Fuel Pump and MAF questions

I have a similar set up. I would get the Cobra X3Z ECU and Cobra MAF and throttle body It is already been set by Ford for the 24lb er's . You cant beat Ford factory engineering

I ran with stock fuel pump for maybe 50 miles on the new setup. I had alot of issues with tuning and pinging. So I upgraded the pump to a 190lph unit and it was like night and day. Runs like a scalded cat now.

90topdown said:

I have a similar set up. I would get the Cobra X3Z ECU and Cobra MAF and throttle body It is already been set by Ford for the 24lb er's . You cant beat Ford factory engineering

I ran with stock fuel pump for maybe 50 miles on the new setup. I had alot of issues with tuning and pinging. So I upgraded the pump to a 190lph unit and it was like night and day. Runs like a scalded cat now.

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How does that work? i have a 93 GT that im going to bolt up a KB supercharger on that would be nice to have the 24# inj... MAF....and TB does that really work what ill effects does it have on the other components in the car....? does it change timing and stuff like that?

Fuel pump

The stock pump and C&L meter worked fine for me before the SC was installed.

MY 85 GT said:

How does that work? i have a 93 GT that im going to bolt up a KB supercharger on that would be nice to have the 24# inj... MAF....and TB does that really work what ill effects does it have on the other components in the car....? does it change timing and stuff like that?

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If you are going blown, you really need to think out your air/fuel delivery combination.

You do not want to run a blown motor lean. Make sure that your air/fuel ratio is good and you have a safe tune.

Injector sizing will depend on amt of HP you will be making. How much HP are you planning? What is the rest of your engine combo?

As far as the fuel pump goes, I would just put in a 255 lph and be done with it. The fuel recirculates anyway so don't worry about oversizing it.

I went with a 190lph on mine as I have no plans for any future power adders.

255 pump. buy it once and only once. Leaves room for a n/a 408 even.

Buy a C&L for now calibrated for 24's. U really don't need the 24's with just irons and cobra intake. the 19s should work. No need on buying injectors if ur just going to have to buy bigger ones for the 408.

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”


Here's a chart for those of us too lazy to do the math or don't have a calculator handy...

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.

No way would I install a 155 in this situation.
The difference in price between a 155, a 190, and a 255 is not that much, less than buying a 155 and then a 255!

I'm not buying the 255 now, my plans change to much, and i might not have this car next year. I was planning on going with a 155, as i can find them at a decent price, but only if i need it. I have had enough knowledgeable people state i "might go lean" that i will just get the aftermarket pump.

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buy the right parts the first time. Price between 155 and a 255 isn't much.