JonW

I've looked up several conversion tables at different places on the internet, and they all calculate the 4.6 engine to be able to flow 410-450 CFM, depending on what VE and redline numbers you input into the equation.

I'm far from a physics expert, but it seems to me, that a STOCK 4.6 is not going to flow any more than 450 CFM, regardless of what size the air inlet to the engine is. It can't "digest" any more air than that. The stock MAF flows more than enough air. The opening in the stock airbox is capable of flowing more than enough air. So how does increasing the airflow beyond what the stock components provide increase performance, if the engine is only capable of using 450 CFM?

Forced induction works by pressurizing the air and forcing more of it (along with more fuel) into the engine. But in a naturally-aspirated stock engine, only as much air as the engine can use will be taken in. No more.

So, I submit that a proper CAI system provides a SMALL horsepower gain by introducing "cooler" air into the intake stream, not a greater volume of air. Oldsmobile was a pioneer of this concept back in the '60s, when they used hoses to duct air from either between the headlights or under the bumper to the air cleaner assembly. This OAI (Outside Air Induction) system was used on 400 and 455 cubic inch engines, and was good for approximately 10 horsepower. Following along the lines of this theory, it seems to me that providing a better QUALITY of air is more important than providing a larger QUANTITY of air.

With that in mind, what I intend to do is to keep my stock airbox, remove the rubber snorkel, and install a high-flow dry air filter made by AEM. The filter itself may provide no benefit over the stock filter, but I'm going with it "just because". Then I'm going to fabricate a ram air system that draws air from the lower valance area and ducts it directly to the stock airbox intake, similar to what Oldsmobile had. I believe this "cold air" system, along with a dyno tune, will provide as much, if not more, of a horsepower gain than the traditional CAI setup with conical filter. I'll know more later on this fall when I get it completed and dynoed. I may be right in my thinking and I may be wrong, but the dyno will tell.

karman

You are on the right track, but it seems like a lot of work for very little gain.
Move up north and you'll get all the cold air you want.
Its 56 degrees right now here and its the middle of August.
My car makes almost 300RWHP in this kind of weather and about 280 in hot weather.
My advice...
Get a good intake and tune. Make sure you have a good heatshield and a clear shot to the air below the intake filter.
The ductwork might gain you a couple of HP, but hardly worth the effort IMO.

JonW

I'd love to move up north. It's 100 degrees and 70% humidity here

This setup won't cost as much as a CAI, plus it will be very unique, which I like.

metroplex

Keep it stock.

karman

What ever you do ...
A good dyno tune can make sure it is safe for the engine.

kevinb120

bah, just get a good CAI tune package and enjoy life that little bit extra every day like thousands of us here do

Here's how a lot of threads go here for some reason:

POLL: Q1: brenspeed/tillman/bama cai combo; Q2: something else/other?

Results: Q1: 16542 100% positive answers; Q2: 4

next post: wow, what are you 'other' guys using?

JonW

SOMETIMES those other 4 stumble onto something brilliant. Besides, I'm not a very good lemming. And I enjoy being the offbeat guy that has something different.

kevinb120

We shall see. My bet is the cost of a dyno tune with the modified box, an additional traditional CAI purchase and another trip for a tune for the CAI that ends up under the hood.

JonW

Kevin, you may be right. But at least I'm the one out there giving it a try.