'94 Accord Intake Air Resonance

Does anyone know of a way to mute (muffle?) the loud intake air
resonance of a '94 Accord LX Wagon?

I've used a microphone and determined the noise I'm hearing is intake
air resonance. The noise enters the cabin largely through the
windshield, but also through the doors and upper portion of the
firewall. I've insulated the hood and doors, but I'm looking for even
more attenuation.

I theorize I could design something with PVC with a movable plunger
that could introduce an echo. If positioned correctly, it should
cancel out much of the noise. It would be a "T" with the plunger
directly opposite the intake with the path to the air cleaner off at a
right angle.

A muffler attached to the intake side might work since the frequencies
are exactly the same on intake and exhaust. The cooler denser intake
air should mean there would be even less obstruction than if it was
used on the exhaust.

Even so, I'm willing to put up with a minor decrease in power to
decrease noise.

Thanks in advance for your help!

 

does it have the original intake?

i know my 98 civic has a big airbox near the fender with baffles and
different air tubes, and im sure its all well designed for
anti-resonance. dunno if something like that would fit an older accord.

 

Yes, original intake. Later model Accords got a fancier intake with
some sort of gate.

 

later meaning model change? or revision? anything up to and including
1997 stuff should work, if they changed the design since 94. i think.

 

almost any change will detune it?

Mark

 

Yea, that's the problem. I tried plugging up the two goofy PVC
expansion containers hanging off the rubber intake tube. It quieted
things down a bit, but noticably reduced low-end power.

Shouldn't introducing a cancelling wave via echo produce better
performance? You'd think the intake would do better with constant air
pressure than the peaks and valleys causing the resonance. Unless, of
course, it is desinged to time those peaks so pressure is high when the
intake valves open.

Some time after '94 Honda added a gate to the intake designed to kick
in at a certain RPM. My Chilton manual shows it. I've considered
swapping mine out with a '97 model, but a friend's '96 Accord LX is
still pretty bad under acceleration.

An '06 I test drove was nice and quiet with decent power. Too bad
handling doesn't feel as crisp and quick as my '94.

 

I don't really understand what you are saying...

the resonance can only align the peaks and valleys etc at one
particular RPM...

if you detune the box so it is quiet , it might effect perfromance at
that one particular RPM only???

No??

Mark

 

Good points, but if this method only provides attenuation of one
frequency, how does a muffler work? I'm hoping the "echo" will be a
sort of shock absorber for the intake side, which hopefully will reduce
the noise.