I know this thread will cause some controversy, but I've been giving this theory some thought for a while.

If a Y-pipe was placed in the right location and with the proper merge angles, correct length of inlet piping from headers and proper increase in size at the Y, I feel it could achieve very close flow numbers to an X-pipe.

Can someone help support of negate this theory?

 

A y-pipe can probably flow as much as a x-pipe, but the x-pipe will help pull (scavenge) exhaust out of the headers.

Shawn

 

You can make an H-pipe flow as well as an X-pipe as well, but Spanky nailed it on the head as to why X-pipes are great

 

X-pipes scavenge, end of story. An X-pipe and some stepped headers and the exaust should pull it's self out of the chambers.