I have replaced a cat with a resonator before, and it made the car quieter.

 

You got my attention. Was this on a Miata?
Which resonator?

 

Lets agree that adding more things to the exhaust that are not straight pipe will make it quieter, mmkay?

If I added a cat to my exhaust (move resonator back, add cat where resonator now lives) it would get quieter. If I added another resonator downstream of the current resonator, it would get quieter. If I added a flapper thing to my exhaust, it would get quieter. If I added a resonated exhaust tip to my exhaust it (might) get quieter. Anything that isn't a straight pipe is going to make it quieter.

The practical concern is how you are going to fit and support all this **** under the car

 

well we know there's room for a cat AND a resonator under there cause the msm has both. AND a huge muffler like the Maggie if you place it right. so really, it's about how good of a fabricator you are and how not terrible you are at measuring and fitting

 

OP is getting an MKTurbo setup. Right now we are just trying to figure out how much to spend on adding resonators and what type. He is the first person to want to go even quieter then just the giant magnaflow muffler.

 

Well, Shuiend has said, tentatively, he thinks he can fit 18" X 5" resonator like EO2K, and a second 12" X 4" resonator, plus the magnaflow, so maybe I should stop overthinking it and just go with that.

EO2K, was there a reason you went with the regular bottle vibrant over the "ultra quiet" one?

 

Long time ago. 1.6 miata. Greddy trubo. Installed cat back. Too loud. Then replaced cat with straight through resonator. Quieter.

 

And if you still want it quieter like me, add a flapper valve (either spring or cable or boost actuated)
The downside of the spring flapper I did is it will let out a rattle or 2 when taking off from a light.

 

I used to have a video where I let the car idle and then I manually opened the flapper and let it close ... open... close. There was a substantial effect on the bass note.

 

Ok, thanks! I think I will start with the 2 resonators, and if it's too loud, I'll add a flapper later.

 

I can say, I am way to lazy to make a flapper valve. So you will be on your own for that if you want to go that route once you have the exhaust.

 

Also, just for reference, I called Magnaflow and spoke to their sales engineer, and he said that the resonators do not utilize offset pressure waves to cancel sound, but rather just absorb vibrations using the packing. I think only chambered mufflers and Hemholtz resonators use destructive interference to reduce sound.

 

From 2005:
https://forum.miata.net/vb/showpost.php?p=1429799&postcount=15
I think I had it installed it in 2002. This was my first attempt. I had it redone with an even bigger Magnaflow, which I then kept for many years until upgrading to bigger trubo and 3" exhaust... which needed the flapper to cut the bass.









No I was the first. I was also one of the first ones to use the giant-*** Magnaflow, before it became common. Back when I had a 2.5". It was quiet enough, with a resonator and high flow cat. When I went 3", it was too bassy, so I added the flapper.

 

Yeah, I wouldn't expect you mess with that. I'll figure it out :-)

 

I have the giant magnaflow on one of my naturally aspirated miata's. It is 2.5" pipe with 2 2.5" resonators. Thing is quieter then stock and most people don't believe me when I tell them the exhaust is that large on a naturally aspirated car. I was very surprised how nice it sounded.

 

Unless this appears to be true about the "Ultra Quiet" Series from this thread https://www.miataturbo.net/diy-turbo...-76891/page2/:

 

I was looking at building a 1/4 wave tube for my 113Hz drone, but I don't know where I'd fit a 30" pipe.

 

you guys forgot my super science test:

 

Anybody ever heard of these? They have little louvers to capture more frequencies. Stupid expensive though.

https://solo-performance.com/qr-resonator-series

 

why toss away 7%, when all you need is the bigmaflow anyway?

it's just a louvered muffler...you can buy the same on ebay for $15.



for $130, vs:



for $35.99