The other day my buddy was behind me and he said that I get black exhaust when accelerating hard and when shifting. My car burns almost no oil. Im running a catco cat. I am also running a mugen chipped p28. I have noticed sut on my rear bumper. Im thinking that the mugen program, which runs rich, combined w/ the high flow cat causes the black emissions. Does this seem right or is this a sign of a greater problem.

 

Most likely it's the computer. Most of my friends are using the chipped P28, and they throw a little smoke when they open it up.