Induction Kit Review
One of the first modifications done to the Skyline is to fit an induction kit to rid the engine of the restrictive stock air box, which helps the engine breathe more easily. This is a very simple modification, and there are many different induction kits available. The next question is, "Which one is best?". This article relates to the 4 most popular kits available, being HKS, Apexi, Blitz and K & N.
What are the benefits of an Induction Kit?
The primary function of an Induction Kit is to clean the air before it enters the engine, but also to provide better air flow to improve the engines power output. The power output of an engine is proportional to the volume of air it can ingest at any given time, assuming that the fuelling is also set up correctly. The most minute restriction in the air induction system will cause an engine's optimum power output to drop. Maintaining optimum, unrestricted air flow becomes a problem when the air must pass through a filter element. There are many different designs of filters on the market, and each manufacturer will make claims that their design is more effective than their competitors. Generally, the greater the air flow restriction, the greater the power loss. Therefore, the ultimate acheivement is to choose as filter that will flow as much air as possible, witthout sacrificing filtration efficiency.
Blitz Sus Filter
The BLITZ 'Sus' Power air filters are made from T304 stainless steel which is totally unique to Blitz. The entire filtration element is made from a fine stainless steel mesh which means the filters never wear out and Blitz claim they have substantially less restriction than any other filter. Some of the other aftermarket filters are made from paper or foam elements, and some do require oiling to maintain their filtration capacity. According to Blitz, this oil gradually disperses into the inlet tracts of an engine, and coats the walls and in particular the air flow sensor, slowly reducing the performance of the vehicle. The Blitz air filters also have the same fine mesh in the top of the filter, which improves the amount of air they can flow, and because the element is 100% metallic, Blitz claim the induction note it produces is similar to a Touring car or group 'A' rally car.
Blitz Claim:
"The Blitz air filter is by far the best performing and best looking automotive air filter money can buy..."
HKS Mega Flow Filters
HKS state that engine power is directly related to the amount of air an engine can take in and expel. Therefore, one of the easiest and least expensive ways to increase the horsepower of any engine is to improve the airflow into the cylinders. However, many products in the marketplace sacrifice air filtration capability for improved air flow characteristics. HKS claim that their High Performance Air Filter Systems offer the ultimate in both air filtration and air flow for maximum engine performance. The elements use a special oil to stop unwanted dirt particles from passing through the multi-layer polyurethane filter. Filters are thrown away when their lifetime has expired and are replaced with new filters, which are inexpensive and easy to replace.
HKS Claim:
"The ultimate in both air filtration and air flow for maximum engine performance..."
Apexi Power Intake Filter
The Apexi dual funnel Power Intake has evolved from the Apexi Super Intake filter with some subtle refinements in the design and filter element. According to Apexi, this resulted in a 10% reduction in pressure drop by utilizing an upper and lower funnel. The Power Intake reduces air turbulence within the filter and creates smooth air flow into the throttle body. Maintenance is kept to a minimum as this filter is a dry-type air filter and will alleviate the problem of filter oil from "wet" air cleaners, interfering with the air-flow meter.
Apexi Claim:
"Accept No Imitations..."
K & N Filtercharger
K & N use their own unique design unlike others which use a conventional paper or foam material. K & N state that because the dirt particles are trapped inside the passages of foam or paper filters, that they eventually clog, and when this occurs, airflow restriction increases dramatically. The K & N Filtercharger uses a special cotton fabric which is sandwiched between aluminum screen wires. K & N claim that the pleated design provides five times more filtering surface over the element circumference. The filter is then saturated with an air filter oil which attracts particles of dirt and debris which build up on the outside of the filter.
K & N Claim:
"...Doubles the air flow...adds up to 15 extra horsepower..."