Plenum/Air Pressure Question guys

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Feb 27, 2007 | 10:28 PM
  #1  
hey -

a local nycmaxima member had a wide open/very large/very loud cold air intake on his 3.0 maxima combined with a larger throttle body and plenum. I can't describe what it sounded like at idle...(kind of like a flying saucer????). Anyways, everyone - including a local (and completely legit) performance guru- claimed that the sound was normal.

well, I installed my crawford plenum back awhile ago - and I got that same sound at idle. no running problems whatsoever. car ran like a champ. I tightened a few bolts just a tad more and I *think* it got quieter.

anyways - the other day I installed a universal rear muffler (used to be on da mayors car - i cut off the DTM tips and painted it black). now everytime I do a WOT run - that saucer sound is extra loud (like a tea kettle) - i only hear it when I am in a tunnel tho...


what gives?
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Feb 27, 2007 | 10:36 PM
  #2  
Courtesy Pics
56k WARNING






sorry, my SLR batteries are dead
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Feb 27, 2007 | 10:43 PM
  #3  
I would have to hear the sound to take a guess.
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Feb 28, 2007 | 12:56 PM
  #4  
You only hear it when you're in a tunnel? That'd be the resonating of the sound waves from the exhaust then...no? I LIVE FOR that sound whenever I drive thru a tunnel w/ my exhaust setup...I crack or roll the windows down & drop gears so I'm in the 2500K and above range...its like music to my ears . Is that what you're referring to?
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Feb 28, 2007 | 01:02 PM
  #5  
Quote: You only hear it when you're in a tunnel? That'd be the resonating of the sound waves from the exhaust then...no? I LIVE FOR that sound whenever I drive thru a tunnel w/ my exhaust setup...I crack or roll the windows down & drop gears so I'm in the 2500K and above range...its like music to my ears . Is that what you're referring to?

yea, I only hear it echoing of high walls and passing cars (and tunnels of coarse). sounds like a tea kettle -i'll get a video

none the less, sounds very cool haha
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Feb 28, 2007 | 01:17 PM
  #6  
I love the sound of my car in underpasses and tunnels.

That has been a fun thing ever since I got my first exhaust 11 years ago.
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Feb 28, 2007 | 03:52 PM
  #7  
there are no aftermarket plenums for the 3.0 maxima that i am aware of. could he have hacked his oem up and that is causing the noise?
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Feb 28, 2007 | 03:56 PM
  #8  
That is correct. He must mean something else.

Quote: there are no aftermarket plenums for the 3.0 maxima that i am aware of. could he have hacked his oem up and that is causing the noise?
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Feb 28, 2007 | 04:00 PM
  #9  
Quote: That is correct. He must mean something else.
i was just thinking, i remember there is/was something for the 4th gen. the mevi i think they called it. i was speaking from the 5th 3.0 so maybe thats it.
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Feb 28, 2007 | 04:25 PM
  #10  
Yes, the MEVI is a variable intake manifold that was available on a few select Mid Eastern and Austrailian 1995-1999 Maximas. It allowed the VQ30 to make power all the way to the 6600rpm redline instead of choking at 5800rpms. The MEVI gained my 96 Maxima about 17whp at the peak and up to 50whp at 6600rpms vs stock (195whp@6600rpm vs 145whp@6600rpms).

I didn't notice any strange sounds though. The MEVI actually made the induction noise quite a softer due to the design of the manifold. I ran a POP style intake, CAI intake, and eventually a modified stock airbox. All the intakes resulted in slightly different sounds, but nothing like you describe. There was a very slight whistle with CAI under part throttle, but that about it. The whistle was caused by turbulant air coming across the throttle plate. Due to the lack of sound deadening with the aftermarket intake, this sound was audible. With the stock airbox in place, there was nothing.

Something tells me that this guys MEVI plenum cover is either loose or the gasket has failed and whistles under certain loads.
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Feb 28, 2007 | 05:31 PM
  #11  
Quote: Yes, the MEVI is a variable intake manifold that was available on a few select Mid Eastern and Austrailian 1995-1999 Maximas. It allowed the VQ30 to make power all the way to the 6600rpm redline instead of choking at 5800rpms. The MEVI gained my 96 Maxima about 17whp at the peak and up to 50whp at 6600rpms vs stock (195whp@6600rpm vs 145whp@6600rpms).

I didn't notice any strange sounds though. The MEVI actually made the induction noise quite a softer due to the design of the manifold. I ran a POP style intake, CAI intake, and eventually a modified stock airbox. All the intakes resulted in slightly different sounds, but nothing like you describe. There was a very slight whistle with CAI under part throttle, but that about it. The whistle was caused by turbulant air coming across the throttle plate. Due to the lack of sound deadening with the aftermarket intake, this sound was audible. With the stock airbox in place, there was nothing.

Something tells me that this guys MEVI plenum cover is either loose or the gasket has failed and whistles under certain loads.

I guess all Im getting now is that cold air intake whistle everyone raves about

ill get a video up some time this week
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Mar 19, 2007 | 04:05 PM
  #12  
alright, the whistle sound turned out to be a leak. I was one washer short, so exhaust leaked (and thus whistled) through the gaps between the washer'less bolt.


bolted up the HKS...i dun know why but the HKS gasket did not work and I had to reuse my old one
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Mar 19, 2007 | 08:19 PM
  #13  
Are there any throttle body upgrades for our cars?
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