Fuel line size, is bigger actually better?

[TurboBuRick]

Can bigger lines hurt big end fuel delivery? The train of thought is that bigger lines = more fuel, right?

If you were to change from stock size line to say -10 with the same fuel pump, are you really gaining anything? I am skeptical.

My thinking is, by increasing the line size, the fuel pump will have to work harder to deliver the same amount of fuel due to the increase of volume in the line.


Thoughts?

 

[1quick6]

In my opinion, larger fuel lines do not hurt at all with a "regular" fuel pump. Pumps have to overcome pressure, so putting a larger line in will not really have any effect given the pump remains the same. The difference comes into play when you have a large volume pump trying to push fuel through a line that is too small. It has to overcome the line restriction and it can't. Make the line larger to relieve line friction and you release the potential of the pump.

If you take two identical pumps and hook one up to a regular size fuel line and the other to a larger fuel line, the same amount of fuel will be pushed through both lines. The pump connected to the larger line won't try to move more fuel just because it has the potential to. Pumps see pressure, not weight. Just because there is more fuel to move in a bigger line doesn't mean the pump has to work harder to do it.

 

[TurboBuRick]

Thanks for chiming in 1quick6. I have doubts because fuel volume drops as pressure increases. So down low, I do agree with you but start to demand pressure and things change.

Maybe I'm out in left Field with my way of thinking but I plan to run some experiments to see for myself.

Where you at Chuck Leeper? Like to get some of your insight on this.

 

[DR BOOST]

Thanks for chiming in 1quick6. I have doubts because fuel volume drops as pressure increases. So down low, I do agree with you but start to demand pressure and things change.

volume only drops if the pressure increase is due to a restriction. And this is usually due to the fact that pumps operate better with less afterload.

volume is increased along with pressure if pumping force is increased.


there is a lot more involved than what has been stated.

 

[DR BOOST]

for 99% of the buicks out there, a 1/2" line (-8) is more than enough for fuel delivery.

 

[TurboBuRick]

Well hello there Dr. boost. Glad you could make it.

I will agree on the 99% thing. The rest will take some testing to be convinced.

Like you said, there is allot more involved.

 

[JayC]

for 99% of the buicks out there, a 1/2" line (-8) is more than enough for fuel delivery.

+1

We have -6 lines feeding each injector on the race car. I guess that puts us in the 1%

 

[Chuck Leeper]

Once the line is full, & the volume of fuel used remains the same, the line could be 1" and the pump would not see the difference.

"volume only drops if the pressure increase is due to a restriction. And this is usually due to the fact that pumps operate better with less afterload."
The "Afterload" you mention, is anything after the pump outlet, such as the regulator. Some intank pumps have a regulator, some don't. reg location is not a factor of significance
Look at the pump mfgr's flow charts. They will usually show flow, based on:
Voltage.
Op pressure.
Look at the chart. You will see the flow drop as the volts go down, and/or the psi goes up.

Bottom line is the engine fuel requirements can "outrun" a pump's ability to keep up....The fact this is done w/ a 1/2" line, or a 2" is irrelevent.

 

[TurboBuRick]

Bottom line is the engine fuel requirements can "outrun" a pump's ability to keep up....The fact this is done w/ a 1/2" line, or a 2" is irrelevent.

Thanks Chuck,
I value your experience my friend. I'm going to go ahead and close this thread because there is no more debate.

P.S. I fixed the spelling in you name in my other post. Cheers!