"Stock Car" Aerodynamics from the early 80's

[CTX-SLPR]

Howdy,

I'm picking up a '78 Regal and I know that GM changed the nose in 1981 almost expressly for the increaced areo in NASCAR. The Regal redesign was so good that it dominated for a few years and we got the Grand National named as such to celebrate. My question is how much of an improvement is the long sloped nose Regal over the earlier short nose Regal in the more real world terms of aerodynamics? Does it show at the pump?

Thanks,

[KeithTurk]

Re: "Stock Car" Aerodynamics from the early 80's

Virtually nothing you do to the car is going to show up at the pump if you don't drive it fast every day...

Seriously wrong concept.... you can take what it cost to paint your aero project and make money by simply putting it in the tank...

Keith

[Brian Lohnes]

Re: "Stock Car" Aerodynamics from the early 80's

CTX...don't listen to Turk, the guy clearly has no idea what he's....

...wait a sec, is that a wind tunnel under his name...

Like I was saying, I'm with Turk on this one.

Brian

[Dynoroom]

Re: "Stock Car" Aerodynamics from the early 80's

Geee....... I thought it was a really bad a$$ trailer........ ;)

[CTX-SLPR]

Re: "Stock Car" Aerodynamics from the early 80's

I wasn't planning on swapping the nose for aero reasons more for stylistic reasons honestly but I thought it would be worth asking. Sounds like the older short nose on the street is worth more in terms of saving weight with the aluminum hood and shorter fenders and doors. This car started out as an idea just as a test bed vehicle but I might try to build it for mpg after I'm done with testing my V6 in it while I'm rebuilding the nailhead and getting its EFI system together.

[KeithTurk]

Re: "Stock Car" Aerodynamics from the early 80's

I gotta keep remembering your job title...

Obviously any aerodynamic advantage will decrease the required HP to drive it through the air... but below 100mph it's all pretty much a moot point unless your driving a Big Rig... then it's huge to gain a half mpg... or even a quarter of a mile per gallon...

To the rest of us... it's just on the wrong side of the decimal point...

K

[Fordplay0621]

Re: "Stock Car" Aerodynamics from the early 80's

I guess that Nose on the Daytona Charger must really help in the upper 100 MPH range. I'd like to see the Difference of the standard Charger and the Daytona Charger (Aero Numbers). I wonder if any of the Old NASCAR Guys would have any info about it?

[Huskinhano]

Re: "Stock Car" Aerodynamics from the early 80's

What about the bottom of the car? I'm sure there could be a lot done there as well to reduce drag.

[Ron Ward]

Re: "Stock Car" Aerodynamics from the early 80's

I guess that Nose on the Daytona Charger must really help in the upper 100 MPH range. I'd like to see the Difference of the standard Charger and the Daytona Charger (Aero Numbers). I wonder if any of the Old NASCAR Guys would have any info about it?

The biggest aerodynamic gain with the Charger Daytona over the standard Charger was the decrease in lift on the rear of the car by installing a flush mounted backlight. The standard Charger had a rear window that was recessed into a "tunnel" and the resulting turbulence created lift on the rear of the car. The pointed nose was an exercise in maximizing the aerodynamic advantage found in the 1969 Charger 500 which used a flush mounted grille to keep air from getting trapped in the nose of the car. (A standard 1969 Charger had a deeply recessed grille.) The big wing on the back further increased downforce on the rear tires (remember, they only used 9" tires back then!) so the car would stay planted.

[Dynoroom]

Re: "Stock Car" Aerodynamics from the early 80's

I guess that Nose on the Daytona Charger must really help in the upper 100 MPH range. I'd like to see the Difference of the standard Charger and the Daytona Charger (Aero Numbers). I wonder if any of the Old NASCAR Guys would have any info about it?

The big wing on the back further increased downforce on the rear tires (remember, they only used 9" tires back then!) so the car would stay planted.

Actually according to Bill Hancock owner of Arrow Engine Development in Michigan and a former Chrysler engineer involved in the stock car program at that time he said the rear wing was fun to play with because the other guys would come over to see what "angle of attack" they were using. Never stopping to think that the REAL REASON they were going fast was not do to the down force of the wing but those HUGE fins used to hold up that itty bitty wing. Yes the wing had some effect but it was the side fins that allowed the drivers to hang on faster through the turns.

[Fordplay0621]

Re: "Stock Car" Aerodynamics from the early 80's

Makes some sense, Aircraft have been adding winglets for years for stability and found that thier Gas milage went up to.

[CTX-SLPR]

Re: "Stock Car" Aerodynamics from the early 80's

Winglets make it more economical aswell. Winglets block spanwise flow that causes tip vorticies that cause a lot of drag. By blocking the path around the end of the wing from the high pressure bottom to the low pressure top you get more lift and less drag.

[Ron Ward]

Re: "Stock Car" Aerodynamics from the early 80's

Winglets make it more economical aswell. Winglets block spanwise flow that causes tip vorticies that cause a lot of drag. By blocking the path around the end of the wing from the high pressure bottom to the low pressure top you get more lift and less drag.

^^^^^^^^

This guy is good!

[KeithTurk]

Re: "Stock Car" Aerodynamics from the early 80's

YEP... very nice... amazing the talent on here....

So now the quesiton is why did you ask us anyway? Just to see who had a clue?

LOL this is Good... fun stuff..

Keith

[CTX-SLPR]

Re: "Stock Car" Aerodynamics from the early 80's

I wanted to know if it was a high speed aero improvement or a one that could be seen at freeway speeds. I seriously doubt all the new cars with high power and more weight than the early 80's machines get thier better economy numbers from just improved engine management. I was doubting the improvement from a brick to a slightly erroded brick but like Keith pointed out, I do deal in the minutia as a physicist.