picture this.....your are moving along down a tunel in water cramped in a 3' tunnel with 4 other "boats" side by side. you are moving along nicely then suddenly you make a right turn and the tunnel becomes 1.5'. now, how in bloody hell do you keep the same pace going through that tunnel? YOU DON'T. a couple of the "boats" would be pushed back and forced to go through the turn after the others, even though you were side by side before the turn! kindof a retarted scenerio, but you get my drift! the same with exhaust, you wanna disrupt the flow as little as possible!