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  #1  
Old March 23rd, 2012, 10:09 PM
cdb
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Clark Bowen
1969 Series 2a/OM617 Bugeye 88"
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fuel flow

I replaced the standard (21lbs according to FiveOMotorsports) fuel injectors with 24lb Bosch injectors in my 4.0 motor with the Lucas 14cux because I wanted increased fuel flow with the supercharger, but I may have actually decreased the flow.
The stock fuel pump delivery pressure, per the manual, is 2.4-2.6 bar (34 to 37lbs), but the Bosch injectors I bought from www.fiveomotorsports.com flow 24lbs at 3 bar (43.5lbs).
So, unless there was an adjustable or rising rate fuel regulator added with the supercharger (it's behind the supercharger and I can't see it) it would seem I'm only getting about about 20.41 lbs ((37/43.5)X24).
Am I thinking this through correctly?
Is the delivery pressure: 1. The maximum pressure from the pump or
2. The pressure after the stock fuel regulator?
I will check my fuel flow when I finish wiring up the MegaSquirt, but I wanted to see if my thinking was correct for now.
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  #2  
Old March 24th, 2012, 02:15 AM
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Dan Berry
1995 D90
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Highest delivery pressure is set by the regulator, until the pump can't keep up. Believe I saw at least 70psi when I checked direct to my pump.

If needed you can buy a adjustable regulator from summit racing or similar. An old racing trick is to put the stock regulator in a vice and slightly "crush it". This would usually give an increase of 4 or 5.
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  #3  
Old March 24th, 2012, 09:44 AM
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Bill Adams
66 109 sw 94 lwb
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A gallon of gas is about 6 pounds. The difference, in a performance framework, between pumping 3.5 and 4 gallons per hour thru an injector (multiplied by 8 or a possible 28 or 36 gallons per hour respectively) is about nil.
Dunno. Maybe you only get to drive your truck half an hour between fill ups. What I'm say'n is that even with the 21lb injectors, you aren't going to "run out of gas".

My two cents:
I suggest that you lose the supercharger, get a fatter cam, buy the MS daughtercard so you have timing and spark (and a bunch of other control options) headers and a tunable FPR. That should be good for at least another 20 hp. Probably more, without the supercharger hassles.
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  #4  
Old March 24th, 2012, 04:04 PM
cdb
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Clark Bowen
1969 Series 2a/OM617 Bugeye 88"
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Join Date: Jun 2006
Location: Oregon, USA
Posts: 775
"My two cents:
I suggest that you lose the supercharger, get a fatter cam, buy the MS daughtercard so you have timing and spark (and a bunch of other control options) headers and a tunable FPR. That should be good for at least another 20 hp. Probably more, without the supercharger hassles."

Bill....
20 hp....patooey. I want power!
So, what hassles with the blower besides heat and knock?
Seems that the biggest hassle will be populating the VE tables and then adjusting the ignition. Going to a dyno tuner for that after I get it running.
I have the MS 2 Extra with timing and spark wired in, but I'll try to start it with the stock/MSD ignition first. The Ford EDIS is wired up and ready to replace the stock later.
Had the exhaust manifolds ceramic coated to reduce heat and wasn't convinced headers would improve the performance anyway.
Crower Cam installed has 258 degrees duration and .430 lift for intake and 260 degrees duration and .445 lift on exhaust. Is that fat enough?
With an adjustable FPR I could raise the pressure to 43.5lbs and then I'd know the actual flow through my injectors (24lbs). Then I could enter the correct data into the MS programming. Sound right?
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