Is it considered cold air intake?

Question

Hi i have a 97 jetta and is wat i did considered cold air intake or wat is it. I took the stock box out and added a high performance filter then i ran an air duct tube from the other side of the filter and ran it down so it sucks the air from the ground. Any answers would be greatly appreciated.

Answer 1

Don't expect any real performance improvements from a cold air intake.  They are just eye candy.  They may possibly flow air a little better, but no gains are from cold air.  Here’s why.

First, you need to think of your engine as an air pump.  If your 2.0 liter engine had the perfect cylinder heads, perfect camshafts, largest possible valves, perfect intake manifold, at 5400 RPM, it can only flow about 190 CFM of air.  I doubt you have these perfect engine components, so the engine flows considerably less, as much as 25% less.  It's not as though you are feeding a big block V8 with a big Holley carburetor.  So how much airflow do you really need?

Next, you need to examine the throttle body and the tube that connects it to the air filter housing.  I will use my car as an example.  The engine is a common multi port fuel injected, 3.1 liter V6.  On this engine, if you measure the diameter of the throttle plate, it is 2.035 inches (52 millimeters).  If you measure the diameter if the stock pipe that connects the throttle body to the air filter housing, it is 3 inches, (76 millimeters).  Since the stock pipe connecting the throttle body to the air filter is already 50% larger than the throttle plate, adding an even larger pipe will not flow any more air than can already pass through the throttle bore.  No real improvements here unless you also add a larger throttle body and enlarge the throttle opening in the intake manifold.

If you examine the air filter housing you will see that it draws its air from an opening in the radiator core support, drawing air from in front of the engine compartment.  This air is already relatively cool.  No gains found here.

The name "Cold Air Intake" is very misleading. On a cold air intake, even if it has some kind of intercooler, it will NOT cool the air any cooler than the ambient outside air temperature.  Also consider that the air passes quickly between the air filter and the throttle body, too quickly to absorb any significant amount of heat.  With a V8 engine, you gain about 1 horsepower for every 10 degrees Fahrenheit drop in temperature.  Therefore, even if you could drop the incoming air 50 degrees, you gain a measly 5 horsepower.  These gains are proportionately less on smaller 4 or 6 cylinder engines.  So they are hardly worth the expense.

Another thing to consider is that your engine is equipped with an EGR (Exhaust Gas Recirculation) valve.  This device dumps hot exhaust gas from the exhaust manifold, into the intake manifold.  This exhaust gas is over 1000 degrees F. A cold air intake can't make a difference over this extremely hot gas.  Your engine is tuned to operate with this so it is not a problem.

The air filter used in the cold air intake is the only component that may give you any real improvement.  But with a late model fuel injected engine, avoid the ones that use the washable oiled gauze elements.  If even the slightest amount of oil from the filter gets on your Mass Airflow Sensor, it will foul the sensor.  This sensor is located in the tube between the throttle body and the air filter housing.  If fouled, it will send erratic signals to the engine management computer.  This will mess up your fuel / air mixture to the point that you could have even less power than you had before you added this component.  If you already have one of these types of oiled air filter elements, you should clean the Mass Airflow Sensor with the correct cleaner every few months.  Use Mass Airflow Sensor cleaner, and not carburetor cleaner, or you will destroy the sensor.

Instead of the cold air intake, I would just simply add a low restriction air filter element.

Answer 2

I wouldn't call it a cold air intake.

It is more free flowing which is totally a plus, along with the cooler air coming into the airbox.

A real cold air intake seals with the hood, and does not allow heated air from the engine to get into the intake!

What you did is fine though :)

Answer 3

watch out for rainy days.  

Answer 4

you won't have the same affect as a true cold air intake, but it could help a little.  

the point of a cold air intake is that it is scooping up ambient air instead of the extremely hot air that is inside the engine compartment.  the theory is that the cooler air is denser giving you more oxygen to burn in any given amount of air that comes in.

do they work?  maybe.  it depends on the car, and much on the maker.  they will increase the amount of oxygen available to your car, wether or not your car can take advantage of that extra oxygen depends on the amount of air the car was getting to begin with (it may already be maxed out) and the programming of the computer that controls your mix ratios.  on some cars they will actually decrease your feul economy and power as the computer is thrown off...

after 6 years of running hi flow filters on cars, i average about a 6% increase in fuel economy.  at todays gas price that means i pay for a filter in about 3 months.