I installed headers and had high flow cats welded in. Cat back is straight through, no mufflers or resonators, to the pictured exhaust piece, which I don't think is a resonator or muffler. Now, the exhaust is too loud, to much brrrraaappppp and highway drone. What is my best option for replacing the shown piece with a resonator or muffler to tone it down a bit?




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On that 1985 Supercharged stroker I'd go with just the resonators since you only want to tone it down a "bit".

 

With what youve done..drone will be your life.

You want a resonator in your exhaust.

Do what I did here: https://flic.kr/s/aHsjx2c3mg

Find your peak drone frequency, work out the 1/4 wave of that frequency at say, 500 degree air temp, and install in your exhaust(s) tube(s) a chamber of that length, as large of a pipe ID as you can get to match what is there already..if it has to be smaller to fit, fine, but larger is better.

Youre going to be +/- a fraction of 25" of closed end tube...depending what RPM and frequency you discover you want to -mostly- get rid of.

 

Looks like an old fashioned glass pack....a perforated central core with fiberglass matt around it. Shie a light in it an see if you can see thru the unit. It probably has no baffles at all. So it is more resonator than muffler.

 

As best I can describe it, the entire point of the resonator is to target the higher pitched frequencies that are annoying/damaging and in doing so permit the use of a tamer muffler with less flow resistance that kills power.

If your picture shows all that you have to tame the sound I am surprised you are still at liberty! You must be popular with the neighbours unless they are a few miles away.

My system consists of a Louie X pipe, a largish bullet muffler where the original resonator used to be and then the RMB, the motor is not quiet but it is not obnoxiously loud either and I have the option to mount the stock rear muffler any time I want and/or the front box. I also have the original resonator sections so I can revert to the stock exhaust any time I want and/or need to.

 

Before replacing the headers, it had the stock cats and then the current cat back and it wasn't too loud. Obviously the combination of headers and the new high flow cats kicked it up to 11! Hopefully, replacing that last exhaust piece with a muffler will tame it down to something acceptable.

 

Here's a video of the current setup. I'll have a rear muffler fitted on Thursday and will post that video, too.

 

Sound great to me Brett

 

sounds great for the race track,
but not so much for your neighborhood or going on long drives 3 states away
a quieter exhaust adds to the comfort of the machine and reduces noise fatigue

 

I found the Dynomax Super Turbo mufflers are great at reducing some of the resonance we complain about with straight exhausts. My car is set up so the muffler is modular (single 3" pipe after the cats), in that I can swap it out from my straight-through fiberglass insulated muffler, to that turbo muffler any time I want to quiet it down a little.

Given that there's almost 10 feet of exhaust pipe after the headers, a muffler such as a turbo muffler is not so restrictive as the exhaust gas is at its coolest at the end of the pipe. Keep the heat up with chambers in the muffler and proper exhaust piping diameter, and you really have no worry about HP or torque loss.

 

I replaced the rear, glass-pack muffler with a spiral muffler and the sound is much better. The rasp is a little higher pitched, but doesn't brrraaaapppp under hard acceleration or drone on at highway speeds.

 

Is that a Moroso spiral?

 

or spintech?