Just the OPPOSITE happens as the BOOST PRESSURE DROPS during SPOOL-DOWN, the SOOT gets blasted with a LEAN mixture as the TURBO winds down causing it to GLOW WHITE HOT as the FUEL is CUT OFF when the throttle is released . . .

Actually I get your point completely. When you get off the pedal the engine does indeed go lean but that is not what causes the "white hot glowing". What causes this is the immediate lack of BOOST!! Boost has a cooling effect beyond just stuffing more air into the cylinder. The higher the boost pressure, the better the cooling-to a point. Thats one of the reason intercooling works. It allows higher fueling rates while controlling combustion temperatures. Higher rpm will also lower EGT/combustion temperatures simply because there is more air passing through the engine and cooling it!! I have seen EGT's spike up when downshifting just as you describe because I have cut fueling and therefore boost momentarily for the shift to occur. The trick is to not run so hot that the EGT spike exceeds the limits of the engine when the shift happens or you have to get off the right pedal. The case you describe with "white hot glowing" has to be a very extreme example of a motor operating way beyond its design parameters. In order for this to occur the EGT's during operation must have been WAY WAY beyond safe limits to begin with. Which, if I may make my point again, would have been completely avoidable IF the operator had EGT/Boost instrumentation and knew what they were looking at. RT

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