| A straight through design has less back pressure so the gasses flow faster through the exhaust rather than being constricted through bends and the muffler...
Kinda like if you're blowing into a straw, it'll be harder to blow if the straw has bends in it and an ear cleaner in the end of it... Same with a muffler, it restricts air flow...
And power gain on a 318is wouldn't be much at all with sports exhaust system, somewhat around 5-8hp at the crank, the 4 cylinders lack heaps of power...
I wouldn't bother getting twin pipes for a 1.8L engine as it's pointless and would only be cosmetic...
__________________ Project 2: BMW 325i  |