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

http://ecomodder.com/forum/attachmen...5&d=1424028601

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.
http://image.hotrod.com/f/10214175+w...side_spats.jpg

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.

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 !! " ;-)

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...

WTH????

That's crazy!!! I would of never guessed the Cd down to that?

don't forget no mirrors or grill opening

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.

[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 ?

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.

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.

This is from the article :

For comparison with our modified Camaro, A2 also tested Dave Matyjasiks closer-to-stock version. Without the grille plug and air dam and with no spoiler but with a lowered ride height and omitted rearview mirrors, the Cd was 0.497. Adding the grille plug and air dam dropped it to 0.337, then a rear spoiler that mimics the one from the HOT ROD Spl. dropped it to 0.292. Meanwhile, tricks on the HRM Spl. got the Cd as low as 0.201. Thats more than a 50 percent improvement from stock, which is enormous.

Read more: Car Aerodynamics - Hot Rod Magazine
Follow us: @HotRodMagazine on Twitter | HotRodMag on Facebook

Top 5 Easy Aero Mods That Almost Always Work
We pressed Eaker to give us clues about simple aero tricks for typical musclecars-stuff that will work nearly every time even without tunnel testing. The delta between Cd numbers is often referred to as "counts," or thousandths of a point, so the difference between a Cd of 0.250 and 0.200 is 50 counts. Eaker gave us some rough estimates on how many counts of Cd you might improve when these mods are applied to a typical older musclecar. Try these next time you're at the track.

Lower the ride height: "Dropping the car-front or rear-will always reduce drag." On our Camaro, raising the tail 1.5 inches changed the Cd from 0.201 to 0.227.Improvement: At least 20 counts per inch

Block the grille: Eaker's tip is "Always get air around the car rather than through it." Stopping air from entering the grille has shown dragstrip e.t. reductions of a tenth or two even on 120-mph cars. This will also reduce front-end lift, and when the front end raises due to lift, drag increases even more. (Bonus tip: Stiff front springs can also help prevent front-end lift). Grille blockage is more effective on older cars than on newer ones with sealed radiator areas, and obviously, it can only be used for short-duration events due to reduced engine cooling.
Improvement: 15 to 30 counts of reduction in Cd and 50 to 100 counts in reduction of Cl

Add a front air dam: "You can usually get 90 percent there just by adding a dam straight down from the front bumper, just like the one on your Camaro." Even Bonneville guys ask us why we have that big barn door on the front of the car, but keeping air out from under the car both reduces drag and neutralizes lift for solid aero gains.
Improvement: 20 counts less drag, 50 less lift. The taller the car sits, the more important the air dam is.

Seal the back of the hood to the cowl: This is another area that's less critical on newer cars that are already well sealed. Cowl-induction hoods have a high-pressure area at the base of the hood. Air does not travel out the back of the hood; it is forced down into the engine compartment. That air must escape through the car, causing flow disruptions and drag.
Improvement: 10-20 counts less drag, 50 to 75 in lift

Remove the outside rearview mirrors: Factory mirrors hanging off the doors are almost always obstacles to airflow. The '94-up Chevy Impalas and Caprices are notable exceptions; on those cars, the Cd actually gets worse when you remove the mirrors.
Improvement: 10 to 20 counts of drag



Read more: Car Aerodynamics - Hot Rod Magazine
Follow us: @HotRodMagazine on Twitter | HotRodMag on Facebook

I'm thinking front air bags (adjustable ride height) and an air dam would work well together.

Now this seems like a "real" wind tunnel picture, as opposed to the single smoke stream going over the top.

That's a different tunnel. Also, the smoke stream is adjustable.
The AeroDyn windtunnel is comprised of two tunnels, with the main ( high dollar ) one being quite advanced.
https://www.youtube.com/watch?v=o2xLjqq2RqI

I was surprised at how well the Camaro lines up with the AST. Thanks to seifrob and orangustang for the online AST tool- I've used it a lot.

Ast
 

Here is the Firebird of the same vintage
http://i1271.photobucket.com/albums/...d2/06-2829.jpg
*With the Camaro's actual nose on the ground,the frontal area isn't aggravated that much.
*The minimized airdam gap lowers drag (Feisal Ahmed's Masters Thesis)
*With the sealed nose,we lose the entire cooling system drag.
*Cooling fan delete (1-hp @ 70-mph/ 8-hp @ 140-mph/ 64-hp @ 280-mph)
*With the nose down,the max camber point of the roof is moved aft,and the separation line with it.
*The nose drop also alters the apparent contour of the windshield header.
*The dropped nose kills the second stagnation point at the cowl.
*The Pro-Comp scoop alters the windshield area pressure spike due the favorable change in sectional density.
*The Pro-Comp scoop saves 150-hp due to reduced drag,compared to the exposed blower,scoop,and drive.
*Wiper delete.
*Mirror delete.
*The rake also affects the apparent backlight to boot geometry.
*The spoiler extension improves the fineness ratio.
*The 'flat' spoiler also kills any upwards deflected 'jet' of the original up-swept spoiler.
*The drag chute 'stuffs' some of the near wake.
*This car was tested with a full aluminum belly pan.
*The big GOODYEARs close some of the wheel/body gap,cleaning up the side flow a bit.
*MOONs are good for delta Cd 0.024.(GM's measurement at Lockheed Marietta)
*All these big and little things add up.:D

BIG numbers are typically comprised on many, many LITTLE numbers.

Thanks for the replies

So it looks like this era of Camaro/Firebird are a good candidate for MPG. Reduce weight, transplant a smaller engine, air dam, lower/air bags, rear spoiler.

Plus it can be had with a T-top. And a screaming chicken on the hood. :thumbup:

I think the chicken is easily worth 5-10 more MPG making the Firebird the better candidate over the Camaro lol

candidate
 

A neighbor in Woodland Hills had a T-Bucket roadster with the Iron Duke 4-banger.Cadmium plated naughty bits,burnt orange lacquer,and stripes by Von Dutch.She went well,looked great,garnered Bo a lot of attention and trophies,plus was easier on the wallet.
The Camaro/Firebird might be a real sleeper.:)

Looks like the same tunnel to me.

C&D:

http://media.caranddriver.com/images...-s-986x603.jpg

HRM:

http://image.hotrod.com/f/10214133+q...front_view.jpg

From A2's own website:

http://a2wt.com/images/A2%20Wind%20T...%20Section.JPG

The Car & Driver article, in keeping with their "super-secret testing facility" nonsense, simply photoshops out the A2 logo.

Here's the Aerodyn tunnel, on the same campus, but larger and with a different fan arrangement:

http://www.rsrjaguar.com/Portals/0/n...1/7.5.11_1.jpg

I think you are right, but there are some new square lights on the ceiling, and round lights that apparently were added since the Camaro test.
Good eye mate !
I hadn't looked hard enough at that first Tesla image to see the similarities.
I didn't know the image was from the Drag Queen article, and thought it was just a random image.

As far as using a Camaro as a car to mod for MPG, what would the car weigh with a Japanese 4 cylinder transplant ( OH THE HUMANITY !!!! )