Originally Posted by Michaelanthony2 View Post
. . . I am trying to understand how other guy always says " stock filter is able to flow X amount so no gain with anything else"
that's his opinion; in my opinion it is an oversimplification
I think it is largely based on that article that he posted -- the issues I see with that article are:
> it is based on the 2012 Boss 302 and the 2011+ Coyote intake; earlier models were not as good as those from the factory
> it is written mostly by a Ford engineer -- of course they are going to say that their stuff is the best; they want to sell cars and they don't want to open themselves up for liability by endorsing aftermarket products that could do damage if not used correctly
Many intake products are rated by CFM, for example cylinder heads and carburetors are commonly rated by CFM (cubic feet per minute, flow rate). But that is also an oversimplification. Those flow rates are based on a standard test, which uses a standard pressure drop or "suck amount" for the test. If you reduce the pressure drop (suck amount) they will flow less; if you increase the pressure drop (or suck amount) they will flow more; and the point of an intake modification is to reduce that pressure drop, so more air will flow in. If you have a filter that will flow more than you need at a certain pressure drop, if will have less pressure drop for the flow that you need, which is what you want.
In the end, you should take all of this with a grain of salt; these products rarely deliver what their marketers claim, but they are still fun; if you really want to know how much you gained, the only way to do it is to run a before and after dyno test.