Cold Air Intake vs Short Ram Intake: Does It Actually Make a Difference?

Intake upgrades are one of the most common first modifications on a performance build. Both cold air intakes and short ram intakes replace the factory airbox with a less restrictive setup, but they do it differently and produce different results. Understanding what each one does, where it works, and where it falls short will help you choose the right one for your car and your goals.

What Does a Factory Airbox Do?

The factory airbox on a production car is designed to balance several competing requirements. It has to flow enough air for the engine at all operating conditions, reduce noise to meet road regulations, filter out dust and debris, and do all of this reliably across a wide range of temperatures and environments.

The result is typically a long, multi-bend intake path with an enclosed filter element. On a stock engine the factory airbox flows enough air that restriction is not a problem, on a modified or tuned engine however, the factory intake starts to become a bottleneck.

What Is a Short Ram Intake?

A short ram intake replaces the factory airbox and inlet pipework with a short, straight pipe and exposed filter. The filter sits close to the engine, usually in the same general location as the factory airbox. The intake path is shorter and less restrictive, the filter is larger, and induction noise increases noticeably because the filter is no longer enclosed in a housing.

Short Ram Performance Gains

Power gains on a short ram intake are modest on most platforms. Throttle response improves because the reduced restriction allows the engine to respond more quickly to throttle inputs. Peak power gains are typically in the range of 5 to 10hp depending on the platform and how restrictive the factory intake was to begin with.

The Heat Soak Problem with Short Ram Intakes

The main drawback of a short ram intake is heat soak. The filter is commonly positioned inside the engine bay without any heat shield, which causes the intake to suck in more hot air than cold, especially after a hard run. Hot air is less dense than cool air, which means less oxygen per volume and less power. In stop-and-go traffic or after sustained hard driving, a short ram intake can deliver warmer intake air than the factory setup on many cars, particularly if the factory airbox was drawing from a cool source outside the engine bay.

What Is a Cold Air Intake?

A cold air intake typically routes the filter away from the heat of the engine bay by positioning it behind a heat shield or outside of the engine bay in the guard area where it can draw cooler air, the pipework is also typically longer than a short ram intake. Because of this the filter typically sees significantly lower air temperatures from cooler outside air being forced into the intake.

Cold Air Intake Performance Gains

The power advantage of a cold air intake over a short ram comes primarily from intake air temperature, not flow. Cooler, denser air contains more oxygen per volume, which means the engine can burn more fuel with it and produce more power. On a hot day or after extended hard driving, the difference in intake air temperature between a short ram and a cold air intake can be meaningful, and that temperature difference translates directly into power.

Short Ram vs Cold Air Intake — Key Differences

Filter Position

A short ram filter sits inside the engine bay, typically without a heat shield. A cold air intake filter is situated behind a heat shield or routed away from the engine bay to a cooler location. Filter position is the defining difference between the two designs and is what drives the difference in intake air temperature.

Intake Air Temperature

Short ram intakes are more susceptible to heat soak, particularly under low-speed or stationary conditions. Cold air intakes maintain lower intake air temperatures, especially at speed. On forced induction cars, intake air temperature directly affects how aggressive of a tune you can run. Cooler intake temps allow for more timing advance without knock, which means more power.

Installation Complexity

Short ram intakes are generally simpler to install because the filter stays in the engine bay and the pipework is short. Cold air intakes involve installing more pieces or routing a longer pipe to a lower, more remote location and can require more time to install depending on the car, though both are straightforward installs on most cars.

Power Output

On most platforms a cold air intake will produce slightly better results than a short ram because of the intake air temperature advantage. The gap is most noticeable on forced induction cars or in hot ambient conditions. On a naturally aspirated street car in mild weather the difference between the two in outright power is small & typically not noticeable.

Does an Intake Upgrade Actually Make a Difference?

On a Stock Naturally Aspirated Engine

On a stock engine, the power difference from an intake upgrade is modest. Most drivers will notice improved throttle response and a more prominent induction sound before they notice any change in power. The gains are measurable on a dyno but are unlikely to be felt in normal driving.

On a Modified or Forced Induction Engine

On a forced induction, modified engine, or any car that has been tuned, the factory intake becomes a more meaningful restriction. A cold air intake on those cars lowers intake air temperature, allows for a more aggressive tune and ultimately more power gains. Like most modifications the gains compound & become more noticeable with supporting modifications.

Which Intake Is Right for Your Car?

Short Ram Intake: Best For

A short ram intake suits a street car with a stock or mildly modified car where the priority is improved throttle response and induction noise rather than peak power. It is simpler to install, generally less expensive, and works well on most platforms.

Cold Air Intake: Best For

A cold air intake suits any forced induction car or a modified engine with supporting mods. The intake air temperature benefits compound and make a more meaningful difference, especially if money has been spent on a tune, feeding the engine warm engine bay air wastes some of that investment.

Pairing an Intake Upgrade with a Tune

An intake upgrade on a car that has been tuned almost always produces a better result than the same intake on a car still running the factory map. The ECU needs to account for the change in air temperature and flow to make the most of the modification. If the rest of the build justifies a tune, do the intake as well, rather than fitting the intake and leaving the factory map in place.