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[TTC]

it is my understanding that in order to get this you must subtract Manifold pressure efrom fuel pressure.  I sort of understand how it works, the intake manifold has X amount of PSI which decreases the fuel pressure in the manifold as opposed to that at the rail.  How is this information a useful tuning tool?  I'm just looking for a better explanation.

[stealthiskey]

If you have a working FPR your differential pressure should always stay around 42 psi, or whatever you have it set at.  Obvi more fuel pressure (differential pressure) puts in more fuel.

[Tim]

its the pressure across the injector.

If your injector was spraying into open air atmosphere then the fuel pressure would be the only thing pushing fuel through an open injector.

If your injector is spraying into a turbo pressurized manifold the pressure in the mani is pushing back against the fuel rail pressure.  So across the injector is the rail pressure minus the mani pressure. so you will get less fuel for the same pulse width and fuel pressure than an injector spraying into open atmosphere.

If your injector is spraying into an intake under vacuum then the vacuum is pulling the fuel as well as the rail pressure pushing it.  So across the injector is the vacuum plus the rail pressure.  You will get more fuel for the same pulse width and fuel pressure than an injector spraying into open atmosphere.

Knowing if your differential fuel pressure is constant or increasing etc. in relation to your mani pressure lets you know how your injectors are going to react to differnt pulse width changes etc.

I hope that helped not re-explain the part you already understood

[Joseph Davis]

its the pressure across the injector.

Which dictates how much flow you have across the injector, regardless of NA or boosted or sprayed on.

[TTC]

Thx all, was basically looking for confirmation.

[Joseph Davis]

What are antihlepers?

[TTC]

Helping with a hint of condescension and arrogance.  Kinda like telling someone to fuck off but making them happy to be on there way.

[Joseph Davis]

Cool, now the other question is why the Dodge van avatar repping a Toyota site?

[Robb]

Cool, now the other question is why the Dodge van avatar repping a Toyota site?

Also, throwing the nekkid chick out the van means you cant go back and hit it again.  Not cool.

[TTC]

Stole it from bangbus, thought it was funny?