What Fuel Pump To Use On Stock 91 5.0

my fuel pump died this morning. the car is stock right now but i will be getting new heads cam and intake in about six months. my question is can i install a 190 or a 255lph right now since i got the tank out or is it going to be too much strain on the larger than stock pump for the next six months untill the new h/c/i is installed. any suggestions please.
 
  • Sponsors (?)


Don't waste your money on a monster pump if you aren't using NO2 or pressurized induction: 155 LPH will be plenty.

Copied from the FORD RACING PERFORMANCE PARTS catalog:

PROPERLY SIZING FUEL SYSTEM COMPONENTS


Fuel Pumps
The following information is presented assuming the above information has been taken into consideration regarding BSFC, fuel pressure and specific gravity of the fuel being used. Most fuel pumps for electronic fuel injection are rated for flow at 12 volts @ 40 PSI. Most vehicle charging systems operate anywhere from 13.2v to 14.4v. The more voltage you feed a pump, the faster it spins which, obviously, will put out more fuel. Rating a fuel pump at 12 volts then, should offer a fairly conservative fuel flow rating allowing you to safely determine the pump’s ability to supply an adequate amount of fuel for a particular application.

As previously mentioned, engines actually require a certain WEIGHT of fuel, NOT a certain VOLUME of fuel per horsepower. This can offer a bit of confusion since most fuel pumps are rated by volume, and not by weight. To determine the proper fuel pump required, a few mathematical conversions will need to be performed using the following information. There are 3.785 liters in 1 US Gallon. 1 gallon of gasoline (.72 specific gravity @ 65° F) weighs 6.009 LBS.

To be certain that the fuel pump is not run to its very limit, which could potentially be dangerous to the engine, multiply the final output of the fuel pump by 0.9 to determine the capacity of the fuel pump at 90% output. This should offer plenty of ‘cushion’ as to the overall “horsepower capacity” of the fuel pump.

To determine the overall capacity of a fuel pump rated in liters, use the additional following conversions:
(Liters per Hour) / 3.785 = Gallons
Multiply by 6.009 = LBS/HR
Multiply by 0.9 = Capacity at 90%
Divide by BSFC = Horsepower Capacity
So for a 110 LPH fuel pump:
110 / 3.785 = 29.06 Gallons
29.06 x 6.009 = 174.62 LBS/HR
174.62 x 0.9 = 157 LBS/HR @ 90% Capacity
157 / 0.5 = 314 HP safe naturally aspirated “Horsepower Capacity”

Safe “Horsepower Capacity” @ 40 PSI with 12 Volts
60 Liter Pump = 95 LB/HR X .9 = 86 LB/HR, Safe for 170 naturally aspirated Horsepower
88 Liter Pump = 140 LB/HR X .9 = 126 LB/HR, Safe for 250 naturally aspirated Horsepower
110 Liter Pump = 175 LB/HR X .9 = 157 LB/HR, Safe for 315 naturally aspirated Horsepower
155 Liter Pump = 246 LB/HR X .9 = 221 LB/HR, Safe for 440 naturally aspirated Horsepower
190 Liter Pump = 302 LB/HR X .9 = 271 LB/HR, Safe for 540 naturally aspirated Horsepower
255 Liter Pump = 405 LB/HR X .9 = 364 LB/HR, Safe for 700 naturally aspirated Horsepower

Note: For forced induction engines, the above power levels will be reduced because as the pressure required by the pump increases, the flow decreases. In order to do proper fuel pump sizing, a fuel pump map is required, which shows flow rate versus delivery pressure.

That is, a 255 liter per hour pump at 40 PSI may only supply 200 liters per hour at 58 PSI (40 PSI plus 18 lbs of boost). Additionally, if you use a fuel line that is not large enough, this can result in decreased fuel volume due to the pressure drop across the fuel feed line: 255 LPH at the pump may only result in 225 LPH at the fuel rail.
 
Going with the 190lph isn't going to hurt anything...and if you do end up doing mods in the future, you aren't going to have to wonder whether or not you pump is up to the task. The difference in price between a 155lph pum and a 190lph pump is all of about $15. The return fuel system on our cars will recirculate whatever isn't needed back into the tank anyway. Go with a Walbro pump. They're the standard accross the board.
 
thanks jrichker. i dont understand why a reputable shop would tell i need at least a 190lph pump to make around 300 hp. what manufacturer do you recommend for a fuel pump ?

I can tell you with 100% certainty that a 155lph pump support over 400rwhp when the engine is NA.

Just buy a walbro, they make almost all the pumps anyway.
Difference is that you won't have to pay a brand name markup.

A 190lph pump has little use, it's more than you need on a NA combo, and less than you need a for a h/c/i with supercharger setup.
 
Going with the 190lph isn't going to hurt anything...and if you do end up doing mods in the future, you aren't going to have to wonder whether or not you pump is up to the task. The difference in price between a 155lph pum and a 190lph pump is all of about $15. The return fuel system on our cars will recirculate whatever isn't needed back into the tank anyway. Go with a Walbro pump. They're the standard accross the board.

Did you ever consider that the excess circulating fuel picks up heat? If it gets hot enough, it will boil in the tank and turn to vapor. Many Mustang owners have mistakenly removed or disabled the Evaporative Emissions carbon canister & associated plumbing thinking it would increase HP. Combine the excessive heat, vapor and lack of functional Evaporative Emissions control and you have a car that stinks like gasoline and loses a few MPG too. Considering the cost of gas and the annoyance of stinking like gasoline, I would recommend to use the size fuel pump that is consistent with the HP projections of the engine.
 
Did you ever consider that the excess circulating fuel picks up heat? If it gets hot enough, it will boil in the tank and turn to vapor. Many Mustang owners have mistakenly removed or disabled the Evaporative Emissions carbon canister & associated plumbing thinking it would increase HP. Combine the excessive heat, vapor and lack of functional Evaporative Emissions control and you have a car that stinks like gasoline and loses a few MPG too. Considering the cost of gas and the annoyance of stinking like gasoline, I would recommend to use the size fuel pump that is consistent with the HP projections of the engine.

Considered it....sure, but only for a few seconds until I thought logically about it. I have yet to see it proven in a large scale automotive fashion. Gasoline boils anywhere from 100-400F depending on the aditives. I've seen fuel sit in a container in the direct sunlight all day long and hardly get above ambient. I find it hard to believe that a small, pump circulating 10-gallons of cool fuel for hours on end is going to cause any boiling of any sort. The heat bleeds off as quickly as it's made for the most part. I've seen in happen in small scale applications like an ATV, but you're only working with a couple of gallons of fuel, located in a tank that sits right on top of the engine.

Lots of guys out there running 255lph pumps and even some inline pumps on top of that on their daily drivers that aren't having any issue. I was one of them. Drove my Supercharged Cougar for 6-years (befor I sold it) with bth a 255lph Walbro and Kenne Bell Boost-a-pump without a single issue. And it spent most of its life below 2,000RPM.