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Originally Posted by BigBOSS
The stock exhaust already comes with an H-Pipe. Not sure what the difference would be between an X and an H pipe though.
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Short version of the difference between the two is that H-pipes equalize pressure differences between the left and right side of the exhaust systems with very little mixing of exhaust flow between the sides. X-pipes equalize pressure differences as well but they also mix the exhaust flow from both sides.
Both are good for performance and noise control but H-pipes tend to help with performance more than X-pipes.
Excerpt from a really good article on exhaust systems:
http://www.superchevy.com/technical/...exh/index.html
Quote:
Virtually all V-8 exhaust systems can be refined by the addition of a balance or X-pipe. These have two potential attributes: increased power and reduced noise. Extensive dyno testing on both of these factors has indicated balance and X-pipes are 100 percent successful at reducing noise. The reductions amount to a minimum of 1 dB to a maximum of 3 dB with 2 dB being common. As far as power is concerned, things are a little less certain. With engines between about 325 to 550 hp, experience indicates that in about 60 percent of the cases (mostly with balance pipes), the engine can deliver as much as 12 additional hp, with 5-8 being the most common. The other remaining 40 percent tested showed virtually no change in output either up or down. Based on such results, we can conclude that a balance or X-pipe is always a positive asset and never a negative.
Balance pipe sizing seems not to be overly critical. The only really influential dimension is the pipe diameter. This needs to have an area at least equal to that of a 2.25-inch diameter pipe (4 square inches) with 2.5 to 2.75 inches being preferable. Though limited to tests on engines up to a little fewer than 600 hp, there seems to be no measurable benefits to using a crossover pipe bigger than 2.75 inches in diameter. As for the crossover length, dyno results indicate that 18 inches responds in virtually the same manner as 72 inches long.
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