by PhreakdOut » Tue Aug 26, 2008 7:44 am
X-pipes are great for sound reduction. They can also act as a balance tube but personally I feel the disruption in flow outweighs the balancing effect.
Tenneco had developed the X pipe on the Z06 vette and the Gen2 Viper project. Both projects had to meet pass-by requirements on huge engines but the underbody had little to no room for large mufflers.
The X pipe couldn't work out for the Viper but we made something similar to a balance tube where the driver's side exhaust crosses over to exit on the passenger side.
The Z06 program worked out well. I believe we were running dual 3" pipes (A nightmare of it's own). The X-pipe helped knock off a few dB but most of the help came from a vacuum actuated valve attached to the inboard tailpipes. At WOT, the valves opened up so exhaust flowed from all 4 tailpipes.
Soon after the Z06 hit the streets, all the aftermarket companies copied it. It's on the Z06 so it must add power. Heck, even Tenneco added it to their Dynomax line and sold a ton of them.
They are easy to make. The X is formed by a clamshell top and bottom half that is welded to gether. Expandable end tubes are welded to the 4 ends. Very simple, not too expensive and they can charge a good price.
(More info than you wanted. Sorry to get all Cliff Claven on ya.)
-- The Phreak
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