Fuel pressure and fuel mileage

M

Mofugra

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I'm curious is there a correlation between fuel pressure and mileage. I realize there are many factors that have a large impact too, but has anyone done any testing to see if say 20psi at idle will net better mileage then say 40psi. I have one of those York tech ofv valves and I was thinking about making some adjustments to get better mileage if possible that is.
Thoughts??

Oh it's a 215pump incase people want that info.
 
More pressure = better

Fuel pressure drops when your fuel filter gets clogged/dirty. And guess what? your mileage goes with it.

Final Summation: More pressure = better mileage!

Spence
 
Not to sound too much like DTanklage but.....

YOUNG GUNS15 said:
More pressure = better

Fuel pressure drops when your fuel filter gets clogged/dirty. And guess what? your mileage goes with it.

Final Summation: More pressure = better mileage!

Spence
Click to expand...


Have any data to prove this?


Fuel pressure is the indicator we use for fuel volume. When the filter plugs your volume decreases and causes a drop in pressure. As long as you are within the acceptable working parameters of the injection pump, variations in pressure for the same volume will not have much effect. Lack of volume is the main reason you lose performance.


I have run my 180GPH FASS at 30psi, 35psi, 40psi, and 60psi and never noticed a difference.
 
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Whiteknight. Were those observations made with an exteral fp regulator or with the stock ofv in place. My understanding was that at higher pressures caused by ofv modification the ofv would allow for higher psi and thus more volume to flow through the pump and less to be returned to the tank. My though is that when strictly going for mileage a lower pressure would result in more milage.
 
External regulator, post injection pump.

An OFV is just a regulator, it works the same way a aftermarket external regulator does. They are both simply relief valves.


Where do you think the extra fuel is going? Liquid is not nearly as compressible as a gas, a higher pressure doesn't mean denser fuel.

Increasing the spring pressure in the OFV or regulator does a few things, one of these things is it increases the pressure that the fuel pump must create before it will allow any fuel to return to the tank (the cracking pressure if you will) For a volume starved system this is very important.
 
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White Knight said:
Have any data to prove this?


Fuel pressure is the indicator we use for fuel volume. When the filter plugs your volume decreases and causes a drop in pressure. As long as you are within the acceptable working parameters of the injection pump, variations in pressure for the same volume will not have much effect. Lack of volume is the main reason you lose performance.


I have run my 180GPH FASS at 30psi, 35psi, 40psi, and 60psi and never noticed a difference.
Click to expand...

I dont have any data. But when you replace the clogged filter, pressure goes back to normal and your mileage improves. I worded it wrong and it sounds like Im claiming if you increased your pressure from 35psi-40psi you would see mileage gains. Which you wont, sorry for the misunderstanding!

Spence
 
yeah, but there's a big difference between a clogged filter causing fuel pressure to drop to zero or less and 20psi vs. 20psi vs. 40psi

I'm betting you see zero increase in fuel mileage
 
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