Race Charger Prep Rake/Angle of Attack

[71GSSDemon]

Does anyone know the rake the Charger, C500 and Daytonas were set up for on super speedways?  I know I have heard, possibly Dave Marcis and one of the Allisons, discussing cowl pressure and rake of these cars to make them work best.  Also, I know it was more than todays fairly level cars are.  Aaron Brown from the Garage Shop had some issues at Bonneville until the rake was adjusted - Allisons said there needed to be more rake to make the cars work IIRC.  Any help would be appreciated.

[71GSSDemon]

Found it. 

The wind tunnel tests were performed in two phases. Phase I testing started January 5, 1970 and continued to February 6, 1970. Phase II testing began March 2, 1970 and ended March 26, 1970. The 3/8 scale, fiberglass models were pitched through body rake angles of 0 to -3 degrees and yawed from -3 to +9 degrees. All testing was done at a freestream dynamic pressure of 40 psf (125 MPH).  The standard "G" Series car with a front spoiler and both a standard and semi-fastback greenhouse are compared to the "E" Series (1968-1969) race car in Figures 167a, 167b, 168a, 168b and 168c.

The "E" Series Daytona 500 (Charger and Charger 500 but not Daytona) is, generally, a better aerodynamic configuration than either "G" Series (1971 body style Dodge) configurations. However, the "E" Series car front lift is significantly higher (450 pounds) and the directional stability is lower (center of pressure is 2 inches further forward) than the "G" Series car.

Found the info on the 1968 1/2 Race car to be 2° rake or 4" over the wheelbase.

1969 Race cars were to be set at 1.5° with a horizontal floor pan.  Completely blocked off grill, getting the air solely from opening below bumper and 2" spoiler just ahead of the radiator support.  This reduced drag to 0.375. 

[Lifsgrt]

I'd swear I researched and found 4° nose down measured at the door sill worked best on NASCAR. I ran almost 231mph at Speed Week 2021 with this setting. Should break the record at Speed Week 2024 if the salt is good! Come on out!

[Mike DC]

           
BTW the rake angle on the Plymouth birds had to be set much higher than on the Dodge Daytonas.  The rear window plug design was more compromised on the birds (to keep the street car costs down).  They had to rake the car farther to keep the air glued to it coming over the  back of roof. 

IIRC this also caused them to shape the Superbird nosecone to point up a bit higher than the Daytona nosecone on the street cars.  On the racetrack they ended up pointed similarly, but the race birds were raked down harder.  It's same reason why you would have to re-adjust the headlights to point farther upwards if you rake the stance farther on a street car.       



What do you need to know all this for? 

If you're trying to set up a street car like a NASCAR (ride height & rake), that is not do-able without major surgery on the chassis.  You can lower the torsion bar height setting all you want but eventually the front subframe rails will hang too close to the pavement.  On the old race cars that didn't happen because those cars weren't stock unibodies at all.