I'm trying to pick a muffler ... for a while I was onto dynomax, but then when I found out what a fiberglass-stuffed muffler does over time (gets louder and the stuffing 'blows out') i decided I don't want a stuffed muffler.

I want something near OEM quiet at idle, and "restrained" at WOT. I don't want to attract a lot of attention.

I currently have a flowmaster 80 series crossflow...idle sound is fine, WOT is a bit loud, and i understand that they flow very poorly.

I could care less about having the "dual exhaust" look, so one (or two) on the left is fine. I actually like the SLP "dual dual" descriptions I've read (quiet and good flow) but they seem rather pricy new, and used availability is spotty.

So, I found these over at flowmaster ... the 70 series, "Big Block II" for high performance street, truck, and SUV.

http://www.flowmastermufflers.com/pd...iesB.pdf?37,10

The 530712 seems to fit the bill. about the right size, 3" inlet on one side, two 2.5" outlets on the other, ...

Any thoughts on this 70 series? flow abilities/restriction thereof? Anyone used one? It's not a crossflow muffler, so it should be decent, I'd think. ANd since they are sold for big block trucks and other large SUV types, they should have reasonable airflow for my 5.7 ....

 

I didn't click the link, but from what you described, sounds to me you are looking for the Hooker Aerochamber muffler. Do a search on "Hooker" and you will find plenty of info and descriptions on what the sound will be like.

 

The 70 series Flowmaster is said to be fairly restrictive, as are almost all Flowmaster mufflers. If you want quiet, I'd recommend a Borla XS muffler. They're a more value-concious Borla muffler, but they are said to perform nicely and be quite quiet and refined. They even offer a dual-outlet version so that you could make a setup that looks like the SLP 2-on-the-left exhaust. A friend of mine also has a normal Borla turbo muffler, 3" in/ dual 2.25" outlet. Sounds very good yet fairly tame, even with a heads/cam package.

 

too loud at WOT or heavy acceleration, otherwise i'd consider it.

 

any idea what they use for sound reduction? it says straight through, so I assume that means, no chambers/baffeling .. but if it isn't a stuffed muffler either... is it just a perforated tube in a hollow shell? hmmm.

a picture or cutaway would be great about now.

 

They are stuffed, but the stuffing used in UltraFlo's and Borlas is made from either stainless steel or some sort of ceramic I believe. It's not supposed to blow out. My dad has an 82 Vette with dual Ultraflos on it and they have not gotten even slightly louder in the 6 months or so they've been on the car. All the cars that I've heard with a normal universal Borla muffler such as the turbo mufflers or the XS series have been very consistantly quiet. Deep, but quiet. Ultraflos however will wake up somewhat at WOT, but Borlas not as much.

If you want quiet you're gonna pretty much need to have a "stuffed" muffler. The chambered mufflers are pretty much unconditionally loud, and if they're not they're very restrictive.

Also, the SLP "Dual/Dual" catback seems to be a favorite for low noise, high power. They're not very cheap tho.

 

Just a note on 70 Series I have...I'm fairly happy with it. Oh I remember when I was installing it...at first was kinda scared or something LOL but turned out very easy to install.

Anyway, I got it HERE (in case, anybody wants to try it)