Help me understand a bypass regulator location

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SGBARRACUDA

SGBARRACUDA

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Having a extensive knowledge on hydraulics, (33 years a firefighter,19 years a driver engineer), how can placing a pressure regulator after the carburetor, limit the pressure a carb. sees?
If you look at the diagrams on the Holley PDF, if you look at figure 3 how is this set up going to limit the amount of pressure the carb. sees? I mean in figure2 I can see "how it works."


[ame]http://documents.holley.com/199r7914-3rev6.pdf[/ame]
 
It limits the pressure in the entire system before the regulator. Just imagine the carburetor not even being there. Just imagine the fuel line being solid all the way to the regulator. The carburetor being in the circuit has zero effect on the system in terms of regulated pressure. It is "just another" section of fuel line as far as the regulator knows.
 
A Holley Blue pump says it pumps 14 PSI. The 12-803 BP regulator is adjustable from 4-9 1/2 PSI. With the regulator mounted after the carb. Wouldn't the carb see 14 PSI until the regulator than it would be what ever the regulator was set at after? I guess I'm a little thick in the head. I just don't see how set up like this that the carb would see the same pressure as post regulator?
 
SGBARRACUDA said:
A Holley Blue pump says it pumps 14 PSI. The 12-803 BP regulator is adjustable from 4-9 1/2 PSI. With the regulator mounted after the carb. Wouldn't the carb see 14 PSI until the regulator than it would be what ever the regulator was set at after? I guess I'm a little thick in the head. I just don't see how set up like this that the carb would see the same pressure as post regulator?
Click to expand...

No. The carburetor sees whatever pressure the regulator lets it. Think of my example above. It does not matter that the carburetor is a carburetor. It is just another section of line.
 
I think where my thinking has gone astray is, I'm forgetting that the amount bypassed is not a set amount. The amount bypassed depends on demand? So when the pump is on the amount bypassing is anything above the regulator setting, right? And same goes when the the engine is running, weather idling or WOT. The amount bypassing varies right?
 
Pressure and volume are two different things. The pressure is maintained no matter what the volume of fuel passing through the regulator is.

And why does it not matter where the bypass regulator is? Because all it does is bleed off excess pressure in the entire fuel system, and sends the bled off fuel back to the fuel tank.
 
SGBARRACUDA said:
I think where my thinking has gone astray is, I'm forgetting that the amount bypassed is not a set amount. The amount bypassed depends on demand? So when the pump is on the amount bypassing is anything above the regulator setting, right? And same goes when the the engine is running, weather idling or WOT. The amount bypassing varies right?
Click to expand...

YES. That's correct. The return amount must vary since all of the fuel is not used and the amount of use itself varies. The only constant is the regulated fuel pressure......more or less. While it Is considered constant, it can vary a small amount, but not much.
 
RustyRatRod said:
YES. That's correct. The return amount must vary since all of the fuel is not used and the amount of use itself varies. The only constant is the regulated fuel pressure......more or less. While it Is considered constant, it can vary a small amount, but not much.
Click to expand...

Thanks for straightening my brain out.
 
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