I know the reasons why old cars backfire, but I've noticed that new fuel injected supercars do this as well in the video game Driveclub. I know a video game doesn't seem like a reliable source, but I researched and found that the game creators simulate each car and the in-game driving experience very closely to their real life counterparts, even claiming they recorded the engine sounds of every car in real life to make sure that the in-game car audio reflects the sounds of the actual engine.
That given, I noticed that lots of the supercars/hypercars backfire a lot. Sometimes this happens during acceleration, but never during pure linear acceleration, mostly when coming out of a turn. This is usually indicated by somewhat subtle flames coming out of the exhaust and sometimes a soft popping noise. More prominently however, I've noticed it during deceleration, making two loud pops in quick succession accompanied by two quick bursts of intense flames shooting out the exhaust.
I've researched this online myself but I haven't found a complete explanation. I have also seen some explanations as why this happens in drag racing cars, but I wouldn't suspect the same explanation would hold for street legal cars since they are constructed and purposed differently. So, why do supercars backfire during acceleration, but not during linear acceleration? And why is the backfiring so much different during deceleration (specifically the two pops, louder noise, and bigger fire)?