CIS Induction Question

[zevenbergena]

CIS experts out there:

With my basic knowledge of induction and crude understanding of CIS, I know that the more air you get into the motor, the more gas= more power. I've seen a couple threads about supercharched SC's and of course the option of turbocharging for power, but for a normally aspirated motor I was just curious- If you were to run ducts from a NACA type intake on the rear quarters and run it back to the airbox, it would force air through the injection system at speed and should increase output? If it were to have an effect, what tuning challenges might this present with different psi hitting the intake at different speeds? Would this be something that with experimentation could be manageable or be more likely disasterous?

[Paulporsche]

If you do a search you will find this has come up many times. The general consensus is that this will not be an improvement as the amount of air entering the system is already more than the air flow sensor and plate can use.

[RarlyL8]

I actually did that with the GT2 tail on my widebody SC when it still had the 3.0L engine.
What I found was that the throttle response at speed was a touch better and the engine felt a little stronger due to cold air induction. I figure this was due to the ram air effect at speed, combined with lower ambient air temperature, reducing or eleminated the vacuum created when you crack the throttle plate wider than the small opening seen at cruise. Denser air = hp. There was no noticeable effect below ~60mph.
I wouldn't add NACA ducts just for that purpose though.

[Porsche-O-Phile]

Compression of air does not occur enough to result in appreciable changes until nearly mach number speeds. "Ram air" systems are largely just for show. They do little, if anything.

[RarlyL8]

Any gain seen will have more to do with ambient air temperatures than the ram effect.
Large air filter assemblies become heat sinks. Replacing metal with plasic and reducing the size of the housing helps reduce the heat. Forcing less hot ambient air in at speed helps cooling even more.
But again the returns for the mods are miniscule.
To directly answer your question, it won't hurt anything and no tuning is necessary.