What is the best way to reduce drag on a car's body?

Drag is the force that opposes the motion of a car through the air, reducing its speed and fuel efficiency. Drag depends on several factors, such as the shape, size, and surface of the car, as well as the speed and density of the air. Reducing drag can improve the performance and economy of a car, as well as its aesthetics and noise level. In this article, you will learn some of the best ways to reduce drag on a car's body, based on the principles of automotive engineering and aerodynamics.

1 Streamline the shape

One of the most effective ways to reduce drag is to streamline the shape of the car, making it more aerodynamic and smooth. This means reducing the frontal area, the cross-sectional area that faces the airflow, and minimizing the angles, edges, and gaps that create turbulence and pressure drag. For example, you can lower the hood and roof, round the corners, taper the rear end, and close the grille and the windows. Streamlining the shape can reduce the drag coefficient, a measure of how much drag a car generates, by up to 50%.

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Naveen Upadhyay

MSc in Interdisciplinary Engineering (Vehicle)
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The smoother and more streamlined the car's shape, the less it disrupts the airflow and the less energy it wastes overcoming resistance. In terms of F1, A fraction of a second can be the difference between victory and defeat. Take the example of a Red Bull racing (RB18) car, it features a low nose cone, minimizing disruption to incoming airflow by reducing the frontal area. The RB18's tight and uplifted sidepods reduces the car's width generating significant downforce while minimizing drag.The RB has a complex underfloor design with a venturi tunnel that maximize airflow through the car's underbody. This low-pressure zone creates significant downforce which the car closer to the track for improved cornering stability.

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2 Optimize the accessories

Another way to reduce drag is to optimize the accessories that are attached to the car's body, such as mirrors, spoilers, antennas, and roof racks. These accessories can increase the drag by creating more surface area, disrupting the airflow, and adding weight. To optimize them, you can choose smaller, sleeker, and more integrated designs, or remove them altogether if they are not essential. For example, you can replace the side mirrors with cameras, use a rear spoiler that reduces lift and drag, and avoid carrying unnecessary items on the roof.

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Naveen Upadhyay

MSc in Interdisciplinary Engineering (Vehicle)
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In my opinion, optimizing car accessories may seem like a minor detail, but it can significantly contribute to drag reduction and improved fuel economy, this translates to fewer trips to the gas station and potentially lower running costs for everyday commuters. Burning less fuel will have fewer CO2 emission, therefore, adoption of drag-reduction measures across everyday vehicles can contribute to a cleaner environment. For electric vehicles (EVs), reducing drag provides a longer driving range on a single charge, which is very beneficial for the EV owners. However, For everyday cars, the cost of implementing some drag-reduction features (like aerodynamic side mirrors or spoilers) might not be justified by a little better mileage.

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3 Smooth the surface

A third way to reduce drag is to smooth the surface of the car, eliminating any roughness, dirt, or defects that can increase the friction drag. Friction drag is the force that results from the contact between the air molecules and the car's surface, and it depends on the texture, material, and cleanliness of the surface. To smooth it, you can polish and wax the car regularly, use a smooth and glossy paint, and repair any scratches or dents. Smoothing the surface can reduce the friction drag by up to 10%.

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4 Lower the ride height

A fourth way to reduce drag is to lower the ride height, the distance between the car's body and the ground. Lowering the ride height can reduce the drag by decreasing the amount of air that flows underneath the car, creating less turbulence and lift. Lift is the force that pushes the car upwards, reducing its stability and traction. To lower the ride height, you can use stiffer springs, shocks, and tires, or install an adjustable suspension system. However, you should not lower it too much, as it can affect the handling, comfort, and safety of the car.

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5 Add some vents

A fifth way to reduce drag is to add some vents to the car's body, allowing the air to escape from high-pressure areas and reducing the pressure drag. Pressure drag is the force that results from the difference in pressure between the front and the rear of the car, and it depends on the shape and the flow separation of the car. To add some vents, you can use hood scoops, fender vents, or rear diffusers, which can also improve the cooling and performance of the engine and the brakes. However, you should not add too many vents, as they can increase the surface area and the friction drag of the car.

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6 Test and measure

A sixth way to reduce drag is to test and measure the effects of the changes you make to the car's body, using a wind tunnel or a computer simulation. Testing and measuring can help you evaluate the impact of each modification on the drag coefficient, the fuel consumption, and the speed of the car, as well as identify any potential problems or trade-offs. For example, you can use a wind tunnel to measure the drag force, the pressure distribution, and the airflow patterns around the car, or a computer simulation to model the aerodynamic behavior and performance of the car.

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7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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What is the best way to reduce drag on a car's body?

1

2

3

4

5

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7

1 Streamline the shape

2 Optimize the accessories

3 Smooth the surface

4 Lower the ride height

5 Add some vents

6 Test and measure

7 Here’s what else to consider

Automotive Engineering

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What is the best way to reduce drag on a car's body?

1

2

3

4

5

6

7

1 Streamline the shape

2 Optimize the accessories

3 Smooth the surface

4 Lower the ride height

5 Add some vents

6 Test and measure

7 Here’s what else to consider

Automotive Engineering

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