JBrady
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Here is an article that may be helpful to understanding what gains and losses are found in an exhaust.
Test engine is a large 455cid/7.5 liter OHV Pontiac V8.
Mufflers were tested as a SINGLE to magnify the differences.
Between open headers and a single muffler the maximum difference in 1/4 mile testing was only 2.4 tenths from a 12.97 to a 13.22 and 2.6 mph from 102.6 mph to 105.1 mph.
Remember, this is with a SINGLE 2.5" muffler on a 7.5 liter engine.
Interesting nearly the best muffler tested was a turbo style which has 3 internal tubes.
This muffler as a SINGLE 2.5" I/O muffler lost only 6 mph and 0.8 tenths in the 1/4 mile (about 6-8hp lost over open headers).
http://www.pontiacstreetperformance.com/psp/exhaust.html
Test engine is a large 455cid/7.5 liter OHV Pontiac V8.
Mufflers were tested as a SINGLE to magnify the differences.
Between open headers and a single muffler the maximum difference in 1/4 mile testing was only 2.4 tenths from a 12.97 to a 13.22 and 2.6 mph from 102.6 mph to 105.1 mph.
Remember, this is with a SINGLE 2.5" muffler on a 7.5 liter engine.
Interesting nearly the best muffler tested was a turbo style which has 3 internal tubes.
This muffler as a SINGLE 2.5" I/O muffler lost only 6 mph and 0.8 tenths in the 1/4 mile (about 6-8hp lost over open headers).
http://www.pontiacstreetperformance.com/psp/exhaust.html