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Old 02-15-2015, 02:36 PM   #1 (permalink)
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0.201 cd Camaro

Car Aerodynamics - Hot Rod Magazine

A very vague Hot Rod magazine article. How did they get this Camaro down to a 0.201 drag coefficient? It doesn't seem to jive with what I see in this forum.

And:
"The biggie: windshield rake: According to Eaker, "Here's a myth I can bust. Once the windshield is past 45 degrees of rake-and many stock cars average like 60 degrees-you will not see an improvement from laying it down at an even steeper angle." We proved this on the Camaro, building a hugely sloped "windshield" out of foam core. It did nothing."

A 45* windshield is old car territory. I want to use an old car for mpg aero.


Older post Re: http://ecomodder.com/forum/showthrea...tml#post127860

And: http://ecomodder.com/forum/showthrea...lle-30678.html


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Old 02-15-2015, 02:54 PM   #2 (permalink)
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It boggles the mind how that things we perceive as 'aero' can be bricks, and bricks, such as this car are more streamlined than anything currently in production ( except the XL-1. )

Also of note is the fact that the scoop ( yup - the one in the picture ) did NOTHING to the drag of the car. It was the same Cd with a flat hood !
Look at the wheels sticking out in the breeze - the rear wheels. When Eaker tested the factory deflectors ( spats ), they did NOTHING to the drag, but increased downforce.


At the time of the test, the car did not have a belly pan. Look at all the junk hanging down under there !
( The car was later fitted with a pan to race in Australia, but was tunnel tested without it ! )
Look at the panel gaps on that thing. Only the front end was sealed ( its a fiberglass front end )

I have to say that now I have gained an entirely new appreciation for that body style.
Thanks for posting.
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Old 02-15-2015, 03:04 PM   #3 (permalink)
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By the way, this is the same tunnel that ran the " Drag Queens " test. The Cd counts are valid.

Drag Queens: Aerodynamics Compared – Comparison Test – Car and Driver

I emailed the guys at A2 and they are really helpful and polite. I wish we could have a 'VIP guest' question thread on this forum.

They wouldn't have much time to answer that many questions, but i think their knowledge would be a boon to all of us !

Oh - and one more thing ..I can already hear Frank Lee grumbling " NOT THAT CAR AGAIN !! " ;-)
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Old 02-15-2015, 03:37 PM   #4 (permalink)
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Quote:
Originally Posted by sgtlethargic View Post
...How did they get this Camaro down to a 0.201 drag coefficient?
I don't know, but some of what they are doing cannot be done on street cars, like radical lowering, a road scraping airdam, and that massive cowl. The cowl might be huge but they sealed it to prevent air going in except for when they want to ram it in the intake. The radical lowering also improves the fineness ratio. I guess the answers are in some of those things... and maybe they have shaped the parachute junk in a way that acts a little like a box cavity or something. But honestly... aerohead...? ... you out there?

But I would say that their list of fi reliable aeromods echoes what is commonly recommended here...
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Old 02-15-2015, 03:39 PM   #5 (permalink)
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WTH????

That's crazy!!! I would of never guessed the Cd down to that?
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Old 02-15-2015, 04:22 PM   #6 (permalink)
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Quote:
Originally Posted by California98Civic View Post
I don't know, but some of what they are doing cannot be done on street cars, like radical lowering, a road scraping airdam, and that massive cowl. The cowl might be huge but they sealed it to prevent air going in except for when they want to ram it in the intake. The radical lowering also improves the fineness ratio.
don't forget no mirrors or grill opening
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Old 02-15-2015, 04:29 PM   #7 (permalink)
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Wow! That is impressive. I would have thought increasing the frontal area with that huge lower air dam would have hurt more than helped. Good article and good find.
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Old 02-15-2015, 06:22 PM   #8 (permalink)
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[QUOTE=California98Civic;468101]I don't know, but some of what they are doing cannot be done on street cars, like radical lowering, a road scraping airdam, and that massive cowl.


I have seen plenty of cars riding low. I think there are a few of us here that have a 'road scarping ' airdam.

I think this design is just a diamond in the rough. The stock Chevy Camaro from the same year has a Cd something like .487 if IRC. and all it took to get to .201 was to plug the grille / front openings, add a ( barn door) front air dam, lower the car , remove the mirrors, add a spoiler and moon wheels and BAM ! Instant drop of over 50 % !

Do all that to the car you are driving today and I bet you wont see nearly the same Cd.

Air flows in strange ways.

and the cowl ?
The car tested the same Cd with and without the "cowl" ( did you mean scoop ?




For all you math guys out there, something I wonder about this car since that article came out is how much of an increase in MPG a car like that would have. Just for comparison sake.

If a stock 1980 Camaro with a Cd of .487 got around 20 mpg on the highway, what kind of an increase would it get if brought down to a .201 ?

What about if the car were getting 35 mpg ?
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Old 02-15-2015, 06:30 PM   #9 (permalink)
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Just look at the wheel gap above that wheel in the picture I posted ! ( post # 2 )
One would think that the air would be turbulent there.
And keep in mind the Cd was the same with and without that air deflector ( spat ) they have taped on there. You would think the air would smack right into that tire and go turbulent !
No boat-tailing behind that tire either.
Stock door handles too ( non flush )

Perhaps Gary Eaker is just a brilliant guy that knows how to tune a car to perfection.
He did after all work on the aerodynamics of the EV-1.
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Last edited by Cd; 02-15-2015 at 06:37 PM..
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Old 02-15-2015, 07:08 PM   #10 (permalink)
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What I wonder is why the stock body tested at 0.487. That's as bad as a VW Beetle, with much advantage in fineness ratio and overall shape. I suspect that a lot of the advantage is in the contour of the back half of the roof—lots of tumblehome and similar to the GM EV-1. aerohead reports 10% of his drag is from the rear-view mirrors.

Rear wheel spats: Increased downforce without increased drag is a win. Left on the table: A massive rear diffuser.

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