It's ******* annoying. I had a 38mm turbosmart on my Forester XT and it was the most annoying, obnoxious sound, especially on the dyno. When I was riding with the windows closed it was OK, but I had the whole interior Raammatted and close-cell foamed to make it quiet. I was still annoying everyone else though.

Just plumb it back into the exhaust downstream.

A bigger WG is actually quieter. Like a 44 Tial vs the 38.

Frank

 

It's loud when it opens, very loud. Is it unbearable, not at all. If you have a 2" exhaust and run a cat and a large muffler, then it will be much louder than what you are currently hearing at WOT. If you already have a full 3" catless setup, then it's just a little bit louder than what you are already hearing.

If you have a setup that spools instantly and you are only running 10# of boost then you will hear it often and it will annoy you if you use the car as a daily driver. On the other hand, if you run a slightly larger turbo and a higher amount of boost, then it will never open under daily driving conditions. During spirited driving you will definitely hear it and so will everyone around you.

One last thing to do is actually hear a Miata that runs this setup in person. I watched so many videos of cars and they sound nothing like my car does. Even the videos I have made of my own car sound nothing like how it sounds when you are next to it or riding in it.

 

All I've heard with an atmosdump is Matt Andrew's car and it has about 3" of side dump exhaust so it doesn't really compare.

 

How loud it is depends on how much boost you are running. i.e., if the turbo requires a majority of the exhaust flow to maintain requested boost level, the dump will be quieter. And vice-versa.

If you run big boost on a big turbo w/ a small engine, that's a recipe for a quiet external dump.

examples:
The external on my daily dsm (2.0L / 65Lb/min turbo) got a lot quieter moving from 18 to 24psi. Not bad, ran 2 years.

Running an external dump (same 2.0L) with a very small stock T25 at 12psi results in an extremely loud and disgusting sound. Absolutely horrible, lasted 1 day.

 

I had one on 3 different DSMs and the first time I rode in an EVO with the external plumbed back in, I was in heaven. The external dump is so loud and obnoxious after a while. It's fun at first opening it up next to people to see their reaction, but it really gets old quick. Add into the mix that the miata is a convertible and it'll be even louder.

I definitely recommend plumbing it back in.

 

I just like to say my friends MR2 turbo dumps to atmosphere and the questions is not how loud its how awesome is it?
Its just brilliant I cant wait to do it

 

It's just brilliant how you had to drag up a 5-week old post to tell us about your bro's MR2, broseph, I can't wait to REACH THROUGH THIS SCREEN AND HIT YOU IN THE FACE WITH YOUR KEYBOARD

 

It's ok to read old threads, but to resurrect an old thread to add completely worthless commentary is juvenile.

 

lol, Savington said you were a bitch. I recommend you never put you location because I'm a pretty bad-*** dude and you don't want to **** me off. I'll wear your face as a ******* mask...I've been to prison, and I learned quickly that when you want to teach someone respect, pliers and a blow-torch get your point across rather quickly.

 

Thats right! Hustlers on the Right

 

talk **** again and I'll chop you in half with a sword.

 

there's a striking resemblance, mostly in the the fact that he's white, wearing a ball gag, and covered in bloody urine.