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Old 12-03-2014, 12:22 AM   #11 (permalink)
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Re: the coasting.... Go faster.

Also, I've NEVER been able to get such stability in any testing! You're much better at this, or is it possible it was just a fluke?

I was able to measure a ~4% improvement in MPG in A-B-A testing of the much larger Kammback/extension I made for my Firefly. Considering the one I made is significantly longer than your car's (and the starting Cd was significantly higher), I'd expect your results to be harder to spot. Looks to me like Mitsu did a good amount of the initial work with the factory spoiler.

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Old 12-03-2014, 09:34 AM   #12 (permalink)
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Yeah, Kamm extensions are good on older cars with horrible aerodynamics. Seems like most all the cars made after 2000 or so have really dialed in the aero, and anything we do to try and "Improve it", short of going full boat tail, will either be insignificant or will make matters worse.

Grill blocks are always going to be good to do because the cooling systems are designed for 120F days, going up a mountain, fully loaded, with a tailwind, and behind a semi truck for 6 hours. Since the only hill in Florida is the one by your house.....you'd be safe to choke off a little radiator air supply. (JK about the hill, I drove through Tallahassee on I10 a few weeks back, hilly area)

So I think what Aerohead was trying to say, and it's something I really believe, the way the all air comes off the back of the car should be moving as perpendicular to the direction of travel as possible. As soon air starts to move sideways to that, you are creating large swirls of air that take energy to create and thus rob you of mpg's. The object of the aero game is to leave the air molecules you drive through right where they were before you rammed through them with you vehicle. The more the air moves around, then the more energy you're using with no gain.

Great job on the build though, looks really nice.
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Old 12-03-2014, 10:10 AM   #13 (permalink)
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OT: but don't forget an air dam. A-B runs showed a positive effect on the Mirage loaner I had from Mitsu Canada.



From: http://ecomodder.com/forum/showthrea...ini-29182.html
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Old 12-03-2014, 06:16 PM   #14 (permalink)
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play time

Whatever the results,we all learn.
I think Dyson had 5226 vacuum cleaner prototype failures before he finally nailed it.42 years of failures and now he's a knighted billionaire.
Thanks for taking the time and sharing.
You're certainly barking up the right tree.
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Old 12-03-2014, 08:26 PM   #15 (permalink)
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Quote:
Originally Posted by MetroMPG View Post
Re: the coasting.... Go faster.

Also, I've NEVER been able to get such stability in any testing! You're much better at this, or is it possible it was just a fluke?
Yup,I may have to go faster next time. I could not believe the stability during testing neither.
I also aborted one of the runs due to a truck coming out of the woods in front of me. Had to turn around,go again.

A few years back when I did a Kamm back for my 94 mazda protege,(sedan)I could FEEL it hurting driving to my coasting hill! And then sure enough the MPH numbers did not lie when doing the A,A-B,B so took it right off. that was steady 2-3 MPH worse than rolling without it.(same testing site)


Quote:
Originally Posted by ChazInMT View Post
... Since the only hill in Florida is the one by your house....
Haha that's funny and probably true!

About the grillblocks and airdams,I'm already sporting a little lawn edging,some plastic and some foam on the front:



(had to cut vertical slits on the airdam to allow flexing on contact)

Also I will take all the 'ballast' out of the car to make it as light as possible for next testing!

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