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Old 06-08-2014, 10:57 PM   #11 (permalink)
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Follow Aerohead's advice, and/or look on this website for pics of various Miata noses, the best of which combines rounded nose/airdam/splitter, effectively what Aerohead said.

You could use Coroplast and make an undertray which extends forward becomes a splitter, joined with the airdam, which should curve laterally outward to fair the flow past the leading edges of the tires. Airdam, slpitter, and undertray would structurally support each other. Use nice, gentle elliptical curve for the airdam.

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Old 06-08-2014, 11:16 PM   #12 (permalink)
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An underbody is usually better than an air dam. Rather than moving through the air in as smooth a manner as possible, you are increasing frontal area (and possibly Cd) to try to influence how the air is moving, which regardless of the strength of the dam, and continuing under the vehicle.

I am not trying to discredit the airdam, just that an airdam is the way to go when an underbody can't be done. I couldn't believe anyone would choose (all things being equal) an airdam over an underbody.

On the topic of an airdam, everyone here makes good points. Strength of it is a pretty important factor when punching through the air, if it is deforming then there may be issues. I have no ABA testing, so take this with a grain of salt, but after my underbody was complete, at one point my dam was ripped off. There was no loss whatsoever in MPG, actually it increased. I can't provide data to a quantitative result, but from personal experience, an airdam or splitter is a negative when an underbody is clean.

(Although an underbody may in be place, air should still be diverted around the tires if possible. Jedi Sol has an OEM looking build for them, and others have done great jobs as well.)
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Old 06-09-2014, 09:59 AM   #13 (permalink)
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I went to 2" above ground on my VW. It lowered the MPG about 2mpg. I was surprised, felt that it was because it increased the frontal area. I felt that that close to the ground that the airflow was stymied from interference drag.
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Old 06-09-2014, 01:02 PM   #14 (permalink)
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airdam/Belly pan

Quote:
Originally Posted by UltArc View Post
An underbody is usually better than an air dam. Rather than moving through the air in as smooth a manner as possible, you are increasing frontal area (and possibly Cd) to try to influence how the air is moving, which regardless of the strength of the dam, and continuing under the vehicle.

I am not trying to discredit the airdam, just that an airdam is the way to go when an underbody can't be done. I couldn't believe anyone would choose (all things being equal) an airdam over an underbody.

On the topic of an airdam, everyone here makes good points. Strength of it is a pretty important factor when punching through the air, if it is deforming then there may be issues. I have no ABA testing, so take this with a grain of salt, but after my underbody was complete, at one point my dam was ripped off. There was no loss whatsoever in MPG, actually it increased. I can't provide data to a quantitative result, but from personal experience, an airdam or splitter is a negative when an underbody is clean.

(Although an underbody may in be place, air should still be diverted around the tires if possible. Jedi Sol has an OEM looking build for them, and others have done great jobs as well.)
Here is a link to an image of the 1983 Ford Probe-IV Cd 0.154 concept with active aerodynamics.
Even though this car has a 'perfect' under body,Ford found lower drag with lowering/raking/and an active airdam.
Sorry,link won't work from as EcoModder thread.
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Old 06-09-2014, 01:06 PM   #15 (permalink)
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Quote:
Originally Posted by aerohead View Post
Here is a link to an image of the 1983 Ford Probe-IV Cd 0.154 concept with active aerodynamics.
Even though this car has a 'perfect' under body,Ford found lower drag with lowering/raking/and an active airdam.
Sorry,link won't work from as EcoModder thread.
Can you PM it? I would love to know more. I only know from my little experience, and it is dwarfed by your knowledge and experience on it- if you could share it I would be much obliged lol.
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Old 06-09-2014, 01:25 PM   #16 (permalink)
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PM

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Can you PM it? I would love to know more. I only know from my little experience, and it is dwarfed by your knowledge and experience on it- if you could share it I would be much obliged lol.
I've got a better image at home that I'll bring.It will have to be scanned,photo-shopped,and exported into PhotoBucket,which means maybe a delay,but it will be a larger,clearer image.I'll get that tonight and see about it tomorrow.
In the meantime,a GOOGLE search for 1984 Probe-IV active aerodynamics should get you something to look at.
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Old 06-09-2014, 08:18 PM   #17 (permalink)
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1983 Ford Probe-IV - Google Search points back here:
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Old 06-09-2014, 08:22 PM   #18 (permalink)
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Old 06-09-2014, 08:55 PM   #19 (permalink)
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Quote:
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I built up a bicycle streamliner that instead of having a front rear and back front strake, it had a single strake that connected the two. It set the record.
Picture?
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Old 06-09-2014, 08:59 PM   #20 (permalink)
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Sure

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