Hi All, Second flight in the airplane…I was off to do a test flight with red yarn on my canard, main wing, and winglet to do some benchmark stall and performance testing prior to installing Vortex Generators (you can see a bunch of red yarn pieces taped to the left wing and canard) and one of my silicon turbocharger couplings popped off and my Manifold Air Pressure immediately dropped from 42 inches to 29.3 inches causing my engine’s Effective Compression Ratio to also drop from 12.0 to 1 compression down to 7.0 to 1 compression (in a millisecond) and therefore causing my 12.0 to 1 happy face to turn into a 7.3 to 1 sad face at 200 feet AGL. Someone at the airport caught it on youtube, I wont bore you with the return to landing flight details (I did do a write up on the YouTube video page if you are interested… https://www.youtube.com/watch?v=Wslr5dVQcPU Yes I expected the engine HP to drastically reduce if the turbocharger pipe popped off however the amount of drop in HP was really surprising and the black smoke as seen inn the video was also surprising...hence the question in this post...The following post is what I THINK the reason for the drastic drop in HP and black smoke...however...if someone familiar with turbocharging systems can PLEASE back up my thinking or flat out correct me I would be most grateful... The engine is a TIO-540 with 7.3:1 compression pistons and with 42 inches of MAP the Effective Compression Ratio of the engine is more like 12:1. Using a generic horsepower calculator that I found online, I came up with the following numbers: Engine Displacement (CID) is 540 Engine Revolutions Per Minute is 2700 At 12.0 compression ratio Computed Engine HP is 348 At 7.3 compression ratio Computed Engine HP is 194 So at first glance 194 HP should be plenty to make the airplane fly… The way the turbocharger system on my airplane works…stolen from a Bellanca Viking and pretty much all of the airframe makers during that era used a similar system…is the exhaust gasses pass through the impeller of the turbocharger and connected to that same shaft is a compressor. The compressor pumps air into the intake system. Directly upstream of the Bendix opening is a fitting that taps air pressure and this air pressure is fed to the wastegate controller. The job of the wastegate controller is regulate the air pressure being supplied to the Bendix to 42 inches of mercury measured as Manifold Air Pressure (MAP). If the air pressure drops below 42 MAP then the wastegate controller tells the exhaust wastegate to close farther and more exhaust gasses are forced into the turbocharger impeller and this will pump up more air. If the air pressure above the Bendix is more than 42 MAP then the wastegate controller tells the exhaust wastegate to open so that exhaust gasses will be dumped out before they can forced through the turbocharger…that is why my airplane has two exhaust pipes…the small one is the wastegate exhaust pipe and the larger one is the turbocharger exhaust pipe. So why so much more smoke and so much less power? The intake air pipe coupling that popped off was the coupling just before the last pipe that leads to the Bendix. When it popped off the forced air supply from the turbocharger no longer was being shoved down the throat of the Bendix but instead it was being dumped into the engine cowling and that is why my indicated MAP dropped from 42 MAP to 29.3 MAP. I heard the pop and the air whooshing sound however at that point I could tell if the noise was coming from the engine compartment or from my shorts. Since the wastegate controller saw the drop in pressure upstream of the Bendix it then told the exhaust wastegate to close as far as possible so as to drive more gasses into the turbo in an effort to bring the MAP back up to 42 inches. When the wastegate closed completely, all of the exhaust gasses were forced through the turbo and this created a bunch of exhaust system backpressure. Since the mechanical compression ratio of the engine is only 7.3:1, the low compression pistons do not produce a great deal of power and therefore do not produce a great deal of exhaust pressure and since all of the exhaust gasses are now being forced into the turbocharger that “clogged up” exhaust system makes the situation worse so that is the reason for the great loss of power and my guess is that the engine was producing much less than 194 HP. I’m sure the turbocharger was spinning much faster than it should so I first thought that it was oil being forced past the seals and burning that was causing the smoke however oil burning would be blue and this smoke was black so that should be an excessively rich mixture. But because the Bendix was just seeing 29.3 MAP it should have simply reduced the fuel flow being pumped up to the injectors accordingly…however…since the fuel injectors on a turbocharged engine have a shroud around them that is normally pressurized by a pipe system that taps the same 42 MAP air (this is needed to atomize the fuel being squirted out of the injectors)…and since those hoses were still intact…and since the Bendix was now sucking air as opposed to the normal condition where the air is being forced into the throat of the Bendix…my guess is that the negative air pressure from the pipes before the Bendix was sucking air down from the fuel injector nozzle shrouds and that caused the injector nozzles to no longer atomize/ spray the fuel but instead to just squirt/dribble the fuel into the engine and this would cause the engine to burn the same volume of fuel but much less efficiently. Does anyone who has experience with aircraft turbocharger systems have any thoughts to share…other than to tell me to ensure that the silicon couplings are clamped down more tightly??? I am going to make sure that the ends of each pipe has a larger lip on it…don’t want that to happen again…Just say’in… THANKS!!!