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Old 09-13-2001, 05:00 PM   #1
Apexboy
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Member#: 343
Join Date: Sep 1999
Location: Bellevue, Wa. US
Vehicle:
1998 Legacy GT
Granite Pearl

Default Humming from the intake.

I had a aftermarket intake, and I removed pretty much everything, and put the original plastic armor back on, except the cone. now, I am getting this weird hum when my car is on. Before I never had this problem.

Any idea?
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Old 09-13-2001, 05:29 PM   #2
whitt
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Location: Tustin
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2002 Tuxedo Bug Eye
White on white

Default aaahhhh

have you tried putting the origional filter in just to see if the sound disappears, maybe it is the sound coming through the filter being amplified by the plastic box.
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Old 09-13-2001, 06:52 PM   #3
jacobhorn
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Location: Seattle, WA Maple Leaf
Vehicle:
1998 Legacy GT LTD
'02 HD Softail Deuce

Arrow

I have the exact same sound from my intake. Sounds kinda like a vacume cleaner and it is only noticable at idle. I Removed the snorkus and the stock air box and filter and replaced it with a shielded cone filter. All other intake piping and torque reserves are still in place. I believe the noise is simply a result of the change in the harmonic resonance of air being sucked through the tubing. Essentially, by removing the snorkus and airbox, the stock sound chambers have been removed and a new air passage has been created that makes a different wound when the intake air passes through it. I think the sound is a bit annoying, but I don't know exactly how to eliminate it without replacing the stock filter and air box. I have thought about attaching some hose to the cone filter's end to see if that will change the sound. Please let me know if you figure anything out.
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Old 09-13-2001, 08:43 PM   #4
rrubel
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Location: Baltimore, MD, USA
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2008 Legacy Outback
Atlantic Blue Pearl

Default

We get the hum on our 97 GT with just a K&N panel filter. I think it's air blowing across the resonator (like blowing across a bottle) and with a different (less restrictive) filter you're just hearing more noise.
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Old 09-13-2001, 09:55 PM   #5
Patrick Olsen
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1997 Legacy 2.5GT
QuickSilver Metallic

Default

Yup, I removed just the snorkus on both my '99 and my '97, and installed a K&N in each. They both made/make the resonating noise at idle. Kind of weird, since I've never heard an Impreza make the same noise, and as far as I can tell the intake arrangement is the same.

Oh well.

Pat Olsen
'97 Legacy 2.5GT sedan
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Old 09-13-2001, 10:41 PM   #6
HIHO
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that just wooped your ass

Default

I get it too it is normal with the silencer removed.
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Old 09-14-2001, 12:01 AM   #7
remarcable
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Blue w/ Paint Chips & Mud

Default

I have normal operation with deleted snorkus. Slightly louder idle and acceleration. I also have the Amsoil filter vs. K&N filter.

But get this, last week after really pushing the car hard, I am now getting a WHISTLE at WOT. It sounds like a mini-turbo stuck under the hood somewhere.

So of course I have been flooring it all week since then.
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Old 09-14-2001, 12:02 AM   #8
pleiades
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Default

Not positive, but I think it is due to the little "air dildo's" that are on the intake piping. That or the box resonating as someone mentioned above. I didn't have that sound with my weapon R intake, but with all the other intakes I've tried/made, using the original intake hose, I have that vaccume cleaner sound. I sort of like it though.

steven
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Old 09-14-2001, 12:17 AM   #9
dvancleve
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2007 Outback XT Ltd.
Diamond Gray Metallic

Question Question

Has anyone cut off that side tube and glued something over the hole? Seems like it might slightly improve airflow and maybe it would do something about the vacuum sound cause by the snorkusectomy.

Just wondering,
Doug
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Old 09-14-2001, 12:23 AM   #10
ImprezaWRXDriver
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Traditional Blue and Gold

Default The Mini Turbo Sound

I have something like that on my Legacy, it sounds like I have a turbo that is winding up. I think that that sound is created from the extra air flow that is going into the engine. Since most of us, I am assuming, are running a K&N type air filter that the extra air passing through is causing the noise. Not entirely sure.


Gary

PS. Can anyone answer the question about the usefulness of a component in the other thread that I have started?
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Old 09-14-2001, 08:34 AM   #11
98legacygt117
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1998 Legacy GT 2.5
Red

Default phhhhhhhhhhhhh

IM gonna put in my 2 cents even though IM not sure about this. But with messing with the the intake...you coul have created a vacuum leak which would lead to that turbo charger sound. Sounds great but its going to bring down the power to the car. I dont know thatd be my guess.
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Old 09-14-2001, 08:50 AM   #12
HIHO
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that just wooped your ass

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Nope, there are no hoses loose it is just air flow into the engine. Some where it is creating a type of hum. Trust me there is no power lose in my car. I love my GT.

PS- I have noticed a slow increase in preformance. I put an exhaust and removed the silencer around the same time. I reset the CPU both times. But I feel like the computer has learned more from driving over a few weeks. Has anyone less noticed this?
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Old 09-14-2001, 09:41 AM   #13
DLC
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This is NORMAL.

Even mine has the noise at idle, going through the turbo. It's just the sound this engine makes at idle with an unsilenced intake. Now you know one reason it's there, this engine is noisy!
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Old 09-14-2001, 09:23 PM   #14
Velocity
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1998 Legacy L Wagon
Deep Sapphire Blue

Default

You pulled the "Intake Silencer", and you got a funny new noise?! Whattya expect?!?!?

Yes, my '97 GT and my '98 L both hum with the "silencer" removed. If you don't like it, don't pull it off -- it realistically only adds 1-2 hp, and that's probably an overestimate. But it sure does sound neato!
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Old 09-15-2001, 04:01 PM   #15
jacobhorn
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1998 Legacy GT LTD
'02 HD Softail Deuce

Arrow

-- Hey Matt, whats up? I'm glad to see that your still around. Have you started to mod your new Suby yet? Let me know.
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