Power Vault I Muffler Insides

I decided my Power Vault I was getting too loud after 75000 mi. As a historical note, when I got it off, I cut opened the body to have a look at the construction. Seems to be just a heavy duty glass pack.
I found an inner straight through perforated tube shaped like an expansion chamber. The fiberglass was missing in one large area. The stainless steel was still in good shape. I could repack the fiberglas and weld it back together almost good as new.
At the recommendation of my muffler man, I tried a Magnaflow 4x9, 20" body, which is a straight through design in stainless steel, it is a little more quiet below 2000 rpm, but hits a loud resonance at 3200 rpm. Not good.
I did replace the tail pipe with a stainless 2 1/2" all the way to the stock tip, also 2 1/2".
Next I will try the Dynomax Super Turbo 4x9. Not in stainless, but still lifetime warrantee. The three pass design will have a bit more back pressure but I don't expect it to be noticeable.
Two photos in gallery.
Roy

http://www.vehicross.info/gallery/data/500/Muffler2.jpg
http://www.vehicross.info/gallery/data/500/muffler1.jpg

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Originally Posted by newthings

At the recommendation of my muffler man, I tried a Magnaflow 4x9, 20" body, which is a straight through design in stainless steel, it is a little more quiet below 2000 rpm, but hits a loud resonance at 3200 rpm. Not good.

Next I will try the Dynomax Super Turbo 4x9. Not in stainless, but still lifetime warrantee.

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The more and more I hear about the Magnaflow muffler being too loud at higher freeway RPMs, the more I don't like it. By far, the very best muffler for the VX is the DYNOMAX - SUPER TURBO in the large 20" body. When it comes time for muffler replacement in my VX, the Dynomax- Super Turbo in 20" body will be my only choice. Just do a forum "search" for the thread entitled: "Muffler Help Needed"