Fender Scoop Article

[johntpr]

http://www.roadandtrack.com/motorsports/a31469/dodge-charger-daytona-scoops/

[odcics2]

http://www.roadandtrack.com/motorsports/a31469/dodge-charger-daytona-scoops/

AHA!!!   

[nascarxx29]

Good read .I tried to get contact  sometime back actual vendor Jo ad .But never got a reply which was ok
.As Hackett brass did reply about makings of the wings   http://www.hackettbrass.com/copro.htm


http://www.dodgecharger.com/forum/index.php/topic,45448.0.html

[C5X DAYTONA]

More holes in that story then just the 2 on top of the fender.         

[odcics2]

More holes in that story then just the 2 on top of the fender.         

I was just waiting for your reply!!   

[C5X DAYTONA]

Quotes from article,

Hole #1.  "but, what is the deal with those scoops? At the time, Chrysler told anyone who would listen that the scoops were for tire clearance."  

George Wallace commented that NASCAR and Ford called them extractors and so did we.  We left it at that.  Then after some time we really said what there were really there for.  


Hole  #2.  "On the street version of the Superbird, there was nothing beneath the scoops so they served no function. The street Daytona had small holes cut beneath the scoop; air could pass through them but they added no tire clearance."

The Daytona only has the holes on the street version because they didn't have enough time to have the car inspected by NASCAR with no holes on street version and then find out they had to have them.  So all fenders for the Daytona were to be made with holes..   It was a timing issue.. Not an air issue.    Chrysler asked NASCAR officials if they had to run the holes on the street car and NASCAR said they did not.  That is why the Superbird doesn't have them.  


Hole #3.  "The tire clearance story had to be told to keep NASCAR's Czar, Bill France, from deeming the cars illegal. At the time, NASCAR rules only allowed body modifications for certain situations, one of which was for tire clearance."

Same story as Hole #1.    Again, they told NASCAR it was a vent.  Nothing else.   George Wallace also made a comment about calling them extractors.   He said "what else were we going to call it?"   And laughed..


Hole  #4.  " In wind tunnel testing conducted by Chrysler during the design phase of the car, engineers tried a variety of modifications and made careful note of the effect of each modification, by itself and then in combination with the others. Nose cones were tried of varying shapes and sizes. They likewise tried out different wing setups. Somewhere along the line, they tested the effect of cutting holes in the fenders and placing air extractors over the holes."

The extractors were never tested.    The 3/8 car never had holes cut into the fenders.  There are zero test showing the extractors were ever in place.  The 3/8 car was the only Daytona put into a wind tunnel prior to production.


Hole #5. "The bulk of the design of the Daytona–and then the Superbird–was aimed at getting the air in front of the car to go over and around the car. Air that went under the car was a problem: it created a situation where the car lost traction. And the air under the car was "dirty." That is, the top and side surfaces of the car were smooth and blended together. The underside of the car was cluttered with exhaust pipes and tubing, suspension and the lower extremities of the engine. Air that went beneath the car or into the engine compartment slowed the car down. The exhausters relieved some of this pressure build-up by giving the air somewhere else to go."

True for the most part.  But, the race Daytona had a very small grill, big front spoiler to move the air to the side of the car and the fenders forward of the tire were pushed out to the outside of the tire.  Getting air under the hood was a problem for the Daytona because of such a small grill.  


Not a hole but...#6.   "One aerodynamicist told me, "The least amount of air you get underneath the car, the better off you are." Of course, at the time, the Chrysler designers insisted that the fender scoops served no purpose other than to allow for more tire clearance."  

They have been saying this for over 40 years.   And still do.  Well the guys that are still here.   They didn't want to let the cat out of the bag till time had passed.


And another not a big hole but.  #7.  "Amazingly, Chrysler even occasionally let the secret slip. While they told the press and NASCAR that the scoops provided tire clearance, the scoops were referred to as "fender cooling vents" in sales materials sent to Dodge dealers. Which was closer to the truth. But not quite."

The secret was the slip.     What are you cooling down on a street car with a hole on top the fender as far as the sales materials goes?   Not the engine.   And definitely not the brakes.  The rotors have veins pumping air and drum brakes are sealed.


Hole #8.  "Strangely, that wasn't a common complaint with other brands of cars–and if it was, why hadn't anyone else chopped holes in the tops of their fenders for tire clearance?"

They didn't have the down force the Daytona did.   Also the Daytona was such a rush they didn't have time to test a full race car to get the torsion bar set up correct to minimalize the wheel travel.  Also the lower the car sits at speed the faster the car.  The fender top was the limiting factor.   George Wallace said many times, "we knew we were close to the fender top on the Charger.  We wanted a little extra room with the right front."

[C5X DAYTONA]

More holes in that story then just the 2 on top of the fender.         

I was just waiting for your reply!!   

           I hung out with George W.  too much..   haha

[Aero426]

Regardless of the John Pointer exhauster memo, the original thought process of wanting to have the OPTION of a bulge in the top of the fender as described by Wallace, Romberg, Rathgeb still holds true.  

The description of the first generation 1968 Charger race car (even before the more radical 2 x 2) describes a tire clearance problem because the body shell was separated from the platform and channeled over the floor by one inch.     Tire clearance is also why they started using the small A body coil spring hood hinges.   I acknowledge there are other issues with tire clearance such as hitting the bottom of the hood or inside fender edge.        

Regarding the three percent (!) drag reduction claim, that is a HUGE number compared to most aero improvements which are like stacking nickels.    I still want to see it proved in the tunnel.    

[PettyMower]

And then you have these:

[Aero426]

And then you have these:

The TSB is certainly a labor operation saved on the manufacturing side.  It also serves as CYA should in case anyone on the race side called Chrysler on the fact that the holes were not present on the production car. 

[Dave Kanofsky]

I hung out with George W.  too much..   haha

I don't think that is possible.  The man was a genius, and focused it on some awesome machines.

[Aero426]

I hung out with George W.  too much..   haha

I don't think that is possible.  The man was a genius, and focused it on some awesome machines.

A great man whom we hold in the highest esteem.   

[tan top]

all interesting reading 

[odcics2]

During the 200 mph run, Fred Schrandt used a ball peen hammer to put a quite a few dents under the hood inner structure to clear the tire.
There was a bump coming out of Turn 4 that concerned them when a puff of tire smoke came out of the fender air exhauster as speeds approached the 200 mark.  The tire rubber on the hood inner let him know where to bang it in. The torsion bars used were 1.6" diameter. As seen below, the bar is bigger than the hex, and the hex is "C" Body sized.  The car was at minimum Nascar clearance: 5" oil pan to ground and 6.5" behind the left front wheel chassis rail. Front spoiler was also legal at 6.5" from the ground.
One 950 cfm Holley Dominator carb was used. The location of the spoiler aft of the nose gave the car no lift, as compared to a standard Charger's 1,200 pounds of front lift.
IF, the spoiler was located more forward, then some front end down force would have occurred, with a small penalty in drag.

[C5X DAYTONA]

I hung out with George W.  too much..   haha

I don't think that is possible.  The man was a genius, and focused it on some awesome machines.

A great man whom we hold in the highest esteem.   

I concur.  There was so much to take in from him.    George always had a great story.   And one thing with George, he did not sugar coat the story.  They were actually that good.       He would come out to the Spring Fling and sit with us and the 3/8 car.   His stories even out of the wing car realm were fantastic.  About drivers, politics, family and other vehicles he worked on.    He worked on the ram induction system and we really hit it off as I have an original Ram Induction 1960 Dodge Polara Convertible.   He would pop quizzed me like crazy on the history of the system.  So glad I was well versed in the system.  He would go into great detail the R&D of it.  Fascinating stuff to me.     

[C5X DAYTONA]

During the 200 mph run, Fred Schrandt used a ball peen hammer to put a quite a few dents under the hood inner structure to clear the tire.
There was a bump coming out of Turn 4 that concerned them when a puff of tire smoke came out of the fender air exhauster as speeds approached the 200 mark.  The tire rubber on the hood inner let him know where to bang it in. The torsion bars used were 1.6" diameter. As seen below, the bar is bigger than the hex, and the hex is "C" Body sized.  The car was at minimum Nascar clearance: 5" oil pan to ground and 6.5" behind the left front wheel chassis rail. Front spoiler was also legal at 6.5" from the ground.
One 950 cfm Holley Dominator carb was used. The location of the spoiler aft of the nose gave the car no lift, as compared to a standard Charger's 1,200 pounds of front lift.
IF, the spoiler was located more forward, then some front end down force would have occurred, with a small penalty in drag.

Was the 1.6 the biggest right T-bar they had?     I remember Daytona "track" had a big bump over the tunnel that was of concern for bottoming out.

[odcics2]

They used a 1.5 bar at Daytona. That was developed in mid 68 for the 2x2 cars (2" lowered all around, additional 2" in front, needing shaved rockers and the low breather. Also a lower bathtub style intake was developed but is sucked for flow!)

In the Circuit Car - Petty Catalog of 73-74, they list one more part number for an even larger bar!!   

[RallyeMike]

47 years later there is any factual breaking news on the subject?

[C5X DAYTONA]

They used a 1.5 bar at Daytona. That was developed in mid 68 for the 2x2 cars (2" lowered all around, additional 2" in front, needing shaved rockers and the low breather. Also a lower bathtub style intake was developed but is sucked for flow!)

In the Circuit Car - Petty Catalog of 73-74, they list one more part number for an even larger bar!!   

That is crazy.   At what point does it start eating up wheel bearings....    A friend has the Marty Robbins Magnum and brought the car out for a track day a few year back.  All that thing did was bounce down the track as if it had no suspension in it. 

[C5X DAYTONA]

47 years later there is any factual breaking news on the subject?

Factual?    Thought this was laid to rest in in the early 70s.   

[odcics2]

47 years later there is any factual breaking news on the subject?

Factual?    Thought this was laid to rest in in the early 70s.   

Only photographic, documented fact is that the tire hits the hood inner and needed more room.   

Rathgeb told me that after they got the bump fixed, the cars could have used a lighter bars up front.

[odcics2]

47 years later there is any factual breaking news on the subject?

If you move your front spoiler on your Charger all the way forward, you will cut lift in half.
If I can find the wind tunnel graphs, I'll sent it to you.   

[C5X DAYTONA]

47 years later there is any factual breaking news on the subject?

Factual?    Thought this was laid to rest in in the early 70s.   

Only photographic, documented fact is that the tire hits the hood inner and needed more room.   

Rathgeb told me that after they got the bump fixed, the cars could have used a lighter bars up front.

You want all the travel you can get without bottoming out.   Stiff suspension is not good thing on a bumpy track. 

[odcics2]

Yes, wheel travel is required for a lumpy track!  Your Magnum buddy must have a screwed up set up under that car...

[Aero426]

Yes, wheel travel is required for a lumpy track!  Your Magnum buddy must have a screwed up set up under that car...

Roll couple theory.  #cookbook