5.0 conversion fuel pump

[Guy Groves]

For those of you that have done a conversion...

Are you using the stock fuel pump from the 4.0, or have you replaced it.

What pump have you used?

Any installation comments?

For those using the stock 4.0 pump, Any fuel delivery problems and is your engine modified?

Thanks
Guy

 

[Speedfreak]

With the conversion I have already completed, I used the pump from a Mustang. I pulled the sending unit and pump assembly out of the Explorer and replaced the pump only with the Mustang unit. For my own conversion I will be using a 155lph aftermarket pump for fuel supply, available at any high proformance parts store.

 

[asp84]

I used my stock 4.0 Explorer Fuel Pump ('91) with my 1992 5.0 H.O. V8. Absolutely no problem at ALL!!!!

Although my 92 5.0 is bone stock..........T-bird motor being ran on a 1990 MUSTANG 5.0 computer system.

If you plan to turn your 5.0 in to a racign machine, you should definately consider the stang fuel pump.

Good Luck!

Al

 

[Speedfreak]

I stock pump will handle the fuel requirements at low rpms but will begin to inadequate above 3500prm. The stock pump is only rated at 65lph while the Mustang pump is rated at 88lph for the older ones and 95lph for the newer ones. If you run the engine lean even in stock form for any length of time you can cause major internal damage. I recomend replacing the pump to be on the safe side. Too much fuel will be bypassed by the pressure regulator but too little fuel is the equivalent of dumping sand in to the intake tracted and hoping it goes through the engine without causing damage.

 

[asp84]

Speedfreak......... I am interested in seeing the calculations of fuel usage as it refers to RPM.........

Thanks

Al

 

[Speedfreak]

I have the specific fuel comsumption/brake horsepower formula somewhere, I'll have to dig it up.

The problem with the smaller pumps mainly is the inability to maintain the pressure of 40 psi when the engine is at higher rpm. The pump flows more then enough to feed the engine, but it needs to feed enough to maintain the critical psi needed for the injectors to deliver the correct amount of fuel for the longer duty cycle. At full throttle you can have the 8 injectors running at 85 to 90% duty cycles, and at 100% they flow 19lbs of fuel per hour. If the psi isn't meet then you can have a problem. You may not even notice it until you are going up a long hill under a good load, when suddenly it sounds like marbles in the engine.

I learned the hard way when I burned 2 exhaust valves in my SVO Mustang going up a steep hill. I found that even the stock pumps didn't supply enough fuel for the little 2.3L turbo engine. I very quickly put a fuel pressure gauge and a 155lph pump in.

 

[asp84]

Speedfreak,
...........point taken. I'll have to add that to my list of future upgrades

For now though....... I barely get over 3000 RPM.........and spend a lot of time in Overdrive, where I turn low RPM's

Thanks for the good info


Al

 

[Sandy]

When I did my Ranger (2.9) to 5.0 conversion I used and am still using the stock fuel pump.
Yes the engine is a stock 92 5.oL froma stang and yes I do not drive it above 4000 a lot but the pump has surficed for my application.
What application you ask, well I do trail runs, mud runs and street runs, the engine seems to run well.

Start off with the stock pump, if for what ever reason you feel there is not enough gas getting to the engine then look into ungrading.

Good Luck,

 

[Guy Groves]

Thanks for the information,keep it coming....

I have started an Excel spreadsheet to perform typical auto calculations. So far I have only done some basic calculations for air filter surface area, and fuel pump sizing.

I will be adding more as time goes on, send in requests and sources for formulas. I am curently using "mustang math" as my source.

Guy
guygroves@earthlink.net

 

[Speedfreak]

The Mustang Math is also my source of infomation. I just cann't find it. I hope I didn't lose it the last time I moved.