How much does a used injen air intake for an RSX go for?

i have an 03 RSX and I have an aftermarket air intake that I want to sell. It is in good condition, I just don't know much about it so I don't even know where to begin with selling it. Thanks!

1 Answer

  • 8 years ago
    Favorite Answer

    Don't expect any real performance improvements from a cold air intake. They are just eye candy. Just a gimmick to sell you a fancy air cleaner that you don't really need. They may possibly flow air a little better, but no gains are from cold air. Here’s why they don't work.

    First, you need to think of your engine as an air pump. If your 2.0 liter engine had the perfect cylinder head, perfect camshafts, largest possible valves, perfect intake manifold, at 6500 RPM when it makes its maximum power, theoretically it can only flow about 230 CFM of air. I doubt you have these perfect engine components, so the engine flows considerably less, as much as 25% less. Realistically your engine flows more like 2000 CFM. 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? In addition, believe it or not, the factory engineers designed your stock air intake including the stock air filter to supply the engine with more than enough air. If the factory engineers wanted to restrict airflow for some strange reason, they would have simply installed a smaller throttle body.

    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 2.205 inches (56 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 nearly 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 stock 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 cylinder engines. Therefore, they are hardly worth the expense.

    Something the cold air intake fans have never explained to me. Your engine is equipped with an EGR (Exhaust Gas Recirculation) valve. This device dumps between 5% to 15% hot exhaust gas from the exhaust manifold directly into the intake manifold. This exhaust gas is over 1200 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. In general these air filters will flow a little more air than the stock paper disposable element, but only if they are routinely cleaned and oiled. If they are allowed to get dirty, they will work no better than the stock paper air filter. However, 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.

    With these higher flowing air filters, you don't notice anything until the throttle is wide open and the engine is in the higher RPM range. No real noticeable difference in normal driving. Your engine when cruising at highway speed only needs about 60 CFM.

    Personally, I hate washing and oiling air filters. A messy job. I would stay with the disposable paper air filter for this reason.

    Sell it for about 10 cents on the dollar for what you paid for it. Maybe you will find a sucker.

Still have questions? Get your answers by asking now.