Intake manifold myth?

I’ve seen a lot of people claim that certain intake manifolds are “meant for boosted motors” while others are “meant for NA motors”. I just read in Richard Holdener’s “How to Build Honda Horsepower” that:

“One of the misconceptions in the aftermarket industry is that this (he’s referring the the Venom) welded-box intake was designed for forced induction applications. The reality is (dyno-proven) that an intake (like the B16A) that offers power gains in normally aspirated form will do so with the introduction of forced induction. The presence of (boost) pressure in the manifold does not change the runner size, length, or plenum volume–all the major elements that dictate the effective rpm range of the manifold. What all this technobabble comes down to is that intake manifolds are much less normally aspirate/turbo specific than they are operating rpm specific.”

There are several graphs which back his statement up…but I can’t help but wonder why this meme is all over places like here, Honda Tech and Team Integra. Can anyone provide examples or knowledge or opinions, or any kind of input on this claim?

Nothing?

my mech that runs a 10.54 street legal civic(4th fastest on the east coast i think). says the skunk 2 is good for NA, JG is bad for NA

Did he ever say why?

didn’t care to ask, but it could just be the flow characteristics.

How do an FI motor’s air requirements differ from an NA one, then?

Originally posted by Trindol
How do an FI motor’s air requirements differ from an NA one, then?

Obviously a whole lot more air.

I see where you’re coming from, and I don’t understand myself.

the jg has a bigger plenum and shorter, fatter runners than the skunk2. the skunk 2’s longer runners and smaller plenum are geared more for the kind of rpm that your average performance street n/a car is going to see (roughly 8000 and lower on say, an LS). the jg flows a lot more air but is made to do so at a considerably higher rpm than most n/a, FI cars ever see regularly (7000-10000). n/a relies on vaccuum to suck the intake charge into the cylinders. the velocity isnt there at lower rpms with the huge jg intake and that is why it does not make good power on most n/a apps. with FI, you are cramming air into the cylinders and so this problem is alleviated for the most part. ive been debating which of these two intakes to use on my soon-to-be-turbo LS for quite some time. i think the skunk 2 would make killer hp and tq in the mid to upper ranges with a cammed LS, and would do really well in an FI app. the JG would only really be suitable for FI for said reasons. good luck.

good info, thank you