How a Front Air Dam Works

March 16, 2012

Learn about the aerodynamic effects of a front air dam, how and air dam differs from a splitter, and the basics of aerodynamic tuning.

Front Air Dam

A vehicle's front air dam should not be mistaken for a splitter. While both are crucial aerodynamic components of a car, they differ greatly in shape and overall function. Most cars are stock equipped with a basic front air dam and are crucial for engine cooling and high speed stability. But aftermarket bumper parts for various cars are equipped with larger openings to better assist in engine cooling and to accommodate modifications to engine induction and performance, such as intercoolers and oil coolers.

Aerodynamic Basics

The same principle that governs aerodynamics of an aircraft is applied to cars. Bernoulli's principle states that as velocity increases over a given area, there is a decrease in pressure. While velocity decreases, pressure will inversely increase. This pressure differential results in lift, which manages to let an airplane float in the sky. This design is best imagined by looking at the cross section of an airplane's wing, but looking at the design of any car on the road, you can imagine how the wind reacts to the shape of the automobile at high speeds. The top section of the car presents an increase in velocity and decreased pressure. The floor part of the car will exhibit low velocity and an increase in pressure.

The car itself is similarly shaped like a wing of an aircraft. But to achieve lift, there would have to be adequate propulsion and this principle applies the opposite to cars. Lift is harmful to a car's handling and stability at high speed. As the car gains speeds of up to 60MPH, lift is being generated under the chassis and causes the nose of the car to slightly lift off the ground. Car manufacturers spend hundreds of hours in wind tunnels to ensure proper aerodynamic efficiency at sustained high speed, and the design of the front air dam is detrimental to meeting standard specifications. 

This kind of negative effect at high speeds will affect most front wheel drive cars because traction is lost when the nose begins to show a lifting action. The front air dam will negate this effect at high speed and further assist in engine cooling and efficiency.

Front Air Dam Effects

A well-designed front air dam will keep the nose steady and pointed at the ground in high speed driving. This would give the driver more confidence to control the vehicle in sustained high speed driving environments. In the world of racing, an increment of a difference in aerodynamic tuning can spell the difference between victory and defeat.

An everyday car would also benefit from a front air dam, because the added aesthetic appeal is priceless among enthusiasts. There are a lot of aftermarket aerodynamic parts available for every model car and truck on the online market, and the designs could range from the simple to the relatively extreme.

Splitter and Front Air Dam

When the desire for proper ground effects presents itself, consider the splitter and front air dam combination to better channel the air around the car's body. The splitter is a flat piece of carbon fiber or any hard material that attaches to the lowest part of the bumper. This and a properly designed air dam are sure to provide your car with unrivaled traction at any speed.    

Related Questions and Answers

How Does Aerodynamic Tuning Improve a Car's Stability?

Auto racing teams have been using aerodynamic tuning for years to improve the performance of their cars. Indy car racing teams use a form of aero tuning known as ground effects to actually create a vacuum under the car, which is sufficient to hold the car upside down on a surface at racing speeds. A properly aerodynamically tuned car will hold the road better because the overall effect of the tuning package is to create what is known as downforce on the car, when it's driven at higher speed. The car will normally tend to lift off the road without any aero tuning. 

Where Can I Buy Aftermarket Front Bumpers?

Aftermarket front bumpers can be purchased from a number of places. Local purchases can be made from performance shops and specialty auto parts stores. The great thing about shopping locally is that you can see the part(s) before you buy them, and the associates at the store can answer questions about your specific needs. However, there are many online stores that sell a variety of parts. Some of the more popular internet stores are Bodykits Extreme, autopartsfair, 4caroption, and AUTOmotix. Online stores generally have a wider selection and more diversity in parts selections.

Do Front Bumper Covers Increase Aerodynamics?

Front bumper covers do have an effect on vehicle aerodynamics. Smoother surfaces allow air to pass over them in an unrestricted manner, decreasing the amount of drag on the vehicle. However, the biggest concern is the overall shape of the bumper cover and its ability to pass air around it. When properly made, a bumper will not only protect the vehicle during crashes, but the cover will provide air paths to reduce drag and assist in cooling the engine. In addition to cooling the engine, bumper covers will also assist in providing air flow to oil and/or transmission coolers.

Do Carbon Fiber Splitters Crack Easily?

Carbon fiber splitters and other carbon fiber products are very durable and light. However, they tend to cost more than standard thermoplastic parts. They do not crack easily, and because of this, they are usually selected when replacing standard thermoplastic parts. Carbon fiber products are made two different ways, and are either carbon fiber reinforced polymer (CFRP), or carbon fiber reinforced plastic (CRP). Commonly referred to as composites, carbon fiber products are stronger than thermoplastic and can withstand more punishment. However, if subjected to strong enough impacts, even carbon fiber products will crack.

What Is the Difference between a Front Bumper Cover and a Splitter?

A front bumper splitter is a device with a specific purpose. A splitter is an aerodynamic element that balances the distribution of downforce between the front and rear of the vehicle. Downforce is what keeps the vehicle firmly on the ground during acceleration and travel. Additionally, this force helps with vehicle stability during turning and general steering. A bumper cover is a material that is placed over the bumper and assists in maintaining the overall look of the vehicle. While a bumper cover may help in reducing drag and directing airflow for cooling, a splitter assists in vehicle performance and stability.

What Tools Are Required for Installing a Universal Front Splitter?

There are some simple tools required for the installation of a universal front splitter. Indeed, the tools needed are common and should already be a part of your tool box. The tools needed are as follows:

  • Standard hack saw blade
  • An electric or battery operated drill
  • Drill bits (from ¼-inch and larger)
  • Tape measure (or similar)
  • Allen wrench set
  • Sandpaper and sanding block
  • Krazy-glue (or similar)
  • Scribe (or similar object)
  • Poster board or cardboard (template creation)

The kit will include instructions, the splitter, and other associated materials and parts to complete the job. Remember, always fully read the instructions before performing any work.

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