FUEL REGULATORS

badboygem · tinkerer Joined: 31 Aug 2002 Posts: 132

i am wondering how those malpassi rise rate regulators work.....does anyone have one so they can tell me??

i want to know do they just adjustably set an overall pressure of say 14psi which doesnt change the whole time the engine is running. or do they have a sensor to say the coil or distributer so that they can vary fuel pressure when the engine revs.

the reason i ask is that if you have a blow thru turbo set up on a carby and u run 8 pound of boost...u might run say 12psi of fuel pressure so u still have fuel pressure when it comes on boost. BUT what about when its not on boost. does that mean itll be pumping 12 psi thru the carb and running rich.

any help is appreciated
cheers

rust3 · backyard mechanic Joined: 04 Feb 2002 Posts: 971

ive got one but its for efi, i think carbie and efi ones are different. the efi one you set to a pressure and it stays at that pressure not matter what revs you are doing

Loz · backyard mechanic Joined: 05 Oct 2001 Posts: 943

both rising rate regulators for efi and carby run of manifold vacuum. ie the more you rev the more vacuum and the more fuel pressure. Generally it rises at a rate of 1:1 of manifol pressure change to fuel pressure. The efi ones do need o be set at the base pressure though.

Loz

badboygem · tinkerer Joined: 31 Aug 2002 Posts: 132

ok when you rev ur engine....under load....u get very bad vacuum right?? so when you get boost this would just push it into the positives right?? does this mean that a riseing rate regulator is exactly what i need, but i still dont understand how it can be a couple of psi above the boost pressure??

Nick_H · tinkerer Joined: 12 Oct 2001 Posts: 76

a rising rate regulator will allow the fuel pressure to rise when vacume is at its lowest and under boost it has a pipe that is connected to your manifold.It will have a adjuster to set the fuel pressure and you will need a fuel pressure guage to get the settings right.you will also need a fuel pump which is able to give around 16 psi would be a good start too. holley blue or black will do that job ok. when idling the vacume is hi so the fuel pressure is lowered because the fuel bowl in the carby is easly filled and a needle and seat will really only handle about 6 to 7 psi.
when under boost youll need as much fuel as u can stuff in there the fuel bowl will not fill to its maximum so the needle and seat will not be affected.