The Whats and Hows of Cold Air Intake Systems

Performance upgrades can be costly. They may also be hard to get right the first time around. Not so with air intake systems. These are inexpensive engine modifications (compared to the exorbitant cost of other upgrades, anyway) that are simple and quick to install. They modify the amount of cold air coming into the engine for combustion. And more air means a bigger bang, and more power from the crank.

What is a Cold Intake System?

Air intake systems consist of tubing and air filters that redirect air towards the engine. On stock vehicles, the tubing design and size, along with the choice of materials in the filter are hindering factors. They provide just the right amount of air to be combined with the corresponding amount of fuel, before the mixture makes its way into the cylinders. The purpose of an aftermarket cold air intake system is to increase the volume of air. And cooler air is richer in oxygen, so is more effective. Your engine gets more horsepower and torque as a result.

Why Install a Cold Air Intake?

The engine requires roughly 15 times more air than fuel in the air/fuel mix for optimal efficiency. It also needs air to be sufficiently cooler than that already in the engine. A cold air intake takes care that these two points are met.

How Does a Cold Air Intake Work?

In stock systems, outside air is cleansed and flows through a paper filter, then redirected through a complex system of tubing, before entering the combustion chamber. These are often the restricting factors that effectively deprive the engine of the amount of air it needs. Stock tubes in particular are at fault here, as they need to comply with the engine layout and available space, while also being manufactured at a certain price point.

An aftermarket system, on the other hand, makes use of all the space in the engine bay, to include wider, straighter tubing. This is also often lined with a lightweight, yet effective heat shield to deflect radiant heat from surrounding parts (particularly exhaust manifolds). With simpler, straighter designs airflow is maximised and enters the engine at optimal angles. Systems are also complemented with an airbox to redirect more of the collected air into the intake hoses in the cylinders. With modified and beefier filters, often pushed up front towards the bumpers, cleaner and cooler air is significantly increased to aid easier spooling of turbines. The result is more air, with less restriction. With the heat shield, it is also cooler, and thus the name.

What to Expect?

The benefits of an aftermarket cold air intake are manifold. Newer parts provide up to 80 per cent more air into the engine and turbos, and horsepower and torque figures increase up to 20 per cent, depending on the system and the engine. If you’re a sucker for a raspy engine note, then a modified air intake will also add more backbone to the sound. There’s also less weight involved, with lighter and stronger materials that bear better in increases in pressure and heat. Overall, the engine is less stressed, so longevity is also increased. Aftermarket parts are rated for much higher tolerances, so no need to replace filters at every scheduled service interval. Then there’s the added benefit of good looks, with many manufacturers going out of their way to make air intakes appealing to the eye, and in colours and finishes that stand out.

What to Look for

There are dozens of filter kits for your engine, though not all are the same. In fact, some may be worse than the stock variant, in effect reducing airflow, and raising temperatures. When buying, there are a few things to consider:

• Materials – Most stock or OEM systems are made of hard plastics and flimsy steel connectors. Moderately-priced systems use aluminium for the tubing, which reflects heat better while also incorporating better brackets. Upscale variants go one step further. They have carbon fibre intake ducts sitting on machined aluminium cowls, and wider housings extending into carbon fibre inlet tubing. The whole system is protected with laser-cut heat shields and heat-reflective lining.
• Filter Location – Moving the location of the filters is another factor to consider. Stock filters are often located near the intake manifold where considerable heat is generated. Aftermarket air intakes move the filter up front, to provide for cooler air, and are often aided by other modifications, like air scoops in front skirts or panels to get more air in. Materials in filters also differ, with high-end intakes featuring considerably larger cotton filters better able to cleanse incoming air of any pollutants. Some designs may have inverted filters to achieve a Venturi effect, or reduce constricted airflow by lowering pressure and increasing the speed of airflow. Dry filters help alleviate the buildup of microscopic particles that can prove detrimental to the air intake sensors that monitor the whole process.

Choosing a Cold Intake System for Your Car

Prices and designs can vary considerably and not all systems will deliver the promised boost in performance. Some may also not be complete systems, so there’s unnecessary tinkering with mixing and matching parts. Choose air intake systems that are:

1. Compatible with the Engine – Aftermarket cold air intake systems need to be designed specifically for the engine in your car. Changes in overall designs, and repositioning the filters must not impede on other engine parts.
2. Designs and Materials – Straighter tubing made of lighter yet sturdier materials will scoop more air in and channel it into the engine at higher speeds. Designs will dictate the level of restriction, which typically is the reason you’re after a new intake. Outer heat barriers help reduce air temperatures while also reflecting radiant heat.
3. Water Protection – Hydrolocking is the catastrophic seizure of pistons and connecting rods due to large amounts of water entering the cylinders. Aftermarket cold intakes need adequate protection from filtering watering out, since most scoop air is low in the vehicle. Here, a sealed filter that wicks away liquids is a simple yet efficient solution.
4. Prices and Brands – Like all car parts, you get what you pay for. Performance parts with exotic materials and high levels of engineering will see the best results, but also demand a premium. Brands can be small specialised ventures with high expertise, or mainstream, producing large quantities with limited results. Choose what your wallet dictates and enjoy the rewards.