A cowl hood most often describes a complete, factory-designed automobile hood assembly. However, a hood cowl, an interchangeable term for a cowl hood, may be custom fitted to factory-installed hoods, thus making the hood a cowl hood.
The hood of an automobile, or a truck, is most often found at the front end of the vehicle, just in front of the windshield. It is a large, flat, molded piece of steel, fiberglass, or composite that can be raised to reveal the engine beneath. A cowl hood is, therefore, an automobile hood that is modified with one or more air-scoops, either protruding from, or integrated into the hood. Indeed, a “scoop” is another term for a hood cowl.
The cowl hood allows air to be forced quickly and directly into the air inducers and, in turn, into the combustion chambers. This process is often known as cowl induction. Air is a vital ingredient for proper fuel ignition in the performance of an internal combustion engine. The air is mixed with fuel in the engine’s combustion chamber, and then ignited. If no air reaches the combustion chamber, the engine will not run. The more air introduced to the chamber, the better the engine will run.
The custom fitting of a hood cowl involves a significant alteration of the hood. First, the proper size cowl must be determined. A hole is then cut in the hood to fit, exactly, the size of the cowl. The cowl is then seated over the hole, attached to the hood, and sealed to prevent air leakage.
There are several types of cowl hoods, mostly to satisfy personal taste in design and style. However, the larger the demand for air in a particular engine, the larger the cowl hood scoop ought to be. Many fuel-modified race cars mount large, ostentatious chrome cowl hoods that force massive amounts of air into the combustion chambers. Most automobile and truck hood cowls for regular road use are not so large or elaborate. They are, instead fairly subtle scoops that provide an engine with minor modifications enough additional air induction to perform at a somewhat higher peak than factory-installed engines.
Hood cowls may be manufactured of steel, fiberglass, or a composite, such as carbon fiber. Again, this is a matter of personal preference, though a steel cowl is considered the most durable. A steel cowl is also the most expensive, however, and is often much more difficult to install. The material used to manufacture the original hood is quite often the determining factor when choosing a cowl hood.