Of all the products we have tested over the past two decades, few
has yielded more bang for the buck for fuel injected engines than
the new air velocity intake systems. Actually, we were shocked.
Usually when we hear a company claim “instant bolt-on
performance for very little money”, we discover that actual
horsepower gain is either negligent or nonexistent. “But on
the engine dyno, we have proven a significant increase in power
by using our product”. I don’t know about you, but I
find that my engine is more useful in my car than it is sitting
on a dyno stand. With some clever tweaking behind the doors of a
sterile dyno lab, you could probably prove that adding dirt to
your oil will result in a power increase. And sometimes when a
company claims there is a significant gain in power by using
their product, the small print may reveal that it is only under
certain conditions, for instance at very high RPMs using 100
octane gas. But in the real world with the engine actually in
your car and hooked up to the alternator, cooling fan, power
steering, etc., a better test would be how much of this
“increased horsepower” makes it’s way to the drive
wheels. Frankly, when it comes to product claims of “more
power”, we have been disappointed more than we have been
pleasantly surprised. But not in this case.
We had to check the dyno several times to make sure that the numbers we were reading were correct. We double checked our baselines, installed and tested the intake systems, then removed them, restored the cars to stock then retested the baselines. The result: we were blown away. A 4-6% increase in real horsepower was achieved by using a product that costs less than $200 and takes only minutes to install. And this increase was consistent all along the torque curve, not just above 7,000 RPMs. So why do these systems work so well? The main reason is not that these products are highly advanced technological marvels. It’s mostly that the stock intake systems they replace suck (or should we say restrictive and inefficient).
But why do the automobile manufacturers make their stock intake systems so restrictive? The answer could be less intake noise, longer life for the engines, lower insurance rates for consumers, more business for the factory replacement air filter market, who knows? After all, an engine is just a fancy air pump. Since most stock systems are restrictive, simply increasing the air flow into the engine will help it breathe better and will usually give you better performance. Sometimes however, the vehicle’s computer doesn’t know how to manage this increased surge of air and will unsuccessfully try to compensate, resulting in a loss of power. This instance, thankfully, is not the common experience. So why should you spend money on one of these systems when you could just rip out the existing air filter and box, and put a sock over the remaining plastic intake tube. Wouldn’t that serve the same purpose? Yes and no.
Usually, anything you do to help the stock system flow better will help. Simply replacing the stock air filter with a freer flowing K&N filter (or removing the filter altogether) will often net a couple of horsepower. But you have to understand the theories of velocity, turbulence and air flow to see why the old “sock over the tube” deal won’t give you what these tuned systems offer. Ed Chang at Twin Cam Motorsports (manufacturer of the “Air Accelerator”) explains that these units work much like a velocity stack on a racing carburetor. When air entering the engine is flowing smoothly and consistently, it can be mixed more uniformly with fuel, allowing for better performance across all cylinders. These aftermarket intake systems also decrease turbulence while increasing the velocity of the air (sometimes as much a two-fold) on its way to the injection system. The old “sock” can’t do either of these things. The only system that was slightly different than the others was the unit from Advanced Engine Management, which is a cold air induction system. The others draw both warm and cold air. The warm air is drawn from inside the engine compartment, and the cold air enters the intake through the stock inlet tube located adjacent to the headlamp assembly. The cold air flow obviously increases as the vehicle accelerates, however there is no proof that it increases horsepower more than the "warm air" intakes as we were not able to test the cold air systems on a moving vehicle. So which one of these systems should you buy? Depending on your car, you may have several choices. It could boil down to a matter of individual preference, price, looks, color, whatever. We routinely use a number of these systems on both our daily driver and racing vehicles. The bottom line: you really can’t go wrong with any of these products.
- Specific applications for your Import car are discussed in each of the Performance Handbooks listed on the main page -