Fuel Pressure Regulator location

Gaz64 · #1 (**permalink**) 11-02-2009, 01:32 PM

Quote:

Originally Posted by Snakebit

Am I missing something here? I thought the regulator had to be mounted between the fuel pump and the carbs, and as close to the carbs as possible. The guage can be mounted after the carbs. If you mount the regulator after the carbs, then how can you adjust the fuel pressure?

The fuel pressure regulator is there to regulate the fuel pressure to the carbs, just under 3 lbs for Webers. You need a return line so the excess pressure can be bypassed.

A bypass regulator can be mounted before OR AFTER the carbs.

The regulator is not a restriction for fuel flow if after the carbs.

Mounted after, the carbs are getting fresh cool fuel at their inlets,
the regulator dumps the excess back to the tank just like EFI does but at a lower pressure. Mine runs at 3 psi.

Snakebit · #2 (**permalink**) 11-02-2009, 02:33 PM

So if my mechanical pump is putting out 7psi, and I place a regulator, with a bypass set at 3 psi, at the end of my Weber set up, all the carbs will be getting fuel at 3psi??? I would think the first carb would be getting fuel at 7psi???

Gaz64 · #3 (**permalink**) 11-02-2009, 03:07 PM

Quote:

Originally Posted by Snakebit

So if my mechanical pump is putting out 7psi, and I place a regulator, with a bypass set at 3 psi, at the end of my Weber set up, all the carbs will be getting fuel at 3psi??? I would think the first carb would be getting fuel at 7psi???

No, the regulator will send the excess back to the tank.
The pressure between the pump and the reg as seen by all the carbs SHOULD be what pressure the reg is set at. You could fit the gauge at each carb in turn to prove this.

I wouldn't do a bypass reg setup with a mechanical pump since the pump will always be "pumping" unlike when the mechanical pump "idles" when fuel pressure is up.

Swanny80 · #4 (**permalink**) 11-03-2009, 08:22 AM

I guess I could see with an electrical fuel pump and a bipass regulator it does not matter where you mount it, but for a mechnical fuel pump and a non bypass regulator, the regulator would have to be in front of the carbs to work properly. Wouldn't it? I have a non bypass regulator (mechanical fuel pump) BEFORE my webers and it seems to work fine.