Weird noise around 4k rpm
 

I noticed while driving today that around 4k rpm I can hear a slight resonating noise coming from the engine bay under partial throttle acceleration. I can alsoreplicate the noise while out of gear if I hold revs at around 4k. It's kind of hard to describe the noise. It's like a faint resonating ticking/squeal type sound of some sort. If I had to take a guess I'd say it sounded valvetrain related maybe? Not sure if this is just due to the rough reving nature of the VQ. Just wanted to see if anyone noticed anything like this, and if so is it normal

the car is weird in that the engine makes different sounds across all rev ranges and at different throttle openings...

I get a high pitched wirr at 2.5k at 1/2 - 3/4 throttle that i don't get at WOT.

To answer your question at 4k i do also get a different sound which will then change at 5.5k+.

I love it until the 5.5k+ part... that part is unpleasant so i shift...

At around 4k, this is when you get a nice sound from the stock intakes. It's a good noise to me but it sounds like that is not the case for you. Plus you said it happens when you're not in gear, can you elaborate on this more?

To me it sounds like a resonant type of noise. But it could be something airbox/tb related. If I get the car to say 4-5k rpm in 5th gear and let off, if I open the throttle slightly I can hear the noise.

Still in warranty? Stealership time!

Doesn't seem like a big issue. I'm pretty ocd with car noises, and it's a really faint noise to be honest. Dealership would probably just say it was normal anyway. Just wondering if anyone noticed something similar.

its odd. I hear all these problems but my 370Z is problemless except for the trunk lid

You can bet on that. These motors are generally noisy IMO..

Is it like a buzzing sound......kind of like a high frequency vibrating.....or friction sound? Cause I had a similar issue around 3-4K before I did my oil change. Now it's gone. However, I am having a rather unusual issue with my car, so it might be unrelated.

http://www.the370z.com/engine-drivet...nge-today.html

It's not a friction sound. If anything it is closer to a high frequency buzz. If it's any indication, I did put down 286whp and 243wtq stock on a dynojet 248c a couple of weeks ago.

I also did an oil change after break in at about 1300-1400 miles. Original oil and filter looked normal. Changed it with Nissan Ester Oil. In addition I had friends follow me in there cars to watch for any smoking from exhaust under acceleration. They all reported no smoke. One friend did have his air vents open and got a pretty good whiff of exhaust/fuel fumes come through his a/c vents heh.

I believe if the problem you are suggesting is a slight tapping noise that increases with engine RPM's, I believe I have it as well. Almost sounds like a playing card in between bicycle tire spokes, but a little more subtle? I have been told by 3 stealerships that its absolutely normal, and that its the loud injectors on this engine. Have you noticed that it doesnt happen until oil temps reach around 180-220? The only time I hear it is under normal to above average operating temps. Also, I can hear it more under load, especially if I drive by an acoustic enhancing object like a wall, drive thru or carport.

For what it's worth, I just started noticing this on my G37. I don't think it was there the whole time, but I started noticing it shortly after an oil change. ~15k miles.

Are you talking about the lower pitch sound that shows up as the revs get higher? I wonder if it has something to do with the plastic intake collector because I hear it with the HR motor as well.

I think we're talking about the same noise. It's kind of low-pitch sounding, and only happens past 4kish. It's kind of drone-ish