The pressure regulator we are discussing is intended to be installed immediately behind the engine. The regulator takes hi (and variable) pressure fuel as in inlet, and regulates it to a rather constant pressure (outlet) to your engine. I believe my system is very much like the Paul Walker B-17 set up.
In a multi-engine model, say a twin engine Tigercat (or a 4 engine B-17) the idea is to:
1) Have a single hi pressure single fuel tank mounted somewhere convenient, say in the fuselage.
2) Have each tiny regulator right behind each engine to provide regulated pressure to that engine.
Due to the centrifugal force of CL flying, the fuel pressure at the regulator inlet will be VERY different at each engine. One regulator is inboard of the fuel tank, the other is outboard. By have the regulators behind each engine, the engines see relativity constant pressure to the spray bar and the motors now becomes immune to variations in pressure feeding the regulators.
I suspect that muffler pressure is not adequate to pressurize the fuel tank in a multi-engine system in the Tigercat configuration because the fuel head difference between inboard and outboard is way more than muffler pressure. I used a big combat fuel bladder. Perhaps an inline set up could use muffler pressure, but I don’t have experience doing that.
Hope this is helpful.
Jim Hoffman