Aero modding?

MGregoir

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It's funny, right after this post somebody offered to sell me a five speed Cavalier coupe for $300 because it needs a clutch. It's recently painted and has new tires and I know it is in good running condition other than the clutch...hmm. I am not interested so much in the eco-modding thing as just taking a dime-a-dozen car and seeing what kind of mileage I could get out of it at highway speed. I wouldn't use it as a daily driver but if I proved the fuel economy of it, I would be interested in taking it in a long distance drive to see what the range is and do a bit of touring.
 
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Dallas, TX
Drivability is a big factor. The car pictured above couldn't be driven on anything but a race oval without serious damage to that nose. I'd never get it in or out of my driveway...and it's appearance would have it banned from my driveway anyway.
 
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I don't believe those highway MPG numbers for that Civic nor its drag coefficiency of 0.17 How much extra weight was added to his Civic with all those panels attached to his car ?
 

MGregoir

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The realtively un-radical looking GM EV1 had a drag coeffecient of 0.19. Based on a drag coeffecient of 0.18, a vehicle weight of 3000 pounds and a frontal area of 20 square feet, a vehicle just about takes more power to run an alternator and air conditioner than it does to get down the road at cruising speed. A Cavalier can get 35+ miles per gallon with a drag coeffecient of 0.36...dropping to 0.24 would be a 1/3 reduction in drag and comparable to a Mercedes CLK. I believe the lifetime average of 65-ish mpg for his Civic.
 
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65 MPG for the Civic VX and CX hatchback is very reasonable, especially if you hype mile and use every trick in the book to save gas. But the aero mods this guy did to his Civic is night and day difference from the GM EV1 that was designed in a wind tunnel.
 
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Ontario, Canada
Did you click on the fuel log link? Realistically to achieve an average of 64mpg he has to have a cruising mpg way way up there. My car at 50 mph on a level road will get around 50mpg, and I average about 34mpg for a tank. The extra weight of the panels doesn't really hurt his mileage as he does mostly highway driving, other than a tiny increase in tire drag there's no penalty to the extra weight once at cruising speed.
 

MGregoir

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Both of these cars have drag coeffecients of 0.19, I'd believe that that Civic is down in the 0.19 to 0.22 range for sure. Maybe not 0.17. but right down low. That is what 0.15 looks like.
 
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Def get the car, even if the fairings don't work out you can return it to stock and sell it at a tidy profit.
 
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Well smooth is sort of important but reducing the size of the turbulent wake is far more important. The patched together civic looks like it has a much smaller turbulent wake than any of the cars above. Look at the fuselage of a cessna, the front motor and windshield don't look to aerodynamic but the fuselage tapers down to the tail leaving a tiny wake behind it. Have a look at a prius, insight, fit, even a mazda5, you will see that they begin to taper the back end to reduce the size of the wake.
 
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Perris, CA
 Originally Posted By: MGregoir
A Cavalier can get 35+ miles per gallon with a drag coeffecient of 0.36
In that case, I really must use the "make lots of noise" pedal way too much...
 
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Upstate NY
With some "basic" aeromods you can get some nice gains. I have a 3-season grille block and recently added some deflectors to the underbody to deflect air away from the front lower control arms. I'm getting 34-35 mpg out of a Buick LeSabre at 70 mph with A/C on, more if I slow down. With summer-blend fuels and some basic work on that Cavalier, seeing >35 mpg would not be hard.
 
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