Carb plumbing

[Zvoiture]

Forgive the ignorant question, but I am shopping for regulator/pump/filter for my new engine and Mikunis and am a bit confused how carbs work.

On my FI motor, it is: Tank--Pump--Filter--Rail (injectors)--Regulator--return to tank. So, as I understand it, the system is 'pressured up' and any excess pressure/unused fuel is vented off throught he regulator back to the tank.

Now on a carb system, the regulator has to be before the carb, right? The pump makes somewhere between 7 and 15 and the carbs only need 3-3.5, so regulation has to come BEFORE the carbs, right? So you need a pump that even though you are using a large volume (high RPM) it can keep the pressure up at the same 3-3.5. Is there a return out of the regulator back to the tank? Or does the pump just run staticly 'against' the regulator even when nothing is flowing (electric pump--on all the time). All of the regulators I am looking at have at least two output ports. Do you just cap one or does one become a return? If you bought a regulator with three outputs, could one go to each carb?

So it is Tank--(filter here?)--Pump--(or here?)--Regulator--Rail(carbs)--?

steve

[panchovisa]

I belive that for your new Mikunis you will want an electric pump with built in by-pass (Holley has it) then filter, then regulator, then fuelrail with three outlets (or plumb carbs in series). You could also tee the pressure line out of the regulator and run the fuel through a loop to the carbs connected in series.

The regulaters (Holley) have three ports: line in/ regulated pressure out/ and addition port for mechanical (plumbed) fuel pressure gage, or electric gage sender.

If you are using a fuel cell with two pickups/outlets you must put a pump on each outlet. After pumps you may tee lines into one filter. If you don't want the expense of two pumps then use only one pickup and cap the other.

Pancho