I was curious about this in my '97 I30 (but never enough to ask about it until after I sold it....)

There's OEM air plumbing attached to the intake before air gets to the filter. This plumbing goes to a box that has only a small hole in the bottom (for water exit?). I removed the box long ago and the car had no performance gain or loss. The box mounts close to the radiator and is positioned below the level of the battery tray. It is empty and square and made of the same material as the intake.

(My guess is that it serves to pre heat air entering combustion on cold starts.)

Any ideas? Thanks in advance for your response...

I never put it back on even when it sold but saw it in the garage this week and thought I'd ask if anyone can tell me what the box was & what function it had. If it was really important, I'll contact the person that bought it and provide it...

It is water drainage and its also a further noise reducer. Infiniti really wanted this car quiet. Its really unnecessary. I have mine removed as well.

its better if u can show the pic..

+1 It's a resonator to reduce the intake noise.

Cool. Thanks!

I miss that sort of fast & knowledgable response in the M45 forum I use now.

Unfortunately, due to the small production numbers, I doubt it will ever achieve the base of information gathered here.

Thanks again gents.