Put a bag of cat litter in the trunk and see if the resonance goes away

 

I still have my stock exhaust if you want to try it...it would be interesting to see how loud the stock muffler is with the RB midpipe. The inlet pipe on the stock muffler is soooooo small...it's like 1.5". It would definitely eliminate any flow gains achieved with the RB midpipe and header.

 

You ever figure this out?

I have a sjmilar setup and it's amazing! Almost no drone. Just great sound.

Its a stock 99 nb, with factory manifold, flyin miata mid pipe with cat and resonator and racing beat power pulse axle back. I love it.

 

It's a combination of the muffler and motor mounts, really.

Your setup isn't real similar, statistically speaking.

 

Concealer have you got any GoPro of inside the car exemplifying this (for what its worth) that you could share?

 

Nah, it would just be ear rape. Gopro internal mics don't like low frequency stuff much.

 

I know the GoPro mic will be ****, but I'd still like to hear it. It will be comparable to listening to other GoPro onboards and more useful than external recordings.

On a previous car with the stock BP I used the Maximworks manifold, RB cat, RB unresonated midpipe and RB muffler and it was very much quieter than I anticipated both inside and out.
On the current car w/built motor and the same exhaust setup it was quite a bit louder, so changed to the RB resonated midpipe in and the noise level was appropriate again.
Car has carpet, but none of the undercarpet fluffy crap.
I do think it can be slightly droney at highway cruise, and its a bit more droney than 6 years ago when I first bought it, but I don't think the volume level is excessive. That's why I'm curious to hear your cabin recording.

 

Can you wait until summer?

 

What! Now's the best time you can have the windows up an everything so you won't get wind noise while being oven boiled!!

 

Yeah but we just got more snow this past weekend than we did the entire last year combined, with more coming later this week. Roads are covered in salt and this car is beyond minty. I'd like to keep it that way.

 

Snow? What is this... snow you speak of.


Keep that car garaged. A kitten dies somewhere in Australia when a photo of salt induced rust on a car is posted.

 

Still working on this or am I resurrecting a dead thread?

Either way: in my NB1, I had a RB header -> resonated catless mid-pipe -> RB muffler and the thing was murder with a no-headliner hardtop. I hated to drive it.

Two things improved it:
1) putting in a resonated AND catted high flow mid-pipe. The extra restriction of the cat helped a bit with the drone.
2) adding fabric in the cabin. I noticed that the drone was significantly reduced when I was using the soft top vs. the no-headliner hardtop. So next winter, I tested this with a literal towel taped to the ceiling and it worked like a ghetto acoustic panel. Less sound bouncing around in a fiberglass cabin = less drone.

So - I'd look to tune your exhaust a bit more with a resonator, and add a headliner if you don't have one - or make it thicker if you already have one.

 

Dynamat or some form of sound deadening works wonders here too. When I had the interior stripped in my MSM, i bought a roll of Dynamat to lay down on the bare floors and made a drastic difference in drone and interior noise. Added a tiny bit of weight, but since It's a street car that may see track time once in a while (and i have no plans to be competitive with this car), it was well-worth it.

 

This is the original hardtop, it has that foam layer thing on it. Was considering getting some sort of more headliner-looking thing for it anyways, so i'll look into that.

As for the midpipe, i'm torn between my OCD wanting matching things, and a midpipe being an easy thing to replace.