What causes a 'flame out' on overrun?
 

Newbie question here.
We all love to see it, when a 930 spits flames out the exhaust.
I assume it is excess fuel, but why?
Engine running very rich?
Do all 930's do it?
Do stock 930's do it or only modified engines?
Thanks
Ben

934's do it...935's do it.

My guess it's a modified 930 with the turbo reconfigured to belch flames out back.
(dumping unburned fuel/air into the atmosphere, ignited by the hot exhaust)

My 930 with a 1 bar spring used to spit a huge flame out the B&B muffler. I could see it in my rmy mirrors, but over time and mods, it doesn't any more. Not sure why..