Aerodynamics Improvements • The Dodge Challenger Message Board

by **Moparman1972** » 04 Dec 2009 14:11

Hey all. I've been tossing ideas around quite a while for aerodynamics improvements to my challenger. I actually talked a bit with Drew about it after he mentioned that it is still a factor on his car even with a lowered frontend and spoiler.

Picked up a 1:18 scale model today, and am going to start cutting and such, and rigging our flowbench to do a few crude studies.

My main goal is to improve the brick of a frontend without destroying the looks of the car. To this end, I thought of:

Taking out the inner headlights and diverting air from there and part of the grille up through the hood to force the front end down.

Doing something with the rear of the engine compartment, such as lowering the cowl, and making some ducting, to push more air out and onto the windshield rather than forcing it out the underside of the car.

I am also reading up on how diffusers work, and I'll draw something up in CAD pretty soon, hopefully.

Anyone have any thoughts?

by **ianandjess** » 04 Dec 2009 14:24

this will be a very un original car when youve done
with the corvette rear & modded body but interesting all the same
keeping the front down & still looking like a 70 challenger will be a challenge
ive toyed with the idea of a bolt on nose cone but im not going racing (well not seriously) so ill probably not bother
cheers ian

by **dave-r** » 04 Dec 2009 15:10

Well.

A 1:18 scale model is probably not big or accurate enough to the real thing to show anything worth while.

A GT40 style front end that draws air through the radiator and then up over the hood would not work unless you moved the engine back by about 3 feet.

Smoothing the side glass and making it flush to the bodywork would probably help a lot. As would a belly pan and or diffuser.

Making the nose cut the air is probably going to have the biggest effect.

Non of it is worth doing in reality.

by **Moparman1972** » 04 Dec 2009 17:22

The car is a plain jane 318. I feel no qualms about doing something different and original with it. Even if it doesn't work as planned.

As far as the front end, the battery is being shifted to the trunk and there is a small block planned now. That is going to leave plenty of room on the sides of the engine compartment for diverting air. Doing some work around the bumper/valance area will probably help as well. There's a fuel cell being sunk into the trunk floor, and due to the IRS, the exhaust must be side-exit, so it leaves room for some serious sheet metal work out to the rear valence.

The glass would be quite a bit of work. Moreso than anything else mentioned, probably. It has been done before, though. The Insidious Challenger comes to mind. Although that was all show, no function.

Even if these improvements don't make a real noticeable difference, they're a challenge, and it's something other than just bolting on restoration parts. I always love trying something new.

by **dave-r** » 04 Dec 2009 19:59

Well we will be very interested in seeing the results mate. :thumbsup:

by **Jon** » 05 Dec 2009 4:09

Go for it Man.

Imagine if good R&D were stalled by criticism. :s017:

Hell, Conestoga wagons would still be in style. :wink:

As for my ideas, diverting the air from the nose into the fenders (brakes?) and around the side of the cowl/drivers intake may be of some benefit.

by **Goldenblack440** » 07 Dec 2009 16:20

I'm always interested in aero-dynamic mods -its the smart ( but expensive) way of making them go faster and handle better. But in all reality, i really think you need a full size wind tunnel. You can actually hire them in some places -but you had better be rich to do it. These are my thoughts only...If a wind tunnel is not possible, i would be looking at many other vehicles' aero mods and see what they have done. There was an interesting one in a Mopar mag a while ago -a gold Dodge Charger '68 i think. I even saw it on ebay about 6months ago. It was a full huge dollar custom job - he had completely redesigned the front nose area to divert air around and through -not blocked up like a brick wall. He also did a fully sealed underbody (smooth). I think side ground effects can make a difference and of course well designed front and rear spoilers. But to get the most out of any mods, you need many hours in a wind tunnel or a million dollar software program. Good luck.

by **fal308** » 07 Dec 2009 16:38

Several years ago Top Fuel cars found a major airflow improvement when they rolled the fenderlips, instead of keeping them flat.
As for the flush-mount glass, you could make temporary lexan windows that would mount flush.
A big area that really traps air is the grill area. You may want to read up on the Charger 500 design and what Chrysler did to the Charger to turn out the 500 for NASCAR.

by **Moparman1972** » 08 Dec 2009 1:04

Thank you both for the tips. And for not just passing this off as bullshit.

I will try to look up that 68 Charger you spoke of.

Years ago I had a book about the design of the Charger 500, the wind tunnel testing behind the flush-mounted rear window, grille design, etc. Can't remember much of it, but I'm sure interested again!

I have a pair of Charger 500 headlight doors sitting downstairs, actually. I missed out on the rest of the grille by 2 weeks from the guy who sold them to me.

by **dave-r** » 08 Dec 2009 8:58

Was the Charger 500 not a 1969 car?

Don't confuse it with the 1970 500 as that was just a trim option.

If you flush the 1970-71 Challenger grille off flush with wire mesh you would probably see a big improvement in high speed aerodynamics and still get enough air into the grille to stop the engine overheating.

The 1972-74 Challenger is not as bad.

by **dave-r** » 08 Dec 2009 9:02

Moparman1972 wrote:Thank you both for the tips. And for not just passing this off as bullshit.

I don't think anyone would say what you are trying to do is bullshit. It is obviously of huge interest to you.

However it is a waste of time in reality.

Of course if you flush and smooth any 70s car it will improve the aerodynamics. We already know that. It is already proved in modern car design.

But the whole point of these cars is their looks. Doing stuff to one to make it smoother is just going to make it ugly.

If it is aerodynamic it is not a Challenger any more it's a Daytona.

by **Moparman1972** » 08 Dec 2009 12:05

The 68 Charger that I was talking about was the one that GoldenBlack mentioned, separate from the 1969 Charger 500.

I want to try and keep the looks of the car, which was why I wanted, if possible, to divert air behind the grille rather than change it. That would be a bigger challenge than popping a nosecone on it, and while it won't achieve the same results, I DO love my challenger's looks.

Maybe this problem doesn't come up here, but you see a lot of outlandish talk on other boards that just wastes people's time. I don't like to do that. And talking about vette rearends and aerodynamics stuff is admittedly out there for a Challenger build. So thanks!

Fal, I was trying to find information about the fender lip rolling that you mentioned, but have failed. Do you remember anything else about that?

by **dave-r** » 08 Dec 2009 12:12

How about sticking a massive twin turbo engine in there and suck all that air in through the front grille. :wink:

by **Goldenblack440** » 08 Dec 2009 14:48

Moparman1972 wrote:I want to try and keep the looks of the car, which was why I wanted, if possible, to divert air behind the grille rather than change it. That would be a bigger challenge than popping a nosecone on it

I agree!

Firstly, that bronze or gold 68 i saw - i can't rememebr if it was Mopar action or Mopar Muscle. Maybe a Google search, or on their websites search. It was a very interesting car, not least as well, the custom interior which was not stupidly custom, the Hemi (of course) engine and neat little unobtrusive custom mods, along with the redesigned front end.

Secondly, it will be much more of a challenge to do something useful with the air hitting the front, rather than just tacking on an ugly nose cone. That's what they did for the Daytona Chargers of course, but that still required a hell of a lot of testing and design.

But i think the biggest hurdle will be designing and making the test equipment to determine where exactly the air is going, and how much, and into what places, when it hits the frontal area. Just guessing would certainly lead to many hours of frustrated fabrication attempts.

You can't minimise the frontal AREA without destroying the Chal's looks, so you have to do something with the air by redirecting it. Learning some aerofoil design/Venturi Effect (aircraft wings and lift and downforce etc) would be a good start

by **dave-r** » 08 Dec 2009 15:05

Don't forget. Downforce = drag.

by **drewcrane** » 08 Dec 2009 20:37

dave-r wrote:Don't forget. Downforce = drag.

just make more power :nod:

by **fal308** » 09 Dec 2009 1:32

Don't recall the details but IIRC it was shown on John force's Funny Car (not a Top fuler as I stated above). For years the sides of FCs were slabsided, then someone did some wind tunnel testing. It was found that the area around the tires was a low pressure area and the sharp edge of the fender was creating turbulence. When they rolled thhe lip, it cut down on the turbulence.
I may not have all the details correct but that was the gist of the story. IIRC I saw the article in Hot Rod??
You may also want to check out some LSR cars for ingenuity and originality in many areas. These guys usually do more with less than anyone. This can get you started http://www.landracing.com/ They have some links to other organizations (SCTA is the big dog in LSR-they run Bonneville).
Also as others have said, don't forget things like full belly pans, spoilers etc. NACA ducts can help pull air through your engine compartment, if designed correctly.
For info and photos of a modified Challenger that has quite a few aerodynamic aids, check out www.glennbunch.com though it hasn't been updated in a couple of years now. Don't know if he's still racing or not.

by **patrick** » 09 Dec 2009 6:10

drewcrane wrote:
dave-r wrote:Don't forget. Downforce = drag.

just make more power

Glenn Bunch did. :s003:

by **Goldenblack440** » 09 Dec 2009 8:08

fal308 wrote:Don't recall the details but IIRC it was shown...[] ... IIRC I saw the article in Hot Rod??

Forgive my ignorance, but what does IIRC stand for?

I only recently worked out that IMHO is "in my honest opinion" !

by the way, some nice follow up info links there.

by **fal308** » 09 Dec 2009 15:50

Sorry - IIRC is internet shorthand for If I Remember Correctly.

by **Goldenblack440** » 09 Dec 2009 16:02

Well... IWNHWTO ! (I would never have worked that out). I have seen that a few times now. So now i know, thanks!

by **dave-r** » 09 Dec 2009 16:25

Being rather dyslexic I struggle to work some of these out myself. :oops:

by **Goldenblack440** » 09 Dec 2009 18:24

Yes, i am also a touch dixlesic. :confused:

by **Moparman1972** » 09 Dec 2009 23:39

dave-r wrote:Don't forget. Downforce = drag.

I'll take downforce over upforce.

It is going to be nigh impossible to tell what is doing what when the car goes together, because so much is being done at once. The only thing I can think of to do to measure tangible changes is to use pressure pads on mounting points for the reverse scoops in the front that would be diverting air from the inner headlights/grille. (These scoops being mounted to the body, not the hood.) Then I could possibly see how much downforce is being produced by those components. I can't see any way to measure the other changes. (Full Scale)

I could take the mythbusters route and put a scale model in a tube and flow water speckled with flakes through it! :p:

Thanks Fal for the point to those sites. Glenn sure has a unique challenger! I pulled a photo off the site of him at speed. Look at that hood flex! :shock:

by **patrick** » 10 Dec 2009 5:56

Dylan

If you haven't already done this, check the youtube stuff on Glenn Bunch. Good stuff and, the 172 MPH, 1973 Challenger track car. The picture you posted. :thumbsup:

by **Goldenblack440** » 10 Dec 2009 13:14

That's a really nice looking track car -those bolt on's compliment the shape rather than change it completely like the Daytona's did with the Charger. Wonder what it weighs? I'll have to check out You Tube and the rest now.

by **dave-r** » 10 Dec 2009 13:40

It looks like a snow shovel. :lol:

by **fal308** » 10 Dec 2009 14:02

The car resembles a Challenger less and less as it progresses. IIRC he says that the near-stock look just isn't aerodynamic enough. If you look at the photos in the later stages of the car, the sides get more rounded and the front changes also.

by **dave-r** » 10 Dec 2009 14:27

Which was my point. The more aerodynamic you make it the less it is a Challenger.

by **patrick** » 10 Dec 2009 15:24

dave-r wrote:Which was my point. The more aerodynamic you make it the less it is a Challenger.

I still want to drive it. :p: