Delta VS
Supporting Vendor
It’s time to start talking about our 80 Series “common rail” Cummins conversion project so interested folks can sign up for a test drive, to be given on the first day of Cruise Moab this year (2025) (email info @ deltavs . com for details).
We have been working on a “common rail” Cummins conversion kit for a while now. There is still work to do, but the first rig has over 500 miles on it (’94, build thread starts focusing on common rail here: https://forum.ih8mud.com/threads/recently-acquired-locked-94-build.1114432/post-15366265). The second rig (’97) is up next (build thread starts discussing common rail here: Builds - Dirty Koala Build - Cummins Common Rail + NV4500 + HF2AV Swap - https://forum.ih8mud.com/threads/dirty-koala-build-cummins-common-rail-nv4500-hf2av-swap.804271/post-15455920). Once both are finalized, we will be taking orders for DIY kits, and doing installs in our shop.
The Why:
We chose this particular engine conversion because we have used it to achieve world records, own them, and know them. We wanted the option to put the best engine in the best vehicle, and because Cummins, duh.
Some of the criteria:
Brief overview of Cummins for those who feel like some learnin’:
There are a handful of Dodge pickup versions of the Cummins engine with most of the differences appearing in the fuel system, detailed below.
Let's start with the basic components of a diesel engine fuel system, in order of fuel travel path:
Quick breakdown of injection systems:
VE and VP pumps are both rotary pumps. Key factors of rotary pumps:
We have been working on a “common rail” Cummins conversion kit for a while now. There is still work to do, but the first rig has over 500 miles on it (’94, build thread starts focusing on common rail here: https://forum.ih8mud.com/threads/recently-acquired-locked-94-build.1114432/post-15366265). The second rig (’97) is up next (build thread starts discussing common rail here: Builds - Dirty Koala Build - Cummins Common Rail + NV4500 + HF2AV Swap - https://forum.ih8mud.com/threads/dirty-koala-build-cummins-common-rail-nv4500-hf2av-swap.804271/post-15455920). Once both are finalized, we will be taking orders for DIY kits, and doing installs in our shop.
The Why:
We chose this particular engine conversion because we have used it to achieve world records, own them, and know them. We wanted the option to put the best engine in the best vehicle, and because Cummins, duh.
Some of the criteria:
- Have a modern fuel system for a clean burning, highly efficient engine package
- For emissions sake, the 03-07 are the most forgiving (in the common rail family). No EGR, no DEF, NO WORRIES. Since this will be a kit, we needed to keep that in mind.
- Drivability and noise level are miles beyond the other options, with only a VE pump being able to get even halfway close to the pleasant driving experience of a common rail
- Highly tunable for many applications. Availability of onboard tune selection, can have a “mileage tune” for getting to the trail head then just switch to the “soft tune” to avoid breaking driveshafts, etc. Have a valet tune for the discerning gentleman, along with a “full power” tune for when that gentleman wants to roast all four tires and send diff bits into space. Five tune slots.
- Other benefits of the common rail blocks are:
- more o-ring seals instead of paper and rubber gaskets for less drips
- thread-in block heater instead of a weird leaky freeze plug replacement
- two turbo oil drains machined in for when you’re ready to do compound turbos
- stronger casting
- higher flowing head in stock form
- boost controlled by ECM when using a stock or stock-style turbo
Brief overview of Cummins for those who feel like some learnin’:
There are a handful of Dodge pickup versions of the Cummins engine with most of the differences appearing in the fuel system, detailed below.
Let's start with the basic components of a diesel engine fuel system, in order of fuel travel path:
- Lift pump- Generally a low-pressure fuel pump located in the tank in OEM applications. (8-45 psi depending on application)
- Injection pump- This is the heart of the system. It is essentially a precise hydraulic pump, controlling:
- Timing (at what point of the compression stroke does fuel start getting sent into the cylinder)
- Duration (the amount of time fuel is injected into the cylinder)
- Pressure (which determines the volume of fuel delivered, in conjunction with the duration) of the fuel delivery to the cylinder. Pressures range from 3,000 psi to over 30,000 psi (!!!) depending on the system.
- Injection lines- Fuel travels from the injection pump to the injectors via these tubes. For the lower pressure mechanical systems, it is vitally important for these lines to be equal length so timing is not affected.
- Injectors- For a mechanical system, these are basically “pop-off” valves with a stiff spring that is overcome by the pressure wave sent through the injection line by the injection pump. The pressure at the injector inlet will “go to zero” between injection events, rapidly fluctuating between zero and 3,000 psi from one event to the next. Max injection pressure does not change in this type of system. In electronic systems, injectors are controlled by a solenoid. For a common rail system, you can think of the injectors as computer-controlled hydraulic valves where the pressure stays constant at the inlet of the injector, only changing inside the actual injector tip, during the injection events. Max injection pressure is constantly variable, from about 4,500 psi at idle to upwards of 32,000 psi under load.
- 89-93 has the full mechanical, rotary VE injection pump and “12 valve” head (2 valves per cylinder) ~160hp in stock form. This is the same injection tech as the Toyota 1HDT-FT engine.
- 94-98 has the full mechanical, inline P7100 injection pump and “12 valve” head- 180-215hp in stock form
- 99-02 has the half mechanical, half electronic rotary VP44 injection pump and “24 valve” head (all heads are 24 valve from 99 onward, 4 valves per cylinder). Approx 235-245hp in stock form. This is the same injection tech as the Toyota 1HDT-FTE engine.
- 03-07 switches to the “common rail” injection system, which is when the engines “got quiet” ~235-370hp in stock form. This common rail system utilizes an incredibly simple, three-stage, “pressure only” CP3 injection pump.
- 08-12 slight bump in displacement, adds EGR, same common rail injection system
- 13-18 adds DEF, same common rail injection system
- 19-24 we don’t talk about these (switches to sintered metal block and adds roller cam, both of which fail consistently. Slightly different, but basically same common rail injection system)
Quick breakdown of injection systems:
VE and VP pumps are both rotary pumps. Key factors of rotary pumps:
- These are much more compact units
- A single piston compresses the fuel for all six cylinders by rotating on a swash plate, this controls timing, duration, and pressure all at once
- The internal components (with tolerances measured in microns) are lubricated by the fuel, making it much more sensitive to fuel impurities
- Somewhat variable timing (within a window), typically controlled by internal fuel pressure (VE pump) or electronically (VP pump)
- Injection pressure on the order of 3600ish PSI (VE pump) 4200ish PSI (VP pump)
- Generally nice drivability for a mechanical pump
- Internal components are lubricated by crankcase oil, much more robust and ain’t care about fuel impurities, or even fuel, really
- Gigantic. It’s said to require approximately 70hp to spin it at 3000 rpm. About half the length of the block.
- Runs static timing. Inline pumps are usually (not always, but quite typically) on more industrial applications that run at idle or a single elevated rpm. This factor is what people associate with the “loud” diesel effect. When running static timing, you set it to run well at cruising rpm, in the 1800-2100 rpm range. This means at idle, you will have extremely advanced timing, leading to the rattly as hell sound people think of when you mention Cummins.
- Injection pressures around 3700 PSI
- Compresses fuel with an actual camshaft. One piston per engine cylinder compresses fuel.
- Able to inject a massive quantity of fuel, fairly quickly, due to individual fuel pistons for each engine cylinder. For this reason, and the durability of crankcase oil lube, these pumps are often defaulted to as “the best”, when in reality the ability to make lots (like 1500hp/2500tq) of power comes at the expense of drivability, smoke/haze, and cold start ability.
- Starts the process of moving to an electronic injection system, first engine to have a programmable ECM for software control of timing and fuel delivery quantity
- Still a rotary pump, but the timing and fuel delivery are controlled by electronic solenoids inside the pump moving the control levers/linkages versus the governor weights of the VE pump
- Poor design using fuel to cool the internal electronics, if feed fuel pressure is lost (from in-tank pump for instance), solder joints inside melt from overheating, and injection pump is no longer good, leading to an expensive repair. This is a VP44-specific issue; we have not heard about it with other pumps.
- First system to completely separate timing, duration, and pressure from engine speed, as well as completely controlling each parameter individually via software only
- Uses a CP3 injection pump that easily produces 32,000 psi. These are exceedingly basic, three-stage pumps with one job, making gobs of pressure.
- Instead of fuel being compressed in the pump for each firing of an injector and sent down the injection line to a break over spring, the CP3 compresses fuel all the time and sends it to a fuel manifold, a “common rail”, that acts as a hydraulic accumulator. Injector lines go from this rail to the injector in the shortest path.
- Fuel pressure at the injector inlet is constant, and a solenoid in the injector receives a signal from the ECM and opens/closes based on the software demands.
- Injectors are more complex with smaller passages due to the order of magnitude increase in pressure they see, leading to more sensitivity to fuel impurities
- Due to the exceedingly high pressures and short distance the metered fuel has to travel (NOT through a long, equal-length fuel line), injection events get extremely short, to the point where fuel can be injected multiple times per stroke of the piston. This allows the creation of a “softer” flame front hitting the piston, exactly perfect timing for every single RPM, much better fuel atomization, etc. All of these add up to the engine making much less noise under normal operating conditions.
- Higher pressures and near complete control of injection events lead to much higher efficiency, extracting more power from the same amount of fuel while burning much cleaner
- Both are 4 stroke engines - “suck, squish, bang, blow” (intake, compression, combustion, exhaust) - no difference there
- The difference lies in when the fuel is introduced to the 4-stroke combustion cycle
- Gas engine sucks in an air/fuel mixture on the intake stroke, compresses that combustible mixture (giving the opportunity for pre-ignition/detonation), near top of compression stroke, spark plug ignites said mixture and that resulting explosion pushes the piston down during the combustion stroke, then all the burned stuff is pushed out on exhaust stroke
- Diesel engine sucks in dry air on the intake stroke, compresses that dry air (eliminating the possibility of pre-ignition/detonation, allowing insane compression ratios and boost levels) then the injector injects fuel near the top of the compression stroke when the dry air in the cylinder is exceedingly hot, this fuel spontaneously ignites due to said hotness, at this point (combustion/exhaust strokes) it’s essentially the same as a gas engine
- Tuning a mechanical pump is similar in process to tuning a carb; turn some screws, slide some things, rotate some things, viola, +250hp. Ok, so maybe not like a carb…
- Tuning an electronic pump (VP44 or common rail) is the same process as tuning an LS, you use a laptop.
- Installing different hardware (larger injectors, higher flowing pumps, etc) usually goes along with any of the tuning above.
- Generally speaking, it’s a fairly easy task to hit the following numbers with stock hardware:
- From 89-93: 250hp
- From 1994-02: 375hp
- From 2003 on, close to 500hp is a few button clicks away
- Starting in 2006, software called EFILive can be used to reprogram the ECM. Along with this, you gain the ability to have a 5-position switch to shift between tunes “on-the-fly”/under load.
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My truck is pretty-much a DeltaVS parts billboard. 
otherwise I might have considered driving to Utah. 
