finally added my catless cobb downpipe and i love it although i noticed it backfired when downshifting and was wondering if that can be bad its not that loud and its only happened twice over the passed week
its one of my favorite things about the catless, I was behind a black sti on 285 at roswell rd. last week and when he downshifted he backfired and shot out a flame, it was sweet.
Also if you have a Dual Port BOV that is turn up to VTA more then recert it will backfire. If you turn down more to recert it wont backfire as often.
Ever since I did the 2.5 swap and tuned, mine backfires alot! I haven't seen it yet but it sounds sweet, I will be just cruising and let off of the gas and then BOOM! alot louder than it used to be on the 2.0. I have noticed a couple of cars put some distance between me and them after it happens.
Between the after-firing and the unequal length headers, a lot of people asked me if my car needs a tune up. I tell them my car is tuned better than theirs! ...At least for power...