Fuel Pump Voltage increase methods
08-24-2008, 10:18 AM
#7
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The pump is not set to deliver any specific pressure, that is set by the fuel pressure regulator.
Basically, the capacity of a pump is measured in terms of volumes vs. pressure. A larger pump can deliver either a larger volume of fuel at the same pressure, or the same volume of fuel at a higher pressure (or both, along a finite continuum.) So as the FPR calls for more pressure, the pump is able to keep up with demand.
For example, here is the plot from a Walbro 155:
And here's the plot from a 190HP:
(Source and credit: https://www.miataturbo.net/forum/showthread.php?t=4288)
Basically, the capacity of a pump is measured in terms of volumes vs. pressure. A larger pump can deliver either a larger volume of fuel at the same pressure, or the same volume of fuel at a higher pressure (or both, along a finite continuum.) So as the FPR calls for more pressure, the pump is able to keep up with demand.
For example, here is the plot from a Walbro 155:
And here's the plot from a 190HP:
(Source and credit: https://www.miataturbo.net/forum/showthread.php?t=4288)
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08-24-2008, 10:24 AM
#8
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So looks like I'll still need to mess with the stock regulator to consistantly hold a higher pressure under boost. I have full ECU control, and trying to make a "cheap" but reliable road racing set up. Weighing the cost of larger injectors vs fuel pressure increase methods with the stock 230cc injectors. Boost is limited to 6 psi, 7200RPM rev limit.
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08-25-2008, 06:43 PM
#13
So looks like I'll still need to mess with the stock regulator to consistantly hold a higher pressure under boost. I have full ECU control, and trying to make a "cheap" but reliable road racing set up. Weighing the cost of larger injectors vs fuel pressure increase methods with the stock 230cc injectors. Boost is limited to 6 psi, 7200RPM rev limit.
AFPR setup might not be so reliable if WOT is maintained for long periods of time. Specially since you're adding an additional mechanical component in the loop, plus the injectors, fittings, lines, and clamps are under higher continuous pressure than they were designed for. Better option is to get larger injectors since you already have an ECU. Is this a MAF or a speed-density based ECU?
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