Join Date: Jan 2019
Location: Sedgwick, Kansas
Shorty glasspacks like yours, but bolted directly to the headers without pipes would be a 9. Maybe a 10, as they can be just as loud as open headers in the right conditions. If those are toward the back of your car, they probably do help a little, so call 'em a 7.
While very low-restriction (even more so than a straight pipe!), glasspacks are a perforated pipe wrapped in fiberglass, inside a shell. The matting gets full of soot and stops being fluffy over time (or blows out the tailpipe), at which point they tend to be pretty dang loud. Think Thrush and Cherry bombs. Usually, the longer they are, the quieter they are, but no glasspack is going to be mellow and tame sounding. They have a beautiful savage snarl, which changes to explosive cackling as you let off on the gas. Absolutely classic exhaust sound for a musclecar - but often really annoying out on the highway. The quietest glasspacks are probably going to be about a 6-7.
"Turbo mufflers" have a wider body and typically force exhaust to travel in sort of an 'S' pattern inside. They offer a lot more sound deadening, but they're also a bit more restrictive. Magnaflow is an exception to this. They are called "turbo mufflers" but they are more like 'better built' fat glasspack mufflers. They are superior in flow to most Turbo mufflers, but have better sound-deadening than a glasspack muffler. While not 'quiet', these are probably more like a 5-6 on your loudness scale, when combined with a full exhaust.
Lastly, chambered mufflers are pretty common these days. Think "Flowmasters". They come in different lengths, which quiet things down based on size more or less. Bigger = quieter. Your typical Flowmaster 44 sounds like someone lighting off packs of Black Cat firecrackers in a culvert. It is a hollow, boomy, annoying sound. Instead of depending on damping materials and perforated pipes inside, chambered muffles use baffles to help attenuate exhaust pulses. They would rate probably about a 6-8 on the loud scale. Their hoarse, sad, echoing thud attracts droves of millennials and fraternity kids with lots of money but no taste or common sense. (What? No! I'm not biased!)
The classic stock muffler setups are typically a combination of perforated pipes and fiberglass damping inside. Most of them are pretty restrictive.
Edit: OOPS. I was putting a "1" at more like "early 70s luxury car quiet". I'd say a full stock mustang with the resonators and cross flow exhaust would be maybe a 4 on that scale, so adjust my numbers accordingly!
"No matter what you are, be the best one you can." -Abraham Lincoln
Last edited by Grimbrand; 07-24-2019 at 06:34 PM.