diy regulated return

[machinestheman]

Originally Posted by Codum

Raising the fuel pressure to 100 psi vs. 50 psi? The injector mutiplies the high pressure oil pressure by 7, so at WOT when oil pressure is at lest say 3,000 psi then the oil in the injector is at 21,000 psi, the 21,000 psi oil pressure is transferred mechanically to pressurize the fuel that is stored in the injector and forced out the tip at the same pressure of the oil. The injector does not multiply the fuel pressure of the fuel in the injector. Now the question is can raising the fuel pressure provide benefits, only if the increased fuel pressure forces more fuel into the injector to be used during the injection cycle described above. The only way to get more fuel in the injector is to compress it. This can only be done if the fuel has air in it, I think we all know it does, so yes raising fuel pressure will force more fuel into the injector. How much? Not enough to make a difference in my opinion, but I have not tried it, just don't see it.

I am no expert, just trying to put it all together and explain it to where it's easier to understand.

this is a much better explanation however when the oil pressure starts at 3000 psi that's it, the oil pressure does not multiply. The fuel pressure multiplies or to clarify the injection pressure of the fuel multiplies the oil pressure going into the injector applied to a surface 7 times larger than the surface that is applying the force to the fuel will multiply the force by seven ie take a single bit axe drop it on your foot with the blunt end same amount of force applied to a large surface applies a certain amount of force, now drop the same axe on your foot with the sharp end applies the same amount of force to a considerably smaller area will increase the effort or in this case actually cause injury god forbid if the analogy does not make sence but at the end of the day "pounds per square inch" if the amount of pounds stays constant and the amount of inches decreases you have less inches to divide the amount of pounds of force 3000 pounds of pressure applied to 7 square inches (3000 divided by 7) vs 3000 pounds applied to 1 inch (3000 divided by 1) which will have more effort

[RatherBNtheWoods]

I'm not sure if that post is an argument for or against the OP.

But if the above post says that by physical dimensions(the top is 7 times larger than the bottom), the injector piston multiplies HPOP pressure(say 3000 psi) up to 21,000PSI(7 times 3000), and that fuel pressure is not a factor in the mathematics what-so-ever,
then yes... I agree.

[jesilvas]

Originally Posted by RatherBNtheWoods

I'm not sure if that post is an argument for or against the OP.

But if the above post says that by physical dimensions(the top is 7 times larger than the bottom), the injector piston multiplies HPOP pressure(say 3000 psi) up to 21,000PSI(7 times 3000), and that fuel pressure is not a factor in the mathematics what-so-ever,
then yes... I agree.

Hpop pressure stays what it is once out of the hpop.
The fuel is what gets multiplied.

I made my Samsung SGH-I997 send this.

[Codum]

Ok, i found this explanation on line and i think we are all saying the same thing just differant ways of explaning it. "The computer controls how long the injector solenoid is energized (pulse-width, or time on in milliseconds), but it also determines the pressure of the fuel being injected by controlling the pressure of the oil (IPR duty-cycle, or the percentage of time on vs. off--AKA dwell) in the cylinder heads. The computer determines this based on engine load and driver demand by monitoring various sensors. Since the cavity at the top of the intensifier piston is seven times the size of the fuel cavity at the bottom, fuel is injected at a pressure seven times that of the computer-controlled oil pressure--oil pressure 3000 psi = injected fuel pressure 21000 psi. Due to the high oil system pressures, the spring which closes the poppet valve once the injector solenoid is deactivated has to be very strong--and because of this, the solenoid needs to be 110 volts. Once the poppet valve is closed, spring pressure returns the injector to its normal state and the oil is exhausted into the valve cover area to return to the sump." (Blackclouddiesel.com)

Bottom line 21,000 psi is the maximum pressure the fuel is injected, it is a direct result of the maximum oil pressure of 3,000 psi. (3,000 x 7,000 = 21,000). Increasing fuel pressure will do nothing other than cause premature wear on the fuel system.

[jesilvas]

Originally Posted by Codum

Ok, i found this explanation on line and i think we are all saying the same thing just differant ways of explaning it. "The computer controls how long the injector solenoid is energized (pulse-width, or time on in milliseconds), but it also determines the pressure of the fuel being injected by controlling the pressure of the oil (IPR duty-cycle, or the percentage of time on vs. off--AKA dwell) in the cylinder heads. The computer determines this based on engine load and driver demand by monitoring various sensors. Since the cavity at the top of the intensifier piston is seven times the size of the fuel cavity at the bottom, fuel is injected at a pressure seven times that of the computer-controlled oil pressure--oil pressure 3000 psi = injected fuel pressure 21000 psi. Due to the high oil system pressures, the spring which closes the poppet valve once the injector solenoid is deactivated has to be very strong--and because of this, the solenoid needs to be 110 volts. Once the poppet valve is closed, spring pressure returns the injector to its normal state and the oil is exhausted into the valve cover area to return to the sump." (Blackclouddiesel.com)

Bottom line 21,000 psi is the maximum pressure the fuel is injected, it is a direct result of the maximum oil pressure of 3,000 psi. (3,000 x 7,000 = 21,000). Increasing fuel pressure will do nothing other than cause premature wear on the fuel system.

3000 x 7000 isn't 21000 :
And that is based on using max ICP. At those high pressures, going from 55 to 105 is such a negligible amount, no one really takes it into account. It technically will yield higher hpf injection, but that's splitting atoms

I made my Samsung SGH-I997 send this.

[RatherBNtheWoods]

Originally Posted by jesilvas

3000 x 7000 isn't 21000 :
And that is based on using max ICP. At those high pressures, going from 55 to 105 is such a negligible amount, no one really takes it into account. It technically will yield higher hpf injection, but that's splitting atoms

I made my Samsung SGH-I997 send this.

I think he meant 3,000 x 7 = 21,000


jesilvas,
The HPOP doesn't put out 3,000PSI all the time. 3,000 is the maximum. HPOP out is variable from something like 650 up to 3,000. The ECM doesn't operate the injectors(spool valve) until around 550PSI. From there, depending on total fuel required for demand and RPM, the ECM varies ICP( pressure from the HPOP) and the amount of time between the open 48v pulse and the close 48v pulse being applied to the respective coils that move the spool valve to and fro.

[dentexpowerstroke]

^ I think you're starting to talk about 6.0 stuff now. 7.3s use a little more than just 48v

[RatherBNtheWoods]

Sorry, make that 110v or 120v for a 7.3, 48 -58v for a 6.oh

[jesilvas]

Originally Posted by RatherBNtheWoods

I think he meant 3,000 x 7 = 21,000


jesilvas,
The HPOP doesn't put out 3,000PSI all the time. 3,000 is the maximum. HPOP out is variable from something like 650 up to 3,000. The ECM doesn't operate the injectors(spool valve) until around 550PSI. From there, depending on total fuel required for demand and RPM, the ECM varies ICP( pressure from the HPOP) and the amount of time between the open 48v pulse and the close 48v pulse being applied to the respective coils that move the spool valve to and fro.

You said what I just said.
I poked, then stated that was max icp

I made my Samsung SGH-I997 send this.

[machinestheman]

well now that thats all hammered out and their seems to be a solid consensus hope this helps the op out i am sure that all involved were not intending to hijack this thread but i know i personnaly didnt want to read your next thread about your fuel system failure of some sort given what has been discussed i think it can be simply capped by stating

the fuel pressure feeding the injector only plays a factor if theirs air in your fuel so a good quality filter/ regulated return system should safely reap the same benifits of 115 psi of fuel except that your fuel pump will live much longer to tell the story four pages later i hope you have achieved something from our bickering