What is the difference between a cold air intake and a short ram intake?
As the name implies, a short ram intake is "short". Due to it's size, the intake pipe doesn't stretch far away from the intake manifold, so the air filter remains somewhere near the engine. A cold air intake has longer piping, and is designed to push the air filter away from the engine into an area that has colder air, hence the name cold air intake. Typically, since the cold air intake draws in cooler air it usually makes more horsepower than a short ram. However, depending on engine design, this isn't always the case, and we'll explain further below. A short ram intake is generally less expensive as well, and easier to install and service since the air filter is typically easy to see when you pop the hood. A cold air intake is longer, and places the air filter farther away, sometimes in a fender, so installation is more difficult as is service, and is usually more expensive.
Short Ram Intake
The short ram intake is generally designed to replace your stock air box. Most stock cars come with a plastic box with a plastic hose connected to the throttle body (or directly to the turbo). A performance aftermarket short ram intake typically has a hard pipe made of aluminum that replaces the stock rubber pipe, and the stock air box is replaced with a open element air filter. This generally gives you a good power increase over stock because you are replacing the restrictive air box with an open element air filter, and replacing the rubber hose (which is usually accordion like on the inside) with a smooth metal pipe. Most quality short ram intakes are calibrated through design to keep the stock air/fuel mixtures the same as stock to not throw any check engine lights. Sometimes a manufacture won't offer a cold air intake when their research shows it doesn't increase power over a short ram intake.
Cold Air Intake
A cold air intake is designed to place the air filter as far away from the hot engine as possible. Especially important when your radiator fan turns on, it will not blow the hot air into your air filter as with most short rams. Some manufactures make the cold air intake so that it places the air filter inside a fender or under a fender to try and capture as much cold air as possible. When an engine takes in colder air, it's packed with more oxygen, and creates more power. When a intake manufacture tests the intake, they test different air filter locations to see which is the coolest location. This usually creates more power over a short ram, but due to the location the air filter gets dirty faster, is harder to install, and harder to maintain when the air filter needs to be cleaned.