Ferrari: 328 mystery noise under hard acceleration

Had been experiencing an annoying raspy/buzzy sound from my 328 ever since
my last major service 6 months ago. Sounds happens under hard acceleration
in the 4-6 KRPM range. Last month Scottsdale Ferrari investigated but was
unable to identify for sure the source--they thought maybe it was transfer
case gears and tried replacing the gear oil (no joy). Tracking down "funny
noises" is a real pain in the a$$ for auto mechanics, I sympathize.

Was poking around the car last weekend and noticed some debris in the engine
intake duct--see link below to a couple photos. I removed the majority of
the loose stuff, and have been free of the noise ever since. Being an
engineer, I was at first a bit hesitant to declare victory...but prior to
removing the debris the noise was present 100% of the time (under the stated
operation conditions) and now after a full week the noise is 100% absent.
My theory is that the loose matter happened to be just the right mass and
geometry to resonate at a certain air velocity range which is a function of
car speed and engine speed...and the shape of the duct acts like a horn to
amplify the sound coming from the vibrating debris.

http://members.cox.net/ted.adlam/328_intake1.JPG
http://members.cox.net/ted.adlam/328_intake5.JPG

Just curious if anyone else out there has run into a similar problem. What
in the world could cause chemical deterioration of the intake duct? I would
think that the material used would have been selected to be fairly
impervious to chemical attack...maybe I give Ferrari too much credit for
expertise in material science. Fortunately their engines are top notch so
I'll cut them some slack on their choice of air intake duct materials.

Regards, Ted.

"TigerRace1" <com> wrote in message
news:aol.com... 

Because I think there are some lines you just don't cross - even on usenet.
The world is screwed up enough without allowing idiots like Mikal to screw
it up even further....
 

Probably true - I don'k think there's a cat in hell's chance of us hearing a
peep out of him. In which case his ISP will hear from me.
 

Welcome.

I.