Anybody know why?

Also for those of you who's wondering why I asked this, it's very simple. Afterburners. Most custom afterburners in SP are made out of VTOL engine, nozzle, BFE-150 (or other high powered jet engines), and some other low powered jet engines that are modified to be high powered. And those nozzles are for exhaust colors. I've made a Su-35BM in 1.10 and the Afterburners looked exactly how I wanted (light blue). And when I used it in 1.11, it became 90% dark blue (?) which I don't like. But I didn't change the exhaust color code so why?