73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Diesel Engine Discussion => Engine/Drivetrain => Cummins Swaps => Topic started by: big_al273 on March 26, 2016, 04:17:03 PM
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The after market fuel system guys I've talked too have said that their aftermarket universal fuel pumps can be run with either gasoline or diesel fuel with no issues, my question is if the same can be said of the AC/Delco EP381, my plan is (if doable) too have EP381 fuel pump(s) feeding a regulator on the fire wall for my Cummins conversion to keep a mostly stock fuel system up till the engine bay. has anyone run this or another AC/Delco "gasoline" fuel pump with diesel?
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bump.
Ideas and thoughts welcome.
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dont know why i didnt catch this but in my 91 v3500 i had the 350 in it i pulled the 350 and placed in a 12v. i didnt touch anything, no regulator needed. i did put in a fuel pressure gauge the ve pump the pressure has to stay below 15. and the system operates about 12 psi, its a little close and sometimes i hit 15 psi but i havnt had a problem and i have over 5k miles on my swap
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so your still running the EP386 from the TBI system? dual tank or single? what in all did you do to the fuel system, just bent the lines in the engine compartment? is there a "sock" on the fuel pump?
I will need to run the bigger pump and a regulator as i am aiming for 350-400 horse out of my to-be-built P-pumped 24valve, might have a engine to go look at in the next 2 weeks or so
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whatever is stock is what im running didnt touch it. didnt even mess with the fuel lines (dual tanks) put some fuel hose on the steel line and ran it up the fire wall then to the diver side into the fuel pump. even kept the oil pressure sensor and wires so the pump is only on if theres oil pressure. im going to move this post to the cummins swap section and notify william about it. he'll be able to tell you what you need
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With a ppump you need 18-22psi at idle and 10 psi rise for every 1000rpm increase, I would strongly suggest switching to an aftermarket lift pump or gutting the intank and running the block lift pump. They are good to upwards of 400hp.
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i've found a lot of conflicting information on how much pressure to feed the P7100 from no more than 15 psi too never under 50 psi, and various reasons from underfeeding the injection pump causing overheating and lack of lubrication or over feeding causing cavitation in the injection pump so i will be doing more research but with my intention of keeping the dual tanks i am not willing to buy two FASS (or equivalent) systems, so a "stock style" fuel system would be ideal for my build. The goal for me here is to build the OEM Cummins Chevy that never was. As for the block mounted mechanical lift pump, they are very inefficient and the more rpms you run the worse they get, plus the 24 valve crank does not have the lobe to run it
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the ve pump you cant go over 15. but even in stock form i wouldnt doubt what will says
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is Bajaburban Will?
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lol yeah sorry
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https://www.facebook.com/syndicatechopshop/?fref=ts <<<<<<<<<<his shop
https://www.facebook.com/groups/1539000989649051/<<<<<<<<<Square body cummins swap
you will find more creditable info when it comes from him. other on his page can and will help but if will says something i would bet my last dollar on it to be true
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With a ppump you need 18-22psi at idle and 10 psi rise for every 1000rpm increase, I would strongly suggest switching to an aftermarket lift pump or gutting the intank and running the block lift pump. They are good to upwards of 400hp.
clarify this statement for me, are you saying you need to somehow increase the pressure with the rpms? or are you saying to base your input pressure on how many rpms you will be running?
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The pump needs more pressure at high rpm than low rpm to feed the pistons during the injection cycle, so as the rpm rises you need more fuel, thats why the lift pump is crucial when designing a fuel system. at idle the pump only needs 18/22 psi but at 2200 it needs 32psi, otherwise you will starve your pump.
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the P7100 needs more fuel supply than a ve, the lift pump actually helps feed the piston in the ppump, the ve and vp44 both have internal pumps that will pull fuel in the event of a lift pump failure but they are weak at best. some 24v cams do infact have the lift pump lobe. the block mounted lift pump is good for about 500hp. the reason so many people go to an electric lift pump is the flow is stable and the pressure can be adjusted to feed correctly.
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Ok another question, is there any issue with having 30-40 psi of fuel at idle? what about 60 psi of fuel at idle? the P7100 injection pump has a fuel return, correct?
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the P7100 needs more fuel supply than a ve, the lift pump actually helps feed the piston in the ppump, the ve and vp44 both have internal pumps that will pull fuel in the event of a lift pump failure but they are weak at best. some 24v cams do infact have the lift pump lobe. the block mounted lift pump is good for about 500hp. the reason so many people go to an electric lift pump is the flow is stable and the pressure can be adjusted to feed correctly.
Ok another question, is there any issue with having 30-40 psi of fuel at idle? what about 60 psi of fuel at idle? the P7100 injection pump has a fuel return, correct?
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Anyone have anything on this subject since Bajaburban can't be bothered?
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did you pm him? or check out his facebook under his profile?