10-21-2009, 11:29 PM
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#41 (permalink)
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Moderate your Moderation.
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Well, that's fairly accurate, except you're not going to get a good reading with only 1 mile of testing. Hell, some cars wouldn't use the fuel in the lines in 1 mile. I don't think my Civic even exchanged the fuel rail in 1 mile at 65, honestly.
They should have done an average of at least 3 20 mile runs using the same method for each mod, setting the cruise control, and attempting to stay within a set parameter for wind speed and relative temp/humidity.
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10-22-2009, 02:59 AM
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#42 (permalink)
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eco....something or other
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Now how do we dimple a car? without 1,000lbs of clay nt
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1991 F-250:
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10-22-2009, 03:35 AM
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#43 (permalink)
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Moderate your Moderation.
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Quote:
Originally Posted by IsaacCarlson
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Bring me a case of a beer and a bucket 'o balls...
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10-22-2009, 03:45 AM
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#44 (permalink)
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eco....something or other
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And maybe a golf ball cannon?
I was thinking some type of peening system but that damages paint......and I don't want to build up the surface of the car. Would dimpling a kamm-back help or would it be better smooth as the air would be more stable going into the slipstream?
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1991 F-250:
4.9L, Mazda 5 speed, 4.10 10.25" rear
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10-22-2009, 03:46 AM
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#45 (permalink)
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Moderate your Moderation.
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Paint hell. If you golf ball your car, you need Titlist White anyway, so that it matches the design.
You thouhgt you were getting off easy? Hell no.
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10-22-2009, 03:47 AM
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#46 (permalink)
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Moderate your Moderation.
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I think it's bed time. My eyes hurt.
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10-22-2009, 06:07 AM
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#47 (permalink)
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EcoModding Lurker
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Quote:
Originally Posted by Christ
Well, that's fairly accurate, except you're not going to get a good reading with only 1 mile of testing. Hell, some cars wouldn't use the fuel in the lines in 1 mile. I don't think my Civic even exchanged the fuel rail in 1 mile at 65, honestly.
They should have done an average of at least 3 20 mile runs using the same method for each mod, setting the cruise control, and attempting to stay within a set parameter for wind speed and relative temp/humidity.
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They clayed the whole car smooth, which added some weight, but then they did 5 runs and averaged them. Then they made the dimples and even put the little caps they carved out into the car so that the weight was the same as before, and then did 5 more runs and averaged them. The way they measured the fuel is probably more accurate than using a scangauge.
"26 and change" mpg for the smooth car
29.65mpg for the dimpled car
Now where's the 11% improvement? 29.65/26=1.14 That would mean it was 26.7mpg when smooth wouldn't it?
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10-22-2009, 11:38 AM
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#48 (permalink)
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Master EcoModder
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Anyone who knows a thing or two about aerodynamics will tell you dimples do not scale up to work on a car. An 11% increase in FE at 65 mph is more or less between 15 to 20% reduction in drag, that's way too much for not having been universally accepted in the past.
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10-22-2009, 12:57 PM
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#49 (permalink)
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Master EcoModder
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It's really embarrassing for them to go to an aerodynamic specialist and then fail this hard.
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10-22-2009, 01:29 PM
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#50 (permalink)
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Master EcoModder
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They said they couldn't just beat up the car because the metal would stretch and not make a true dimple. The only way I see to duplicate it without clay would be to either mold something... or take off each body panel and make a "dimple die set" and use a press to form the dimples. Or use some thin metal, dimple it with the die set, and then attach it to the car.
The air/water flow test did show improvement with the dimples, but it didn't really look like that much. I too am skeptical about 11%. I wonder what kind of air temperature or wind differences there were between all tests.
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