That fuel pump arrangement would make it easy to recirc right back into the tank. An overcapacity pump behind a regulator is the best way to maintain constant pressure in a variable demand system, it's almost guaranteed they're doing it that way. The single hose coming out will be downstream of the regulators so the pressure and supply are already controlled in the hose.
Let's reason through the supercharger question. Unlike a turbocharger, a supercharger is locked to engine RPM due to its belt drive. But at any given RPM, the power demand (and thus fuel demand) can vary widely depending on engine load. It takes very little fuel to spin up an engine to (say) 3000 RPM if there's no load on it, yet that same 3000 RPM takes 10+ GPM when ballasted and generating a good surf wave. That 10+ GPM of fuel requires a proportional amount of airflow to keep the ratio at 14.7. Yet the RPM's, and therefore the speed of the supercharger, are the same. If the RPM's are the same but we're demanding far less work out of the engine then it needs less fuel.
The injector pulse widths can narrow to handle the reduced fuel demand, but what about the air? The belt is still spinning the supercharger at the 3000 RPM rate, which means the supercharger is generating the same amount of air volume at 3000 engine RPM whether the engine is burning a little bit of fuel (no load) or 10 GPM (surfing). To maintain the ratio, that excess air has to be vented somewhere. It cannot be routed through the engine or the fuel mixture will be hyper-lean to the point of stalling.
Based on this, it's virtually certain that some sort of waste gate exists.
You're correct, but I think that's approaching it backwards. The controlling factor is "how much power do we need out of the engine?". Power comes from fuel. So power demand drives fuel demand, which in turn drives air demand to maintain 14.7. It's not a question of "we have too much air coming in, open up the injectors". It's "we need this much fuel to satisfy the power requirement, let in the right amount of air to maintain 14.7".
If it went the other way - change the injector pulse widths to match airflow - then you would have a runaway condition on a lightly loaded engine. As RPM's increase, airflow (supercharger running at a fixed belt ratio) would increase, so fuel would have to increase, which would generate more power and thus raise RPM's even more, which would spin the supercharger faster and increase the airflow, and.... Without sufficient load on the engine the RPM's would go open loop.
Let's reason through the supercharger question. Unlike a turbocharger, a supercharger is locked to engine RPM due to its belt drive. But at any given RPM, the power demand (and thus fuel demand) can vary widely depending on engine load. It takes very little fuel to spin up an engine to (say) 3000 RPM if there's no load on it, yet that same 3000 RPM takes 10+ GPM when ballasted and generating a good surf wave. That 10+ GPM of fuel requires a proportional amount of airflow to keep the ratio at 14.7. Yet the RPM's, and therefore the speed of the supercharger, are the same. If the RPM's are the same but we're demanding far less work out of the engine then it needs less fuel.
The injector pulse widths can narrow to handle the reduced fuel demand, but what about the air? The belt is still spinning the supercharger at the 3000 RPM rate, which means the supercharger is generating the same amount of air volume at 3000 engine RPM whether the engine is burning a little bit of fuel (no load) or 10 GPM (surfing). To maintain the ratio, that excess air has to be vented somewhere. It cannot be routed through the engine or the fuel mixture will be hyper-lean to the point of stalling.
Based on this, it's virtually certain that some sort of waste gate exists.
So after all that babble....Im still sticking to my guns purely on the engine side that more charged air(boost) is going to equal a longer injector pulse width to stay 14.7
If it went the other way - change the injector pulse widths to match airflow - then you would have a runaway condition on a lightly loaded engine. As RPM's increase, airflow (supercharger running at a fixed belt ratio) would increase, so fuel would have to increase, which would generate more power and thus raise RPM's even more, which would spin the supercharger faster and increase the airflow, and.... Without sufficient load on the engine the RPM's would go open loop.
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