I have my fuel pressure regulator between the electric pump, and the inlet to the fuel rail. The return comes off the bottom of the regulator, and there is a vacuum hose to reference boost to increase pressure under boost. At the end of the fuel rail is the pressure gauge. It all seems to work fine, but I cannot actually monitor fuel pressure while driving with the gauges I have. There might me a drop off of pressure under boost that I am not aware of.

In talking to a friend on Sunday, he suggested that the fuel pressure regulator should go after the fuel rail so that excess fuel gets sent back after the injectors instead of before. This is a guy who is drag racing very high HP applications, mosly SBC's. He contends that if you have an increased demand for fuel, the rail pressure might drop before the regulator can accomodate the demand, especially in a batch fire set up like mine.

What do you think?
Sam

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That's the way the Holley Cmmdr 950 has it in the instructions, the fuel rail is fed from the pump, and the regulator is on the back of the fuel rail, they also recommend a pressure gauge at that point so you can monitor how the last injector in the rail is doing fuel pressure-wise.

-D.Idiot

Sorry, I meant to posting this to the EFI section. My eyes don;t work tht great early in the morning. Thanks for the feedback. I might change this, depending on further comment.
Sam

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Definitely after the fuel rail not before.


"The fuel injectors require a regulated pressure to work properly. On an EFI system a bypass type pressure regulator is used. This means that any excess fuel is bypassed and returned to the fuel tank, which necessitates having a return line in the fuel tank. This return line must not just dump into the top of the tank, but go all the way to the bottom of the tank to keep from stirring up bubbles. The pressure regulator is mounted on the fuel rail somewhere after the pump and injectors. Throttle body systems have the regulator mounted in the throttle body. On some systems there is another device that looks like a pressure regulator mounted on the inlet side of the fuel rail, but it is a pressure damper. It dampens out the pressure fluctuations caused by the opening and closing of the injectors. Some pressure regulators can have their pressure adjusted but most cant. All EFI pressure regulators need to be referenced to the intake manifold vacuum so that they may adjust the fuel pressure to keep it constant across the injector regardless of the Amount of vacuum or pressure in the intake manifold."


Tom

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Nitrous cars are like old men on Viagra. Once the bottle is empty they are useless.
FJD

I'm using a regulator installed after the rail too. Carb-style regulators with one inlet, one return, and an outlet to the rail can work too, but I prefer one after the rail.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

see reg outlet barb at the end of the fuel rail

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Cheers!
Al T

i'm not gonna lie Al,
that is one sexy slant right there

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My Dart
GO VOLS!
It's not rocket science, we're just splitting atoms.

I should sayit is!. Where you getting spark from?
Sam

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Hate to go off topic, but yes, that is one sweet looking /6 Al! Is that a Ford T-Bird setup?

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DynoDave
1970 Plymouth Duster
1972 Dodge Charger Rallye
1977 Chrysler Cordoba
WPC # 12304