Good read and a vid showing the results and the history of creating a good exhaust.
and the Vid.
and the Vid.
David Vizard's PowerTec Zero loss sound legal muffler systems
- Thread starter Jim Rockford
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David Vizard's "How To Build Horsepower" paperback book Chapter 14 (Mufflers to Tail Pipes has the same pictures and charts he shoes in the video. I bought the book a few years back! The book is quite good.
Doug
Doug
Very cool video as far as the info. I used DV's tech & testing data when I picked the mufflers for my dually's BBC. It's very tame as far as noise level especially considering it has full length 1 7/8" headers through 3" head-pipes/mufflers into 2.5" tail pipes.
I wish he'd put up dB numbers for straight pipe, zero loss, and a blowmaster or something equivalent.
I printed off some chart stuff from some of his testing I found when I did the BB set-up for the dually. The ones I used were No.3 on the 'flow' list (open pipe No.1; Borla race bullet @ No.2) & No.2 dB level (OE muffler @ No.1). I'll see if I still have the tech stuff in the folder.
His testing muffler flow was on a flow bench, Db is going to vary depending on alot of different factors. you can almost bet that shitty *ss flowcrappers are going to be the loudest because everyone knows if your junk is loud its gotta be fast right..LOL
I thought it was the racing stripes that made it fast. I saw the commercial.
The system I have for my Malibu was from Torque Technologies Exhaust. I got it beacuse of a test Pontiac Street Performance did a long time ago. They ran different systems on a 455 wagon. Tested for 1/4 mile, noise, backpressure, CFM. What they ended up with was basically a zero loss system compared to tuned open headers. Mine is 3.5" off the collectors into an X pipe, then 3" after that through Dynomax turbos and GN style tailpipes. IDK how loud it will be , but the owner told me it will be surpisingly quiet for 3".
I found a link to the orginial article:
Tommy
I found a link to the orginial article:
Tommy
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I based the exhaust on my big-block dually using that testing.
My tail-pipes dump @ a 45° angle near the outside corners under the bed @ the back bumper. It has enough BBC rumble to trigger alarms when they're sensitive & in close proximity but almost stocki-sh quiet @ light to medium throttle. I'm sure the 20' of pipe it has to push through helps as well.
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