Danko said:
Anybody know for sure, not just what you may have heard, why some people want the "X" pipe ???? Found functional results with and without? A nonfunctional benefit has to include the dual pipes would stay more even in height hooked together.
There was an intense article about X-pipes, H-pipes, headers with and without cats.
This was in Mustang Enthusiast-done on a Mustang Cobra.
Basically the results were 6,000 RPM's and below H and X are equal, above 6,000 RPM's the X pipe gets more RWHP. Strangely, Cats on were better than cats off, being supercharged, more back pressure to a degree. Inherently, the X pipe is quieter than the H pipe. A lot of Z06 guys went with no cats and loud exhaust, like borla with headers, only return to high perforance (not gutted) cats and stock exhaust, as they could not hear anything but the exhaust.