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Do Cold Air Intakes work?

cold air intake

Aftermarket Cold air intake intake myths and legends

Cold air intake manufacturers make lots of promises. But do they really deliver on those promises or are they snake oil? If you’re looking for more fuel economy or more power by replacing your factory intake with an aftermarket cold air intake, think again. But if all you want is noise, well, a cold air intake can provide that, as long as you’re willing to deal with check engine lights and a drop in performance.

A cold air intake will NOT deliver better gas mileage than the factory intake

If you think you’re going to get more power or better gas mileage because you install a cold air intake system, it ain’t gonna happen. The CAI manufacturers have invested a ton of money to make you think their system will improve your vehicle’s performance. They obviously have a horse in the race. But you have to understand that car makers aren’t stupid. Do you really think they designed a bad intake system to reduce your gas mileage or performance? Really? When a difference of 1-mpg can make the difference between making a sale and losing one, do you think they’d take that chance with a bad design?

Aftermarket cold air intakes actually reduce performance

In fact, the opposite is true. Factory intake systems are already cold air intakedesigned to give maximum performance. First, they already take in cold air from outside the engine compartment. Cold air is more dense so you get more oxygen for a better burn.

If you follow the ductwork from the throttle body, you’ll see that your factory system is routed to a low point in the engine compartment. An aftermarket “cold” air intake won’t pull in any colder air than the factory intake already does.

Second, the ductwork is already tuned to minimize air turbulence going into the MAF sensor and the throttle body. If you change the ductwork and you screw up the factory tuning. Don’t believe me? Read this piece from the July 13, 2013 article of Brake & Front End magazine. This is a trade publication written for professional mechanics.

“Turbulence in the intake air stream can also affect MAF sensor calibration.” – Brake & Front End, July, 2013

Still don’t believe me? Watch this complete diagnosis on a Ford F-150 5.4 fitted with a CAI. It’s an 18-min. video and all the owner’s problems come down to the CAI with poor laminar flow across the MAF from crummy design on aftermarket air intake.

cold air intake

Here’s the important point to remember; the original equipment air filter and intake air box are specifically designed to reduce turbulence of air flowing into the MAF sensor. Replacing the original equipment air intake system with various customized intake systems can increase air turbulence and, thereby cause a calibration error resulting in an engine performance complaint.

Still don’t believe me? Read this from one of the major mass airflow sensor manufacturers:

“Mass air flow sensors require laminar airflow, which occurs when the air flows in parallel layers, with no disruption between the layers. The MAF element only samples a small part of the incoming air stream, so if laminar flow is not present, the air measurement and fuel delivery will be incorrect. Some older vehicles have a diffuser installed, but most rely on the air filter design to provide the laminar airflow.

It’s crucial to have an OE-design air filter. Some oiled filters can get over-oiled, which ends up contaminating the MAF sensor and causing worse performance.  Some cheaper replacement filters have a different design that alters the airflow direction, thus skewing the reading of the MAF.

Make sure there are no “performance” airflow devices installed in the air intake. These devices will disrupt the planar airflow that is crucial to accurate MAF readings.”

So aside from the fact that aftermarket cold air intake systems don’t provide any better power or gas mileage over the factory intake systems, they can actually decrease performance.

To understand why aftermarket cold air intake kits don’t do what they claim, see this post.

Save your money and pass on the cold air intake.


© 2012 Rick Muscoplat



Posted on by Rick Muscoplat

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