fuel: how far will -6 get me?

[terefic181]

Hi guys,

I guess I'm working on sematics at this point. I'm trying to substantiate my original statement above that fuel pressure goes down with larger lines. Nothing to do with the consumtion just pressure at the pump. So here goes....

I don't disagree with the consumption issue at all. It remains the same. That's not my point.
I don't disagree with pressure being different within the line at any given point (the pressure is the same throughout the system).

So what your saying is that a fuel pump can push any amount of fuel through the system at the same pressure, no matter what diameter, or say length fuel line. A larger amount of fuel in the system puts no more work on the pump? Is that correct?


What I'm saying is that the pressure the pump is able to produce is less due to the mass of extra fuel it's pushing (back pressure if you will).

Anyone agree with this?

Thanks guys.

 

[Blue92]

I disagree, the pump is rated to flow a certain amount of fuel at a certain pressure. And, the pump will have sufficient power to fill a larger line and still flow that amount at that a set pressure. The only way that the pump would not be able to build pressure, would be if the consumption did not allow it, i.e. an open ended hose.

 

[kpt4321]

The size of the feed line does not effect the fuel pressure in itself, no way. Examples of a garden hose simply don't make sense. If you have a regulator on the end of a garden hose, then you will get the same pressure in the hose regardless of the internal volume.

Situations when you are maxing out one component of the system or another are not relevant, simply because that introduces too many variable to make solid points without defining everything.

 

[terefic181]

No takers ....eh?............

Well ...maybe I just have a hard time visualizing the pump having the ability to hold pressure at a constant with an increased load till it finally no longer can keep it and it falls to zero. In other words with no reduction pressure curve in between full pressure and zero.

The extra load of fuel and a reduced pressure curve is kinda what I was basing my assumptions on.

Oh well....We'll leave it there gentlemen...

Thank you for a lively and civil discussion, and I look forward to talking with you in the future.

Tom

 

[Kevin Jewer]

And that my friends, is how you have a mature discussion about a topic, read and learn Poeple can disaggree and still get along. Well done.

 

[Mirage2LTurbo]

If you have a -6 line and a -12 line, you are going to have to flow twice as much volume in the -12 to maintian the same pressure. If you put a restrictor at the end of the line, it is going to increase pressure in the line. Why else would some put inline reducers on their oil feed lines? To REDUCE pressure after the reducer because it decreases the volume of oil that can pass through.

 

[Kevin Jewer]

In a closed, pressure regulated system, the flow will be the same in the 6 or 12 lines.

 

[Mirage2LTurbo]

In a closed, pressure regulated system, the flow will be the same in the 6 or 12 lines.

Correct, the fuel pump only has to supply enough fuel to overcome what the injectors expend.

 

[Blue92]

Again, thanks for the lively, mature discussion guys.