dyno #'s on all the cat backs vs stock

[Tucson_02Silverado]

The concenses on this forum and others seems to be loud when selecting cat backs or muffler replacements. But I do see that there is an interest in a mellow factory F-Body type rumble with no resonance in the cab at highway speeds. Beyond the sound though, with theses replacements with labor costing $300+, is there any real performance gains? Yeah I'm getting old and likas my quiet, but factory exhaust used to be very restrictive yet I look under my 02 and the factory cats are now adays fairly efficient and barely restrictive in flow. Then the pipes are smooth runs to the muffler (not 100% manderal type bends, but not that bad). Even the exhaust manifolds are looking a bit like "mini" shorty headers.

 

So are there any complied dyno #'s first using the in/out factory pipes and just changing mufflers vs factory? Then how about #'s of factory vs. cat backs dual and single out along with dual body side out (one out pipe becomes a lot longer, effect?)

[Black02Silverado]

Well I don't have any numbers but I can say this much. When I called Flowmaster up to get the number of a muffler. I talked to the tech guy and he said that the performance difference on their cat back system and my just changing out the muffler is the same. He told me to just get a muffler and save the extra cash for my truck payment. So I went with the big block 70 series muffler. It mounted right in place of the factory muffler and has a little note to it but nothing loud. Inside the cab you can hear some but at idle and cruise it is hardly noticeable. I figure it opened up the system a good bit more than stock and helped the engine to breath but with no loud tones.

 

When I want loud I just drive my 65 Impala SS with dual 50 series flowmasters, headers and no cats.

[bigtruck21]

go to some of the webpages for dyno info. I posted something a while back about hp and torque in magazines, but didn't get many replies. I was hoping people with different mags would look up some numbers. I posted some numbers from sporttruck. I'd assume the mags would be more accurate than biased companies in rating their own products.