Who's the Baddest B/SA now?

[Andrew Hill]

Originally Posted by SSDiv6

The drag created by any car body in motion, is proportional to the square of velocity, so it is important at any speed. The force will increase as the speed increases.

Drag starts to have a noticeable effect at 10 MPH and downforce, depending on the frontal shape of the car, as early as 40 MPH.
This is not taking into consideration the rake of the body as it accelerates down the track.

Like the adage says, looks can be deceiving. Although a car may look or appear to be fast just by its looks, it does not mean it is aerodynamically efficient.

The 1998 thru 2002 Camaro are one of the most aerodynamic cars ever built. Below are the body specs:

Wheelbase

101.1

Track Width (Front)

60.7

Track Width (Rear)

60.6

Length

193.5

Width

74.1

Height

51.2

Ground clearance

4.5

Cd

.34

Below are the body specs for the Corvette:

Wheelbase

104.6

Track Width (Front)

61.9

Track Width (Rear)

62

Length

179.8

Width

73.6

Height

47.7

Ground clearance

4.0

Cd

.32

The Camaro has a shorter wheelbase and narrower body than the Corvette.

The Corvette has a lower roof height and shorter length than the Camaro.

The difference in both cars drag coefficient is only .02 which in the case of a drag car, is technically irrelevant.

So in a nutshell, the Corvette does not have an advantage over the Camaro as regards to body size or aerodynamics.

As a matter of fact, I believe that more detailed analysis will show the longer body and rear shape of the Camaro is an advantage at higher speeds and weight transfer when compared to the blunt, short rear of the Corvette.

The Corvette is significantly better aerodynamically as the frontal area on the Corvette is much smaller. Here's some info that I found a while back for 4th gen Camaro/Firebirds/C5 Corvettes:

1993-2002 Camaro/Firebird: Cd = 0.34, A = 22.0, CdA = 7.48
C5 Corvette: Cd = 0.29, A = 21.3, CdA = 6.18 (note the Z06 is higher)

A C5 is actually better than a Cobalt, and a third gen is actually better than a 4th gen. Obviously this is at stock ride height with stock wheels/tires, etc, so it would change some for a drag car. That being said, if you do the math, it's only a few hundredths difference.

[junior barns]

Originally Posted by Andrew Hill

The Corvette is significantly better aerodynamically as the frontal area on the Corvette is much smaller. Here's some info that I found a while back for 4th gen Camaro/Firebirds/C5 Corvettes:

1993-2002 Camaro/Firebird: Cd = 0.34, A = 22.0, CdA = 7.48
C5 Corvette: Cd = 0.29, A = 21.3, CdA = 6.18 (note the Z06 is higher)

A C5 is actually better than a Cobalt, and a third gen is actually better than a 4th gen. Obviously this is at stock ride height with stock wheels/tires, etc, so it would change some for a drag car. That being said, if you do the math, it's only a few hundredths difference.

And this is the reason for my post! These engines in all combos SHOULD be rated the same! Even in the GTO's! At say 130 mph on the big end at best should only be a couple hundreds between them! Andrew can you find any info on say your combo and the 1st gen Camaro and the 70 Corvette to compare the drag coefficient to these cars discussed here?

[Larry Hill]

Being an LS1 follower for years, you can stop smiling any time now Albert Lee, I believe the 346 LS1 in a Corvette is at factory horsepower of 345. If I remember correctly the flat hood cars were @ 305 hp and the fresh air cars were @ 320 hp. I could be wrong, but I always try to pay attention.

[Paradigm Shift]

In all candor, if either car is that quick - or any for that matter, it sounds like the system developed to look after unbalanced performance levels such as this should be allowed to work. Why have the AHFS in place at all? If the system is valid and effective, let it work.

[Paul Precht]

Originally Posted by Paradigm Shift

In all candor, if either car is that quick - or any for that matter, it sounds like the system developed to look after unbalanced performance levels such as this should be allowed to work. Why have the AHFS in place at all? If the system is valid and effective, let it work.

The AHFS would work a lot better if they used the 1/8 mile times.

[SSDiv6]

Originally Posted by Andrew Hill

The Corvette is significantly better aerodynamically as the frontal area on the Corvette is much smaller. Here's some info that I found a while back for 4th gen Camaro/Firebirds/C5 Corvettes:

1993-2002 Camaro/Firebird: Cd = 0.34, A = 22.0, CdA = 7.48
C5 Corvette: Cd = 0.29, A = 21.3, CdA = 6.18 (note the Z06 is higher)

A C5 is actually better than a Cobalt, and a third gen is actually better than a 4th gen. Obviously this is at stock ride height with stock wheels/tires, etc, so it would change some for a drag car. That being said, if you do the math, it's only a few hundredths difference.

Not trying to start an argument, nevertheless, where did you get your data? Calculations do not replace actual wind tunnel results.

The data I posted is from from actual testing done for General Motors at my former employer's wind tunnel.

Although General Motors has its own wind tunnel, it was not available to the public or racing teams until 2009. Prior to 2009, GM contracted the wind tunnel testing with outside vendors.

This is the same wind tunnel were Warren Johnson tested his new Pro Stock Firebird late 1998 and ended changing the shape of the quarter panels and rake of the car.

When he showed up at Pomona in 1999, he had to redo the quarter panels with a hammer on his car after he was protested by others and eventually Rick Jones re-skinned the quarter panels to the likes of NHRA. It is the same wind tunnel were Warren learned first hand how much drag and horsepower penalty is on a hood scoop.

[Paradigm Shift]

If all else was equal, I'll take the 7-10% reduction in drag coefficient.


Interesting comment regarding the hood scoop. I did the calculations on many Super Class scoop designs and determined the cars would be faster with the scoop reversed or no scoop at all. One racer even admitted that was the case based on his testing but thought it looked cool so he left it as-is.

Hold a flat palm out the window at 60, 70 or 100 mph and you'll quickly see how much force is applied. It certainly eats power.

[SSDiv6]

Originally Posted by Paradigm Shift

If all else was equal, I'll take the 7-10% reduction in drag coefficient.

Interesting comment regarding the hood scoop. I did the calculations on many Super Class scoop designs and determined the cars would be faster with the scoop reversed or no scoop at all. One racer even admitted that was the case based on his testing but thought it looked cool so he left it as-is.

Hold a flat palm out the window at 60, 70 or 100 mph and you'll quickly see how much force is applied. It certainly eats power.

You are correct, many years ago when I lived and worked in Reno, Nevada, one of my friends was the pilot for the Dago Red P-51 Mustang race airplane. When they modified the under fuselage scoop that cools the radiator to a smaller and more aerodynamic scoop, almost half the size, the airplane picked up an additional 18 MPH with no other changes due to the drag reduction.

In a race car, in addition to the drag based on the drag coefficient number of the particular body, you have to deal with two other issues; lift and ground effects.

In an airplane, the ground effect only occurs while accelerating during take-off and decelerating during the landing, with drag effecting the most during the takeoff. There is no ground effects after level flight and lift is zero.

However, in a race car, you have both the lift and ground effects influencing the car during the whole run and also having an impact on the acceleration and handling of the car. Then add a big scoop to the hood and now you have another additional item effecting the performance of the vehicle.

[Stewart Way]

Please explain how a plane stays in level flight with zero lift. Would think it would need lift equal to its weight.

[SSDiv6]

Originally Posted by Stewart Way

Please explain how a plane stays in level flight with zero lift. Would think it would need lift equal to its weight.

There are four forces that keep the airplane; thrust, weight, lift and drag.

Thrust, like any other object, keeps and maintains the forward motion.

Weight maintains the center of gravity or the center of mass so the airplane can fly as close to level as its design, minimizing the aircraft controls input. Its correlation is to thrust for its forward motion.

Drag, as any other object in motion is always there and the airplane, like any other vehicle, is designed to reduce the drag by reducing its footprint or coefficient of drag.

Lift is dependent of the airflow around the object as it moves forward due to thrust. There are other variables such as the shape of the object and weight. In the case of an airplane, the air moves around the wings give and maintain the airplane lift.

Zero lift is a term used in flight dynamics science in which during level flight there is an equilibrium of the yaw, pitch and roll axis during flight which is also known as leveled wings or Zero bank angle. In this configuration, the forces are balanced for optimum aircraft performance and operation.