Backfire after tune?

AstatenateZ

So a friend of mine has a 09 370z AT and he pops flames like crazy when his car is warmed up and he is in sport mode (slap shift) and he shifts at like 7,500rpm he pops flames. Like big flames. Not just little spits of flames. And I was wondering how he does that when everyone on here says NA automatic can't do it. He said he didn't plan for it to happen when it does it just does. He has UpRev tune, non catted / non res test pipes, full cat backs, and stillen G3 intake. I have basically the same mods as him but I have pulleys from NST. And no tune for another month or so. I've heard my car pop before but never seen a flame. Is that something a tune can do? Where it runs a little rich? I also drive a 7AT. Mine is 2011. Only difference in our cars is I have light weight pulleys and no tune. I wanted to have a 2step map for when the car was parked to do, but was told by UpRev themselves it was not possible. If that's the case. Then how come I can get on Instagram right now and see multiple videos of just that. 7AT having their fuel cuts and restore altered to where they're popping flames. Not an actual 2 step launch control but it cuts/restores fuel to where it dumps fuel into the exhaust and 2step flames come out.