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Morning Gents, I'm going to be plumbing in a regulator today for my single turbo Ls1. My plan is to use my walbro 255 I have in the tank, -6 an lines, a 10 micron filter inline after the pump feeding the drivers side speed inc rails. Then out of the pass side rail to the reg. Out of the reg back to the tank. Can I install the guage off the rail (leave it where it is) or do I need it on the regulator. See the pic of my current set up and what I'm thinking about. Let me know if this will work please.
My gauge was where the one in the pic is-I used a boost only line to the reg,
I didn't want it to see vac. so I could just start at 43 lbs
I tapped into the pipe right out of the turbo. People do it diff., this worked fine for me
The normal place for the signal for the FPR is the intake manifold, but you could choose to do it differently if you wish.
can I tap off of the back of the intake manifold where my boost gauge is connected to? Same spot as the map sensor I don't have power brakes so I could reduce that and connect there?
Just keep in mind if you use a vac/boost source for the reg, if you set your base pressure with the engine off, it will drop below that 3-5 lbs with engine vac, or you can choose to set it with the engine idling-liquid filed gauges can read off when hot also.
Just keep in mind if you use a vac/boost source for the reg, if you set your base pressure with the engine off, it will drop below that 3-5 lbs with engine vac, or you can choose to set it with the engine idling-liquid filed gauges can read off when hot also.
This is true. I set mine to 60 psi engine off and found it was dropping to 50 during vacuum/idling. Kinda makes me want to change how its hooked up.
Apparently if using a manifold source for signal, you scale the tune for even flow across the vacuum range, because the FPR is reducing pressure under vacuum. So you set pressure with the engine off, and set flow evenly across the tune and let the FPR do the work. Or you could boost reference only, and leave the normal style settings for injector flow rate (which are vaccum to 0 psi only) and let the FPR do the work under boost only.
The best way for normal street cars is to let the vacuum pull the pressure down, thus relieving strain on the fuel pump. The pump life may be improved by keeping pressure lower.
The best way for normal street cars is to let the vacuum pull the pressure down, thus relieving strain on the fuel pump. The pump life may be improved by keeping pressure lower.
Alright, I’m calling you out. Please explain how a vacuum signal to a fuel regulator changes the fuel pressure output of an electric fuel pump (“by relieving the strain on the pump”) providing the voltage to the pump remains the same? Second part, please explain how a vacuum/boost referenced fuel regulator works.
Alright, I’m calling you out. Please explain how a vacuum signal to a fuel regulator changes the fuel pressure output of an electric fuel pump (“by relieving the strain on the pump”) providing the voltage to the pump remains the same? Second part, please explain how a vacuum/boost referenced fuel regulator works.
Fuel pressure is a measure of restriction. If you allow vacuum to lower fuel pressure at the rail with a vacuum referenced FPR, then the lower pressure makes it easier on the pump. GM did this for years. The reverse is true under boost. This is done to maintain constant pressure at the injectors due to boost. GM did this for years. That's how I understand it...
Fuel pressure is a measure of restriction. If you allow vacuum to lower fuel pressure at the rail with a vacuum referenced FPR, then the lower pressure makes it easier on the pump. GM did this for years. The reverse is true under boost. This is done to maintain constant pressure at the injectors due to boost. GM did this for years. That's how I understand it...
Andrew
Kinda wanted him to explain it, but some ecus reduce voltage to the pumps at low demand conditions. What about systems that maintain constant voltage to the pump(s)? What about return style regulators? Don't tell me that the outlet pressure of the pump changes (hence reducing the workload) because you have a vacuum line to the regulator. You know better than that.
09-23-2017, 10:01 AM
Boost referenced FPR 
