[JFM-jr]

Originally Posted by jwdominick

although it appears to go through the same baffling, it actually doesnt. there was a cut away done a while back to help explain but its essentially a straight through pipe when its open

Yes on the factory NPP if the valves open exhaust flows thru the outside tips bypassing the muffler internal baffles. I was asking the OP what the valves bypassed in this setup he has made. It appears it simply adds an additional port to let exhaust escape the exhaust flows thru the same internal muffler baffles regardless of valve postion.