I'm fighting low RPM/speed drone with some Dynomax super turbo mufflers. Drone is at 1300-1700 rpm/ 15-35 mph. Someone thought I should get some glasspacks. I've never used glasspacks. I want a fairly quiet exhaust system. But fairly quiet I mean : New Camaro / challenger sound or quieter. About 25yrs ago I worked as a mechanic. Used to install some type of NAPA glasspacks, that were real quiet. Don't remember much about them though. So are there glasspacks out there that are fairly quiet when doing normal around town driving & highway cruising ? I'm sure the will sound louder when you want them to ( not that often for me/ I just cruise)
the mufflers from napa I think you are talking about are walker continintals they were pretty quiet at low speeds and idle I wonder if they are still available
porters are good choice if you run them out to the rear bumper. smithys are a bit rasper but ok even the old thrush glasspacks sound very mellow out the rear. any of these make sure you get a long body 25 inches or longer that helps the overall sound.
Might add a crossover pipe and move the muffler location, maybe a different turbo muffler. Drone can be eliminated by moving its location in the pipe length, your mufflers are probably right under your seat. You can get new camaro mufflers for cheap from someone swapping them out if you want to try them. Glasspacks just do not sound good to me.
You probably want to go with a 'louvered' glasspack as opposed to a perferated one. The longer the mellower usually. I had the same 'droning' problem with a set of Flowmasters. I went with cherry bombs because they are perferated and I wanted that 'rap'... ran out of the back through bellflowers. It is actually surprisingly quiet at cruise speeds.. in the cab anyways. And when you stomp on it, it has the nice rapping sound.
Google "Helmholtz resonator exhaust" I have yet to add them to my truck but I plan to in the next few weeks - from what I read they perform miracles.
So are the louvered glasspacks a quieter type ? Do you install them so the exhaust flows OVER the louvers/ or so the exhausts gets caught in the louvers for a quieter operation? I'm not into to loud rapping sound thing...just a nice mellow cruiser.