2 Staged Fuel Pressure Regulators?

[fj1289]

Not to this point yet, but want to know if this is possible.  I'm thinking two external FPRs in series - first one at 43 psi and the second one set to higher pressure - maybe 70 psi.   Then add an electrical shut off valve to close off the return line on the first FPR and make the system then go to the higher pressure. 

Thinking this could allow a slightly smaller injectors for idle and low power - then higher pressure when dry nitrous is activated and have more fuel capacity available to tune with.   

[Rocketgeezer]

 It would seem like you may be able to do this with  one FMU, and use some sore of air pressure to boost the FMU to the higher pressure setting ???

[fj1289]

Reading up on how the FMUs operate is what gave me this idea.  I figured it would be like a "fixed pressure" FMU

[KZScott]

you could use an air regulator to put pressure to the fuel regulator. use the nitrous to do it. Tee the line to the jet, regulate it to a set psi, like say 30 and apply that to the fuel reg when the nitrous is on. fuel pressure goes up when nitrous is used.

[Rocketgeezer]

you could use an air regulator to put pressure to the fuel regulator. use the nitrous to do it. Tee the line to the jet, regulate it to a set psi, like say 30 and apply that to the fuel reg when the nitrous is on. fuel pressure goes up when nitrous is used.

This could work, but keep in mind when your FMU is operating at normal idle pres 40psi and when is get boost pres it go's up depending on the FMUs rate of gain, on a typical turbo application its like 6 to 1 so even 10 lbs to the FMU set up that way would give you 100 psi of pres, way to much, you need to get with a bike nitrous pro someone well experienced on running bikes on nitrous especially a dry system, if I were still playing with nitrous anymore I would look to Ryan Shinitz, as far as I know he's gone faster with nitrous than anybody else, and could most likely give you a set up that will work, and stay together

[KZScott]

i was talking about a regular 1:1 regulator. a na bike wont be using a vac/boost reference, so it would operate normally untill you apply the 30 psi(or whatever you select) of pressure to it. this way you only need 1 fuel regulator, and an air pressure regulator. say you have a set of 280cc inj at 43 psi, they would flow like a set of 365s at 73 psi