What does a cold air intake do to your car?

Question

I have a 1996 BMW 318. I want to know what exactly does a cold air intake do to the performance of the car.

Answer 1

A cold air intake is a system used to bring down the temperature of the air going into a car for the purpose of increasing the power of the internal-combustion engine. A secondary goal is to increase the appeal of a car by changing the appearance of a car's engine bay and creating an attractive intake noise. These aftermarket parts come in many different colors and many different sizes, and are an inexpensive way to increase performance.

Aftermarket company, K&N Engineering first offered air intake systems in the late 1980s. Those intakes consisted of rotationally-molded plastic intake tubes and a conical, cotton gauze air filter. In the late 1990s a proliferation of intake manufacturers such as AEM, Airaid and Volant entered the fray. In addition, oversea manufacturers imported their designs lending to the popularity of Japan domestic market (JDM) air intakes in sport compact markets. K&N and many of the other intake companies now offer intake systems in metal tube designs, allowing a greater degree of customization (the tubes can be powder-coated or painted to match a vehicle).

All cold air intakes operate on the principal of increasing the amount of oxygen available for combustion with fuel. Because cooler air has more density for a given volume, cold air intakes generally work by providing cooler air from outside the hot engine bay. However, the term "cold air intake" is often used to describe other methods of increasing oxygen to an engine, which may even increase the temperature of the air coming into an engine.

Some strategies used in designing cold-air intakes are:

increasing the diameter of the air intake, allowing increased airflow.
smoothing the interior of the intake to reduce air resistance.
providing a more direct route to the air intake.
tuning the length of the intake to provide the most airflow at certain RPMs.
using a more efficient air filter
Intake systems come in many different styles and can be constructed from plastic, metal, rubber (silicone) or composite materials (fiberglass, carbon fiber or kevlar). Due to the limited time air actually remains inside the intake tubing, the materials often do not impact a kit's ability to deliver cool air.

The most basic cold air intake replaces the stock airbox with a short metal or plastic tube leading to a conical air filter, called a Short ram air intake. The power gained by this method can vary depending on how restrictive the factory airbox is. The placement of the filter is usually directly in the engine compartment. The overall benefits depend on the specific application. Power may be lost at certain engine speeds, only to be gained at others. Because of the increased airflow and reduced covering, intake noise is usually increased. This effect is usually amplified on applications where a resonator, a part intended to reduce intake noise on some vehicles is replaced by the intake.

Better designed intakes use heat shields to isolate the air filter from the rest of the engine compartment, providing cooler air from the front or side of the engine bay. Carbon fiber can be used for the piping instead of metal, lowering weight and insulating the air from the engine bay in some cases. Carbon fiber and other advanced composites (such as Kevlar) come at significant costs and are often more aesthetic rather than functional (unless the application is a serious race vehicle).

The most extreme designs, sometimes referred to as Complete Cold Air (CCA) intakes, route air from outside the engine bay, usually from the wheel wells, front grill, or a hood scoop. The intake can be placed such that the forward motion of the car pressurises the air coming in, creating a ram-air intake. These intakes often require additional modifications and can require body modifications or replacement panels, such as a replacement "ram air-style" hood.

The best cold-air intakes are optimized for a specific engine application, providing increased airflow at ambient temperature and raising power at all engine speeds.

When using a cold air intake, there is a potential risk when driving in the rain. This is often referred to as "hydrolock", and according to the automotive portal, MODsearch: "Say it's raining cats and dogs and you're out for a spin in your car. Normally you'd love to rip through puddles without thinking twice, but because your engine is now getting air from inside your bumper you have to be careful. If your engine manages to suck up any amount of water through the intake and into the engine you will probably have little to no horsepower left. In other words, be careful." So, it is important to take the necessary precautions when using a cold air intake so you do not end up flooding your engine. This may include installing a water shield in your intake or not driving in the rain at all. It is also notable that less damage will occur from water getting in the engine on a rotary engine car, as opposed to a piston engine car.

Answer 2

On some cars it increases the rate of combustion providing a potential for an extra couple of horsepower. Unfortunately on your car, the M44 intake design pulls cool air through an extremely efficient intake design (look up www.realoem.com). If you add CAI to your car, there will be little to no improvement in horsepower or fuel efficiency because the car has a very effective design. You can debaffle your airbox or fog it and save a couple hundred dollars. Furthermore, if you add CAI to your 318 the air it will start pulling in will be hotter than the air it currently pulls in via the factory design (factory design runs hose to front of car pulling air in that isn't already heated in the engine bay).

In addition, there have been many studies on K&N type drop in filters in this model, and it actually turns out that the OEM $14.00 Mann or Mahl air filters provide more airflow than the cotton or foam type and provide greater protection. Many will debate this, but it's ultimately up to you and your preferences.

There's a forum at www.318ti.org that will address and give you more insight into upgrades that are similar to your 318i or 318is (assuming you don't have a TI).

Answer 3

This Site Might Help You.

RE:
What does a cold air intake do to your car?
I have a 1996 BMW 318. I want to know what exactly does a cold air intake do to the performance of the car.

Answer 4

I have a 2003 Nissan 350Z and I installed a cool air intake in my car, what it does is force cool air into the engine so the engine does not get to hot which aids the car in having more horsepower. They really do work well as long as you buy a good intake system. I have added 12-15 horse to my car, it may not seem like alot but you do feel it!

Answer 5

Racing a Ford Sedan here in England, the ideal track conditions were dry, warm track (30 degrees celsius or better) and stone cold air. The ecu will reset to rich the injectors as there is more air (hence oxygen) going in. We believed that a 5 degree air temperature would increase output by 2%. Combine that with new slicks and a bit of bump drafting and we could get pole position!

Answer 6

cold air intake car

Answer 7

So my teacher was just explaining to us how "cold-air" intakes complete bullshit. Why?
Because how does the air get colder buy changing filters and tubing?
The "performance" you get is from the air dampener being removed so that the air doesn t go in at a smooth rate.
if you truely want performance and colder air into the engine you need a bigger throttle body.
Physics my good people
thinner tubing means more pressure and therefore more temperature, thicker tubing means less pressure and therefore lower pressure and lower temperature.

Answer 8

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Answer 9

It improves performance because cold air has more oxygen and is therefore more combustible.

Answer 10

It feeds air to the engine for combustion..The more air the more power