This is what I was talking about, the rears join the oppositte side. This is the HMF system which is identical to my UFO system.
On my buddies Marks exhaust it is very similiar BUT the rear down pipes curve around and join the front pipe from the same side as the rear down pipe.
Clearly a different scavenging philosophy and I have no clue which is best.
I don't think the crossover comes into play when naming a configuration 4-1-2, 4-2-1, 4-2 etc
I would consider HMF, the old style UFO, and Marks to all be technically called 4-2 systems; the Marks being a 4-2 with a crossover. Getting technical about it they would really be two separate 2-1 systems.
It's like thinking of a V8 with headers and duals as a 8-2 or if you wanted to get really technical it would be two separate 4-1 systems.
This new UFO pipe from looking at it would be a 4-2-1 instead of a 4-1 as he is calling it. I say that because of the order of pipes joining from 4 down to 2 then down to 1 right before the muffler can.
I've seen what I would call a 4-1 on a Vmax, it was an obsolete Two Brothers system and ALL 4 pipes joined the collector at one time making it a 4-1. It also had a big freakin' dent in it cause of very little ground clearance.
