Runner is add a rear spoiler. Although not posting my entire 6 year history, it was constantly between 7 to 9 km/L. The *** is the first tank with the spoiler. Obviously mileage varies with driving speeds, mountains, etc. The first leg of next saturday's trip in this 4Runner takes about 50 liters if I keep it below 100 kph, but if I push it to 130 I have to make an extra stop for fuel, so it takes longer. 8.14 7.82 7.93 8.15 9.08 7.20 8.63 9.76 8.54 10.09****** 7.99 10.18 9.17 11.66 10.89 9.43 8.91 10.49 6.92 11.83 10.26 10.10 9.95 9.48
 
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