INTAKE SYSTEMS

As there is with American cars, as there is with the performance aftermarket: the "Big Three." Intake, headers, exhaust. Lets start with the intake system.

Intakes, more than any other performance aftermarket part, are the most readily available. Almost all makes and models can be outfitted with one.  Many manufacturers claim almost outrageous horsepower gains, ranging from a more believable 2-3 HP to 10-15 HP. Unless your car is equip with a garden hose for an intake pipe and stuffed with a roll of 2-ply toilet paper for a filter, than it would be very unlikely to see 10-15 HP gains (come to think about it, even if your car were equip with those things, I still doubt 10-15 HP). Many would agree (and probably as many would disagree) with me that intakes (especially on newer cars) represent a more aesthetic upgrade rather than a performance oriented one. The following is an article from HCI (Hot Compact & Imports) Magazine, October/November Issue:

HORSEPOWER FROM THIN AIR...by Alan Paradise

It seems so simple, so basic. Move the air quicker with more volume into the intake system and greater performance can be realized. Nearly every performance freak and gear head longs for more power. Sometimes we go to extremes by installing massive turbochargers or supercharger kits. For the most part, the costs of these kits can be a bit too steep for the average, hard working guy. However, there is a low cost forced air induction method to gain as much as 12 horsepower...horsepower from thin air.

What you want from a performance air induction system is the ability to increase airflow capacity, airflow velocity, and deliver colder air to the throttle body. In most late model compacts, particularly Honda and Acura models, the factory air intake system can be fairly sufficient. However, when asked to perform at higher engine rpm over extended periods of time, that's when the stock air intake begins to show its downside. The big, bulky airbox prevents mass airflow and the plastic tubing can be restrictive. The location of the inlet, in more recent models, is well positioned to grab cooler outside air. Delivering cool air to the throttle body is the function of any air induction system, factory or aftermarket.

Over the past few years hundreds of aftermarket air induction systems have been developed. With all these new products, air intake systems are now the best identified in three types: short pipe, long pipe, and competition. All of these systems will deliver more air flow capacity. Two allow for cooler air flow. All three look better than the factory air system. So, which one is best for your car?

No short pipe system is actually a cold air system. These are more accurately defined as performace air intakes. On average, most inline four-cylinder engines will gain three to five horsepower from a short pipe. This is because short pipes draw air from within the engine compartment. Gaining more horsepower from these systems is not always possible. Most short pipe systems are make from three-inch pipes and fitted with a popular style air filter element. While more air flow capacity is a good thing, this effect can be countered by the inlet air temperatures. 

Perhaps more important than air capacity is air velocity. The faster the air moves from the filter element to the throttle body, the less heat is absorbed and retained. This is especially critical in short pipe systems. Long pipe systems reflect a true cold air induction system. These are intakes that are designed to force air from outside the engine compartment into the throttle body. However, long pipe systems have a greater installation difficulty. Some systems ever require modifying the inner fender wells or grill areas. Others are designed to fit neatly between the radiator mountings and headlight buckets, routing down under the car to a place where cooler air can be captured. As mentioned, the engine compartment gets extremely hot, thus air must be kept moving at a rapid pace as to not absorb heat. 

There are many true long pipe systems on the market. Some feature a molded pipe with a funnel effect to speed up air velocity. Others, such as AEM's Cold Air Induction product, features a heat resistant Zirconia powder coated pipe in a slightly smaller diameter, which increases airflow velocity. AEM has claimed through dyno tests to deliver substantial horsepower gains, in some cases as much as 15 horsepower.

Because long pipe systems produce measurable horsepower, the trick is to find the one unit that can supply the most horsepower. Each manufacturer has its own special theory on how one is better than another. RS Akimoto and AEM use filter elements with funnel ram devises to increase air flow velocity at the entry point. Other makers use a long K&N cone style filter with improved air capacity. 

There is also a street legal issue for both short and long pipe systems. If state or local mandates affect the registration of your compact car or truck, you may want to be sure the air intake system is C.A.R.B. certified before making the purchase. C.A.R.B. (California Air Resources Board) is the standard which most other states follow. Intakes that have passes C.A.R.B. testing and are certified with a C.A.R.B. number imprinted on the pipe.

True competition air intake systems are another category. These system range from exotic filters to further extensions of a long pipe system. Be aware that none of these systems are considered street legal. Also, remember that the presence of a competition system may require you to compete in more restrictive class at autocross and drag race events.

The most common competition systems grab air from beneath the car. This entry placement grabs air from the coolest possible place. However, you will need to take some precautions. For one, you will need a filter guard or grate to keep the filter element from getting damaged. It also makes it necessary to elevate the car to change or inspect the filter.

It is not unusual for innovative speed freaks to design special units, such as a hood induction. Better known as a hoot scoop, it grabs air from over the hood line, much like on vintage domestic muscle cars. These will require the use of a special hood or modifying a stock hood. The pipe is routed to the scoop opening where air can be rapidly forced through the filter and pipe.

Another method is to remove the headlight assembly closest to the air filter element. This will provide direct air flow into the engine compartment . A few years back Knight Engineering introduced the Iceman Ram Air System as an effective devise that replaces the right headlight assembly on selected Hondas and Acuras. This can be used to help short pipe system become more effective A molded scoop replaces the headlight. Iceman includes a screen to catch unwanted debris. This is not a street legal configuration. Running with only one headlight makes your car an easy target for law enforcement.

All in all, a good air induction system can net significant horsepower gains. For the money, this may be on of the most cost effective ways to increase horsepower for small engines.