I'm suspicious that the cross-sectional area into the airbox (stock) is probably undersized for the F20 at WOT and near redline. Know enough to make a mathematical assessment?

Right now I'm leaning towards the Spoon piece, or a "Todd's Garage" rip-off. Some aluminum scrap and fiberglass, anyone?

 

I would have guessed Honda was in the best position to do that and did.. the box is pretty elaborate and I can't believe it is all noise control and they skipped WOT optimization. It appears that when integrated the design just didn

 

Great discussion.

Any thoughts on the original intention of the internal baffle with the stock air box?

Noise reduction?
Particle seperator?
Magical turbulence effector?
Stiffener for the airbox?

 

To see if the stock airbox opening (or intake tract in general) is undersized I'd like to take some airbox pressure readings underway. A friend and I are trying to figure out the best and most precise way we can do this for the least money. If vacuum in the airbox builds as rpm increases, then we probably have room for improvement just in flow.

Doing a back of the envelope calculation, the stock airbox opening is about 10" square. Or, about 65 cm^2.

We know that our engine is operating around 100% efficiency or higher in the 6000-8000 rpm range (its probably closer to 110%, but 100 is easier for now). So that means we need to induct 1000 cc every revolution. At 8500 rpm, that means we need to induct about 142,000 cc per second. That means that our approximate velocity through the airbox inlet must be equal to 2200 cm/second, or about 22 m/s. That's not an overly high speed, but I don't know what a "good" airbox inlet speed is. I do know that if you're not concerned about inertia filling, then a lower speed is better.

UL

 

Maybe I am being naive, but has anyone just tried removing the plastic right angle duct in the airbox? Would this be equivilent to leaving the top off?

I did it and haven't noticed a performance difference. It does, however, seem to run and idle "smoother". Any thoughts from the tech gurus out there?

 

Considered it, but haven't tried it. On one hand, getting rid of bends tends to improve airflow. On the other hand, the air is going to have to turn anyways to get to the filter and intake tube, so maybe bending the flow to exactly where you want it is a good idea.

It wouldn't be the same as removing the lid though because you're still shielded from hot air.

In the end, only testing would really tell if it is beneficial or not.

UL

 

[QUOTE]Originally posted by ultimate lurker
[B]To see if the stock airbox opening (or intake tract in general) is undersized I'd like to take some airbox pressure readings underway.

 

aem will have a cai out for the s2k in approx 8-12 weeks
its a wait but i think well worth it
the tube will go directly into the fenderwell
just like other cai from aem
worth waiting for

just me $.02

-jonas

 

Good idea Al. The only thing I'm concerned about it trying to read it at speed. The car vibrates and moves around enough, and we're probably looking at vacuum in the -10 to -20 mb, or well under 1" of water. Also, since a manometer is a differential pressure tool, I'm concerned about cockpit air pressure as well (is it higher or lower than ambient at speed?).

UL

 

Hey UL, dunno if this will help you any, but if you ever want to come out to my neck of the woods out here in Riverside, Huseman (sp?) performance has a flowbench.