gallons per hour stock vs. 9g90 injectors?

[DR]

hello everyone!! My wife told me I am a retard if I don't ask more questions!!  So here we go, I'm wanting to change to the fuel pro fuel filter, understanding a stock 6v92 uses 40 gallons per hour, if I change to 9g90 injectors does anyone know how much it will increse gallons per hour? We have a 84 eagle 6v92, looking at the smaller fuel pro fuel filter @ 50 gallons per hour. Thankyou for your help!! you can call me Retardo!! 

[Dallas]

DR,

It won't change the GPM at all since the fuel volume is constant from the tank into the rack and returns through the rteurn fuel line.
You will always transfer more fuel than your injectors can use.

IHTH

Dallas

[TomC]

I don't know where you got the 40 gallons an hour, but that would mean you would be getting less than 2mpg at 75 mph!  The rule of thumb is to take your horsepower output and multiply it by .055.  In this case, a 350hp 6V-92TA would use a maximum of 19.25 gallons/hour.  So climbing a hill at 35mph at full throttle you'd be getting 1.8 mpg-sounds about right
No matter what engine or transmission you have in your bus, you are in full command of what kind of fuel mileage you get.  In the trucking industry with 80,000lb trucks, we use-for each mile per hour between 55 and 65 you loose .1 mpg.  Between 65 and 75 you loose .15 mpg.  So the difference between going 55 and 75 can be 2.5 mpg!  Floor it all the time, cruising at 75 and above, is not conducive to good fuel mileage.  Here in Calif, I cruise at a nice even 58 mph where my engine is ticking over at 1900 rpm and I can get in the 6's (which is just fine by me. Considering my bus weighs 34,750lb with the car, that's like a Camry sized car getting 60 mpg!  Buses are pretty fuel efficient).  Good Luck, TomC

[DR]

Thankyou for your help, I don't know where I got gallons per hour unless it was in one of my manuals, just trying to use smaller filter @ $200.00 vs. larger filter @ $600.00. Dallas and Tom C. thankyou I know you both work with the big engines!!

[DrivingMissLazy]

I suspect it was total gallons per hour thru the fuel filter and fuel pump with the majority of it going back to the fuel tank. Only a small portion is tapped off to feed the injectors.
Richard

[Len Silva]

Just to add to the discussion.

If, for the sake of argument, 80% of the fuel is returned to the tank, then your filters could be 80% clogged before you would notice a performance lag.  If, as I understand it, the excess fuel flow is required for injector cooling, you could be harming your engine with a partially clogged filter even though it runs fine.

Which leads to the conclusion that 40 gph is reasonable.

This sounds like a statement, but it really is a question for those of you more knowledgeable than I.

Len

[Dallas]

Len,
In answer to your question, the answer is yes, the volume does decrease as the filters become plugged. However, on the back side of your fuel system is a restricting orifice that keeps a steady volume and pressure in the rack. As the volume drops, so does the pressure which in turn reduces the ability of the injectors to fill with fuel which reduces power, which reduces volume..... and on and on.
The rack will always move enough fuel to cool the injectors since the individual injector doesn't hold very much fuel at any one time.
To put it another way, if the injectors were that intolerant of low volume, you would be replacing the injectors every time you shut the engine down after a hard run.

IHTH

Dallas

[DR]

Thankyou everyone!!  DR