so i'm running bio diesel and i put so regular diesel in my rear tank and ran on it for a while in hope of getting some black smoke. well i got none!!! now when i switched back to bio diesel i get a bit but its just a short shot of it . how do i make it smoke ???? WHAT DO I HAVE TO DO??? its got a stock intake 4 position chip and 4 inch straight pipe? is this good or bad? i heard the reason diesels black smoke is because the lack of oxygen to fuel mixture??? is this true?