Aftermarket Intake Systems
Aftermarket intake systems inundate the market place and is usually one of the first “performance”upgrades that are installed. The premise of intake systems is to allow additional non-restricted airflow into the motor over what the factory intake can provide (either by design or intent). Below is an overview of intake options which are available to the consumer.
Cold Air Intake (CAI)
A CAI is a system used to bring down the temperature of the air going into an engine for the purpose of increasing power output as cooler air has more density for a given volume. A CAI generally works by introducing cooler air from outside, thus avoiding the consumption of heated air within the 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.
With the use of a (CAI) during driving in wet conditions, there may be the possibility of sucking up water due to the location of most filters for the CAI, which is usually inside of the fender well lining or mounted low within the engine bay. On the brighter side there are optional bypass valves, which is a filtered spacer that is positioned higher on the intake assembly, which may be installed. A bypass valve can prevent hydro-locking by providing an alternate route for air to come in (path of least resistance), thus eliminating the vacuum that causes water to be sucked in from a deep puddle or hole. Air only enters if the valve is sucked open as result of the vacuum pressure caused by a blocked filter at the bottom of the intake. When it comes to cold air intakes this is the “best of both worlds”.
Warm Air Intake (WAI)
A WAI is also a system used to increase the amount of the air going into a car for the purpose of increasing power output. A WAI operates on the same principal as the CAI, but the air is pulled from inside the engine bay as opposed to air taken from the restrictive Original Manufactures Equipment (OEM) air box. There is usually less likelihood of the WAI sucking up any water based on its location.It is safe to say most WAI systems will make less power than a CAI system due to the fact it is sucking in air from the hot engine bay.There are two versions of WAI.One is a Short Ram Intake system (SRI) and the other is a Long Ram Intake system (LRI).The SRI uses a short pipe with the filter itself sitting on the top of the engine bay while a LRI uses a longer tube for positioning the filter further away in order to potentially allow for a quasi-CAI configuration as it may have the capability to pull in somewhat cooler air. LRI intakes could suffer hydro-lock due to water as well if they are positioned low so you may want to consider a bypass if this is the case.
When is a CAI really a WAI?
Manufacturers usually call their aftermarket intake systems a CAI regardless of whether it is pulling in cooler air or not. This applies to Short Ram Intakes as well as Long Ram Intakes. A true CAI willhave a path to direct outside airflow whereas a WAI does not. Products like the Injen cold air intakes ystem are usually not true CAI’s as they are mounted near the radiator in some applications, thus there is usually no direct-air path to them. In these instances they are more of a WAI or a Quasi-CAI as the air temperature may be somewhat better than the location of a WAI. This is debatable.
Ram Air:The Myth?
Ram-air is a term that was initially made popular in the 60’s Muscle Car era.In effect, it was a method for pulling in outside air directly into the carburetor instead of having the vehicle utilize warmer air under the hood, thus more horsepower potential. The use of the term “Ram Air” can be miss-perceived with an assumption that these systems actually have the capability to force more air into the motor in order to increase performance.This is an incorrect assumption.Ram Air is simply a true CAI in that it has the ability to directly pull in outside air.The only real forms of forcing more air into an engine revolve around turbo and supercharger systems.
Both systems will produce a different sound and may even give the impression they are actually making more power. Most systems are inexpensive and easy to install, even for those with no mechanical background. Just do some research on the particular system you wish to purchase and don’t believe all the hype of dyno proven results the manufacturer reports.
Article By:Michael (RED_DET), NICOclub.com techie and Nissan Enthusiast