In the literal sense, you are correct. The factory Ford Raptor intake has a sealed filter box and the inlet port draws air from the fender area. The benefits of an aftermarket "cold air" intake are larger filter surface area and less restrictive intake tubes. The intake tube material also plays a role in delivering *cool* air to the intake manifold.
maybe. but if the info in this writeup is correct than real benefits will only be realized if one is consistently running the engine at 5 or 6 thousand rpm
...... research on the intake “problem” of the Ford Raptor. Initially he thought that the intake snorkel that sucks air into the airbox from the inner fender was the restrictive factor, but he was mistaken. The interior diameter of the snorkel is greater than that of the intake hose at the air flow sensor. Changing the snorkel for something bigger will do nothing to improve the volumetric efficiency of the factory intake system. Changing the diameter of the intake hose that runs from the airbox to the throttle body will do that, but doing so will decalibrate the air flow sensor and make the computer think that the intake is flowing less air. Thus, a larger tube will create a lean air-fuel mixture that will destroy performance and might destroy the engine as well.
The Cubic Feet per Minute (CFM) requirement of an engine is calculated via the following formula:
Engine Displacement (CUI) X RPM
____________________________ X volumetric efficiency = CFM
3456
6.2L equates to 378 CUI, and the redline on the Raptor is 5,750 rpm. The volumetric efficiency of a naturally aspirated 4-stroke gas engine is 0.7 to 0.8, and the volumetric efficiency of a diesel engine is 0.9. Our hero wanted a fudge factor so he used 6,000 rpm and a volumetric efficiency of 1.0. (The Raptor has a high performance engine, so what the heck?) So….
378 CUI x 6,000 rpm
_________________ X 1.0 = 656 CFM (Without the fudge factors it calculates to 503 CFM)
3456
So, what does this tell our number crunching hero? Well, the K&N drop-in filter for the 5.4L and 6.2L engines in the Raptor (P/N 33-2385) is rated by K&N at 783.7 CFM. By a wide margin it is capable of flowing more air than the engine can process. You could put a filter as big as a suitcase on that engine and it won’t run any better than with the K&N filter with the rest of the factory intake system left on the engine. So what do you get with a bigger tube as with some aftermarket CAIs? You get an intake system that will flow more air on an engine that doesn’t need it. Will it make a difference? Yes, but primarily at very wide throttle openings. Our hero doesn’t spend much time at WOT, so there’s no incentive for him to spend a lot of money to obtain horsepower potential that he’ll never see.
There’s something else that he learned. The advantages of a big bore intake system are realized at large throttle openings and therefore high flow rates. The disadvantage is that you can have an intake system that’s big enough that air will stall inside of it when you back off the throttle. This is Not A Good Thing. The intake is necessarily a compromise. A race engine would want to be set up for performance at large throttle openings and high flow rates, but a daily driver would not benefit from such a set up because it will spend most of its life at modest throttle openings.
