Before I installed my ARK catback, I got more sound from the intake than the exhaust. Take a look in that direction, too.

 

Try an IPL muffler. They are quieter and deeper than the oem muffler. Check the classifieds. Muffler section will bolt up to the the stocker

 

The OP is complaining of sound below 2k rpm. It seems to me deeper tone is the wrong way to go. Granted, it's something to try and he'll little trouble selling it if it isn't helpful to his sensitivity.

 

Well the IPL muffler has traditional packing vs the baffles of the stock unit so i think that will dampen the sound hes hearing

 

Might be worth investigating active noise cancellation - that is, a unit that plugs between the radio and amp/speakers that emits an out of phase soundwave.

 

There isn't much you can do to lower the noise honestly. Cold air intake might make the drone go away but it will make your car slightly louder. When I took out my muffler the drone was unbearable but after I put on Stille gen 3 intakes, it fixed it.
Another solution to slightly lessen the drone and sound in the interior is extending your tips out more. OEM exhaust tips are tucked in to a point where sound gets trapped in the bumper and creates more drone so look into that as well.

 

Along the lines of above, if noise emitted at the end is the issue, you could get tips that point downwards. That's a trick we used in IT-S racing to get the unmuffled rotaries quiet enough for the track DB limits.

You could also strip the interior and put sound deadener/bedliner along the floorpan and trans tunnel before putting it all back in. I'm doing that with mine, but my interior is out due to the sunroof leak issue.

 

All, here is the current plan:
-Get under the car and take measurements to see where I can fit 2 Vibrant Ultra Quiet resonators. Each resonator is 10" long, 4.5" tall, and 6 3/4" wide, so they may be able to fit in the location of the current stock resonators. They also have about 2" of material on each end of the inlets/outlets, so hopefully that'll make the cut and weld job a bit less messy.
-While the exhaust is getting chopped up, I'll spray the underbody, mainly the spare tire well, with CRC Underbody spray. After some research, this is a good product for sound deadening as well as undercoating, so if I have everything off, why not coat it all?

Depending on how this all goes, I'll consider an IPL muffler thereafter.

I think this is a decent next step after the Vibrant resonators and the underbody spray.

Is there a kit for consumer purchase? I considered this as well but couldn't find anything viable.

Extending the tips is absolutely an option! It'll look odd, but if it helps, I'm there. In terms of intakes, assuming I can figure out this sound problem, I considered Admin intakes and a tune. I think that would do enough to keep me interested from a performance perspective. Maybe I'd do an oil cooler as well and a trans cooler as well and call it a day. I took out the car the other night and had an encounter with a new Camaro SS. Would need F/I to be competitive ... not worth it for me.

I have a Sound Deadener acoustic barrier mat in the trunk right now. I cut it to fit the trunk floor, and I'm not sure if it did anything. The turndown tips are an idea as well. They would be incredibly ugly. I'd have to coat them black, or something, but I'm open to all options to eliminate the drone.
https://www.sounddeadenershowdown.co...ier-mats-60x54

 

Just get new tips and extend it literally just half an inch past your bumper. You're right the stock tips might look weird. And god no please dont curve the pipes. It'll fix your problem but you'll look like a corolla.

 

Alright all, so I did all of this last week, but I haven't gotten around to posting. I took measurements of the factory resonators and the size of the area surrounding them, but I think I've changed direction ...

Instead of replacing the resonators with bigger resonators, I found these quarter turn (?) weld-in j-pipes. I need to see how I would mount them, but I want them as close to the cats as possible to kill drone earlier in the exhaust system. These should have no added restriction, and may be a simpler solution than changing resonators, mufflers, etc. What do you think?

NoDrone - Products

 

So basically a heimholtz (sp?) resonator.

... neat!

 

Sorry - i haven't read any of the other posts - but i realized in my car i have the same problem. I noticed in order to isolate if its intake or exhaust put the rear seats down and find a big hill to slowly drive up (30 - 40 mph). If you are having the same feeling but louder - its the exhaust. That's just what the stock exhaust does.

 

Hi all, it's been a while! I just got busy with some things, and haven't had time to spend on the G37. I did finally order two of the SS 18" quarter turn resonators from Synapse. They should arrive next weekend, and I'll have them put on. I'm going to try and see if they'll fit right after the cats. There's a small space. Ideally, I would've liked to use the 24" tubes, but there's not a whole lot of room in the y-pipe area.

This is what I bought x2:
http://synapseengineering.com/synaps...resonator.html

I also think 1 or both of my front wheel bearings are bad, so I'll have to look into changing those. Youtube has some decent tutorials, so I think I'll be able to get it done myself. I'll try to use OEM parts (not that they lasted particularly well!) or TIMKEN. Just need to find a document that lists torque values for all of the bolts.

 

So where are you located? Could get another set of ears to check out your problem and compare it to a stock G37. I’m the one who wrote up the sound deadening post you linked to. I may add another addendum to it one of these days by sound deadening the transmission tunnel near the engine. I’m thinking this is a big source of noise.

Do do any of your exhaust bolts have issues or have loosened?

 

The stock system is too loud? If that is a properly working functioning exhaust system then my friend sports cars are no longer for you, time to ease into the world of Camrys and Accords. We have a BMW 545i and the stock G37 exhaust is on par with it really, its also annoyingly QUIET. What you should do actually is purchase an IPL/Nismo muffler and give it a shot. When i installed it on my car it actually got quieter than with the stock muffler which is interesting. But this is not going to end well if the STOCK exhaust is too loud for you.