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Aerodynamics of front end.
https://www.slantsix.org/forum/viewtopic.php?t=46841		 Page 4 of 5
Author:  slantvaliant [ Sat Nov 05, 2011 6:56 pm ]
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One approach to A-body aerodynamics for open road racing (Photos from the 2005 Big Bend Open Road Race):

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Not showing much lift at speed:

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The car was entered in the Grand Touring Class with a target speed of 120 MPH. He was under by 0.020 MPH on a total of 118 miles.
Author:  Reed [ Sat Nov 05, 2011 7:11 pm ]
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So he's using 67 Dart front fenders, a 68 Dart grille, and a 69 Dart body? I'd like to see the slant he's got stuffed under the hood! 8)
Author:  emsvitil [ Sat Nov 05, 2011 9:57 pm ]
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Too blocky/bulky looking.


You need stealthy aerodynamics
Author:  exoJjL [ Sun Nov 06, 2011 12:50 am ]
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Quote:
Too blocky/bulky looking.


You need stealthy aerodynamics
Yup took the already blocky front and made more block...that and I could be wrong here but it seems to just lower the air flow underneath the car and direct a little air flow past the tires.
Author:  Sam Powell [ Sun Nov 06, 2011 6:03 am ]
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It was photos of that car that inspired my air dam install about 19 months ago. I had seen only the front low perspective shot, and had not seen the other views. It does look blocky, but I bet it works. You can see that he has put air blocks behind the grill between the headlights and the radiator core. I would paint mine black. That is more inspiration. Thanks for posting those.

I think the rear spoiler looks like it follows Kamm's principal. It does not look great, but I can imagine filling that in so it has more design appeal. My brothers old Saab 90S had a rear spoiler on it that felt like it was made out of dense foam. I wonder if one could find one of those in a junk yard.

I went on line to Year One to see what mother Mopar did, and this is what I found:

http://www.yearone.com/serverfiles/fbsh ... .asp?cat=1

It seems like maybe this does not really do what the Kamm effect requires, and that is to lift the air just as it leaves the back of the car.

My Brother's 05 Mustang on the other hand has a rear spoiler that almost touches the deck at it's front edge, and then lifts the air as it departs from the back. I was wondering if I could adapt a Mustang rear spoiler to the Dart. Now here is the really important question: What color should the rear spoiler be? I am, planning eventually putting bumble bee stripes around the rear.

Sam
Author:  Sam Powell [ Sun Nov 06, 2011 6:13 am ]
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Quote:
So he's using 67 Dart front fenders, a 68 Dart grille, and a 69 Dart body? I'd like to see the slant he's got stuffed under the hood! 8)
It says 418 on the hood scoop, (facing the correct way) but is that a bow Chevy blow tie on the front of the scoop? I don't understand why he could not average 120 with any engine of 418 ci. Maybe lots of twisties in the course.

What is that truck lid off of? Reed, I think you are right about the other ID's; '69 rear quarters and tail lights, and 68 grill. I suspect the front fenders are fiber glass which would come with no marker light cutout.
Sam
Author:  Danarchy [ Sun Nov 06, 2011 9:07 am ]
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Image
Author:  slantvaliant [ Sun Nov 06, 2011 1:01 pm ]
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I don't understand why he could not average 120 with any engine of 418 ci. Maybe lots of twisties in the course.
60 sweepers, bends, turns, and corners in 59 miles, significant elevation changes, done Southbound in the morning, then Northbound in the afternoon. And the goal is to average EXACTLY your target speed. I'm sure that Dart could go a lot faster. The Tech Speed (speed limit -radar enforced!) for that class is 140 MPH. Yeah, there's a minimum speed, too.

More info on BBORR HERE. Yes, there's a Valiant on the home page. Mine!

Other interesting aero photos from the event:

'72 SAAB Sonett (highly modified, SBF, RWD, etc). Front end lift - the splitter was nearly on the ground at rest. Note the disintegrating side skirts.

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Mustang II

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Falcon ragtop - 130 MPH target speed!. Convertible tops "balloon" at speed, showing a lot of lift over the roof.

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Author:  Sam Powell [ Sun Nov 06, 2011 6:29 pm ]
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Quote:
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Is that a factory photo, or photoshopped?

Sam
Author:  slantzilla [ Mon Nov 07, 2011 2:49 pm ]
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I believe that what appears to be a roof spoiler is actually something laying on the ground behind the car. Air mattress maybe?
Author:  sandy in BC [ Mon Nov 07, 2011 3:58 pm ]
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. Air mattress maybe?
Judging by the look on the young ladies face i believe you are correct.
Author:  Old Car Scott [ Thu Nov 10, 2011 10:33 am ]
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Howdy guys!! 8)

I posted before about the aero mods, I was wondering particularly about the rear window vortex generators.

I have a baseline now for my Valiant, about 22mpg @ 3200rpm on the freeway, so now I can start documenting how certain changes affect the economy of my car.

I'm with Sam, I don't want to modify the look of the car too far from stock, but if I can pick up some additional MPG that would be great.

I will be adding an OD tranny and doing exhaust work, but I have a list of experimental aero mods.

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First on the list is a front spoiler or air dam. I built a nostalgic NASCAR looking one out of aluminum for a 1973 Satellite I used to own that really worked well, you could feel the increase in high speed stability on the freeway but it was kind of a snow plow that dragged going in and out of my driveway. I'll probably copy the design to a degree on the Valiant.

I also looked at what Chrysler was doing in 1968 to the future Dodge Charger 500.

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First they replaced the parachute grill of the '68 Charger with the flush one of a '68 Coronet to aid pushing the air around the car. Next, the installed a rear window plug to smooth the air from the tunneled rear window. Finally, they installed wide stainless front pillar moldings.

While the grill on my '67 Valiant should be real easy to clean up aerodynamically but I'm not sure what you can do about the Dart.

The rear window was of concern to me, because as noted earlier by Dart270 they seem to cause a bit of aerodynamic drag. Spoilers to smooth the air out it goes over the top work but I'm thinking I'm going to try vortex generators ala the Mitsubishi whatever it's called...

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I kinda like the way the diffusers/generators look as opposed to a wing, but I haven't tested them yet. I was thinking about making them magnetic so I could experiment with different positions and quantities.

I'm not sure how I want to handle the air coming off the decklid. I'm thinking of small vintage NASCAR-esque rear trunk spoiler to direct off the lid but I haven't really done enough research yet. I'm not looking for downforce, just make it more slippery.

That's about all I knows! Just figured I'd post what I'd been thinking about! :wink:
Author:  Dart270 [ Thu Nov 10, 2011 10:49 am ]
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I love the magnetic attachment idea. I bet you could also do that with a rear spoiler or above-the-rear-glass wing. Might look into that...

Lou
Author:  Reed [ Thu Nov 10, 2011 12:54 pm ]
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AirTab
Author:  Danarchy [ Thu Nov 10, 2011 12:59 pm ]
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Quote:
Is that a factory photo, or photoshopped?
:lol:

Totally photochopped! :lol:
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