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.
A problem with short ram
air intakes is that the air entering the intake is at a higher
temperature due to the proximity of the engine, which can reduce
performance in a non-turbo engine. While in a turbo engine, the air is
cooled by the intercooler before entering the engine. Users with forced
induction engines opt for short ram intakes because compressors
adjacent to the engine, especially turbochargers, heat the incoming air
and negate much of the benefits of a cold air intake. Using the wrong
short ram intake can cause additional problems in cars utilizing a Mass
airflow sensor. Turbulence in the intake airflow produced by the filter
or piping, or a change in intake diameter at the point where the
airflow is measured can produce inaccurate airflow readings. The error
in airflow then translates to an error in the amount of added fuel. In
the worst case, the air/fuel ratio can run lean, causing detonation and
possibly engine failure. This problem can be solved by
replacing/remapping the engine control computer to provide the correct
amount of fuel for the intake airflow at all engine speeds. Choose your
short ram intake wisely....
Because a short ram
intake is located inside the engine bay, with a shorter distance for
air to travel, it creates more immediate power/torque with better
response times than a cold air.
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.
Do I need a
An air bypass valve is
designed mainly for the cold air intake. Since the air filter is placed
so low in the engine, it can suck up water when driving over a puddle
or in heavy rains. If your intake sucks in water, the engine will
likely hydro-lock, and be destroyed. A bypass valve attaches to your
intake pipe, so that if the air filter does become submerged in water,
the air will instead go to the path of least resistance, and get pulled
in through the bypass valve, and usually not suck in any water. Highly
recommended for rainy areas.
Usually a short ram
intake would be louder, since the pipe is shorter in length and closer
to the throttle body. A harmless but noticeable result of using a short
ram air intake is an increase in intake noise, which may manifest as a
sucking sound, and the loss of any silencing properties that the
factory intake had. In turbo cars, which have a turbo pressure bypass
valve, a short ram intake can produce a loud hissing sound when the
throttle is lifted at high boost. A cold air intake isn't much quieter,
but might sound a little less deep due to the air traveling a farther
distance in the pipe and the pipe almost acting as a resonator. Both
give your car a strong deep tone when on the throttle that is
undeniably a modified sound that any enthusiast recognizes.
Are air boxes
better than open element air intakes?
This really depends on
your vehicle. Some vehicles are designed in a way that places the air
filter in front of, or near the radiator. The problem with this is that
the air filter will get hot air pushed into it when the radiator fan
turns on. One way around this is to put the air filter into a box that
blocks the air from the radiator fan from directly hitting the air
filter. For vehicles with a design like this, an air box would be
better. Keep in mind also that sometimes an open element air filter
doesn't necessarily make more power than a properly designed
aftermarket air box. The air box can also keep the air filter cleaner,
requiring less maintenance.
Is it better to
have an intake with a dry air filter or an oiled air filter?
This is still debated.
Manufactures that use oiled air filters claim they capture more dirt
particles. Enthusiasts say that the oil in the air filter can get
sucked through the filter, and clog the mass air flow sensor (MAF or
MAS) and cause erratic readings. Now a days, most manufactures offer a
dry filter that does not need to have oil applied to it.
We recommend only dry
filters, and don't see any need to go with an oiled filter.