I just finished replacing my stock dual cat Y, and 1LE cat-back w/a flowmaster....w/a new 2.5" mandrel bent Y, 3" cat back to a 940 CFM Dynomax muffler (P/N 17227), and 2.5" mandrel bent tailpipes.

Before at ~2200 RPM, w/ the Flowmaster, it got REALLY loud, then quited down above that. Now at that same RPM, it get's little louder, but makes this -what I call- "packy" sound. I hate it. It sounds cheesy. Any one know what causes this, and/or how to get rid of it?

-Tom

 

Is this "packy" sound under load or when you let off?

 

Good question.

It does it under both decel and accel. But the "packiness" and noise in general is MUCH worse under accel, right at that particular RPM. Under that RPM, it is mellow deep and bubbly...the way I like. AT that particular RPM, it gets MUCH louder, starts "packing" away like crazy, then quites down above that RPM, but continues w/the sharp, crackling "pak" every cam revolution. -This is all under accel.

Under decel, it's much less annoying, but it does it all the way back down.

 

Since its hard to describe sounds I'm going to venture a guess that it may oossibly be the Flowmaster sound? Have you heard any other flowmasters on a third gen?

 

the sound i think your talking about is the glasspack sound...like you can actually here the fiberglass packing like fluttering away inside the muffler...usually that is common with fiberglass packed mufflers like ultraflo's and things of that nature, i'm not sure if yours is a packed style muffler...but that could certainly be an answer...

 

I think I know the sound you are speaking of. I get it too on my Hooker Areochamber when the engine is under load. It too happens around the 2500-3000 range. It really bothers me because it sounds like a ******* glasspack sometimes. I put turn-downs tips on mine and that helped alot believe it or not.

 

YES!! Like an old school '70's Glass pack. It makes a *SNAP* w/every cam revolution -or exhaust pulse.

So turn-downs, huh? That's actually a great idea, (so thanks) but I'm bummed because it's not what I was after -aesthetically.

 

I know what your saying.....I used to be into the big chrome looking tips when I was younger...now I like my turn-downs tucked up under the bumper...simple and doesn't say "look at me, I make alot of noise so I must be fast". I must be getting old

Anyways...I put the turn-downs on and it cut the noise level ALOT...must be because it deflects it onto the road surface instead of straight back at everyone else. It stills "packs", but not nearly as bad.

 

Maybe I'll give it a try...slap on two 90* bends and see how that sounds. The sound NOT being annoying is more improtant to me that then looks.

I WAS going for a nice, clean, straight pipe on each side, w/a 45* cut at the end, made of Stainless. Much like a Mustang 5.0's tail pipes. I think it looks clean, classy and mature (for a Camaro). But I just may have to forgo that look. No "big" and no "chrome" for me thanks! Not my 'bag'.