Custom CAI
 

I think this is a good idea, but before I do it I'd like opinions from those knowledgeable on this subject. I've bought some 3"mandrel bent tubing and couplings and am ready to hack away.

The plan on an FC 13b NA.... run a 3" mandrel bent pipe from the AFM (with adaptor) into the passenger headlight area. Seal the headlight area (headlight deleted) and put my cone filter in there. Air flow comes from a deleted FTP signal and turn signal, with the openings cleaned up. I may even add a NACA duct to the headlight cover for even more air flow.

Flame away or will this work good? I know this has been covered a million times in the 2nd Gen section but that's on street cars. This is race only.

It's no longer an ITS car, so IT rules do not apply. Building to NASA PT.

I took a magnahelic guage and measured air pressure in that area and got positive pressure with the ftp lense and the turn signal removed. That was at all speeds and rpm's up to about 150mph.

Your fuel map may change in some rpm range because you will end up with some Helmholz resonance changes in the intake system with the extra length. And you'll need to remap for the extra/colder air anyway.

Thanks John, so it sounds like this will work better than just having the filter right after the AFM for the time being? I don't want to go backwards in design. I'm currently running a FPR with stock ECU (clipped limiter) is all right now but have some decent HP numbers and curve. Over the next couple of months I will upgrade to a standalone (no idea on what yet) and may end up having the throttle body and intake manifold ported but not the motor (NASA rules point thing).

Anything that can give your engine cooler air will help. You'll just need to be sure the 3" pipe isn't choking you but I think the AFM is your current restriction. Once you go stand alone you can pitch it. Start reading about the Megasquirt right now and by the time your ready to change you'll be comfortable enough with it to save yourself a few grand.
There isn't much metal to really gain diameter in the manifold so be careful. The length of the runners is what limits your power up high in the rpm band more than anything else. The t body will give you some gains, air travels faster passed it than any other part of your car so smoothing things out helps.
Rotarygod has some good threads on manifold design and runner length, find them before you touch your manifold.

The air intake is done. The AFM will go when I go standalone (90%), for now this may be an improvement, at least I hope.

I ended up making a box out of fiberglass with an aluminum lid. The FTP and turn signals got removed and cleaned up. The box captures all air coming through the FTP and turn signal openings. Pictures below.

I am taking it to the track this week. The air is really going to be forced into the filter with the box, not sure if that will have any negative impact. Rain - I race in the rain, do you think that will be a problem?

Constructive feedback/criticism/suggestions. Thanks.

...and this is NOT SCCA ITS anymore, ITE now. Building to NASA rules instead now. I really should change my screen name!