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Old 11-28-2010, 10:08 AM
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Default Dodge Cummins Injector Information

Injectors for the Dodge Cummins from 89-02' all work the same. The 24V's have a different top part on the injector but they are still the same. The difference comes with pop pressures and orifice size on the injector tip.

Injectors work by "popping" when the fuel pressure reaches the pop off point. This is caused by a pintle that pushes against a spring using the fuel pressure and unseats itself. When that happens, the injector injects fuel at high pressure, atomizing it. When the pressure drops, the injector seals off and waits for more pressure then pops again. This action happens very quickly and the injector pops several times per injection cycle. How much fuel is pushed through the injection line determines how many times the injector pops off. When the pump stops pushing fuel, the excess pressure in the injector is relieved into the return line to be returned to the fuel tank or fuel filter.

The injection lines act like a mini storage tank because they expand when the pressure spikes. The line aids in smoothing the spike and providing a longer duration injection. Bigger injection lines will increase the duration since they have more surface area to expand, therefore more to contract. All of the injection lines are the same length because of this. If one line was longer than the other, the the longer line would inject more fuel creating more power in that cylinder. To have a smooth engine they all are the same length, though it would have to be pretty different lengths to make any difference, but you get the idea.

The orifice size in the injector nozzles help to determine the amount of fuel injected. Obviously a bigger hole means more flow, which is exactly how the injectors are set up. You can get bigger holes or more holes to increase flow and gain power. This is how aftermarket injectors increase power.

The copper washer on the bottom of the injector is crucial to proper operation. When the injector injects fuel, it injects it in a cone shape that should be going directly into the bowl of the piston. If the copper washer is the wrong size, it can set the injector too high or too low causing the fuel to hit the outer edge of the piston or the inner part of the bowl, causing inefficient operation.
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1997-12V-NV4500-Dana 80/3.54/2wd-350k---21-27mpg
Removed AFC--No Plate--13.5* timing--BHAF--5" Exhaust--Valair Clutch
1994-Jeep Cherokee-5spd-3.07-4wd-202k---16-19mpg

Last edited by stodg73; 09-16-2012 at 10:50 AM.
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Old 12-25-2010, 12:30 AM
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Interesting! I appreciate the info! Im looking at bigger injectors for mine
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'02 "Carrie" 4x4 Auto, 6in straight pipe TBE, Autometer Gauges, AFe Stage II CAI w/ Torque Tube, ATS Intake Manifold, ATS Aurora 3k, AirDog150, Smarty, Edge Comp "HOT", BD Stealth Cover, ATS DYNO on 8/6/2011 = 447hp 970ft-lbs
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Old 12-25-2010, 08:11 AM
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A guy on the other forum I am on found this. Pretty golden info. http://www.competitiondiesel.com/for...ad.php?t=88662
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1997-12V-NV4500-Dana 80/3.54/2wd-350k---21-27mpg
Removed AFC--No Plate--13.5* timing--BHAF--5" Exhaust--Valair Clutch
1994-Jeep Cherokee-5spd-3.07-4wd-202k---16-19mpg
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