Let me apologize in advance. This is barely advanced tech, and only qualifies because it deals with the consequences of different choices on exhaust flow. If there was an exhaust forum, I'd ask it there. Also, if any moderator wants to move this somewhere else anyway, I won't complain.


I'm done experimenting with different ideas, and I'm ready to put together the final system.

I have headers coming back into "muffler delete" pipes, and the rest of the exhaust will be from there back.

I decided to stick with 2.5" to keep the exhaust velocity up and drone down.
I have a set of cutouts in that size, but let me leave that out for a moment.


Without the cutouts, the exhaust would come back into an "X" pipe of the 'siamese' type, as opposed to the 'hard X' type.
Sort of this: )( as opposed to this: X


From there it will come back, into 2.5" x 18" glasspacks before going into a tailpipe, over the axle and into a large resonator before the tip.



Now, here's my concern:

I don't see how installing a cutout could possibly avoid being disruptive to the exhaust flow when the caps are on. I have three choices:

1. Put the cutouts at the front of the exhaust system; before the "X" pipe.
2. Put the cutouts in the middle of the exhaust; just before the Glasspacks.
3. Not use cutouts.

Obviously, the system, lacking traditional mufflers, would be pretty free-flowing, with good velocity. Do I even need cutouts? If I use them, should I locate them further back, so that any impact on the flow would be as far away from the engine as possible?

If I haven't made it clear, I am very concerned about the flow, both in terms of volume and velocity. I would rather do without the cutouts if it would have a serious impact on that.

 

Never mind. I decided to not use cutouts.

Having said that, I would be interested in hearing from anyone who has input on how the "Y" design of cut-outs affects exhaust flow and velocity.

 

The exhaust gas is going to travel the path of least resistance (pressure wise). May be a dip in velocity at that "Y" point, due to the change in section area, but it should recover quickly. Some effect yes... but I don't think it'll show up on a dyno.

-Mindgame