The Last HPOP Your 7.3L Will Ever Need

It’s no secret that chasing horsepower with a 7.3L Power Stroke calls for big injectors, and thanks to modern aftermarket HEUI injector technology substantial gains can be had without breaking the bank. However, every factory injection system has its limits—and the 7.3L’s is no different. Once you venture beyond the 550-rwhp range (or, as a general rule of thumb, go larger than a 250cc injector), you run the risk of the stock high-pressure oil pump not being able to keep up. And if you’re unable to maintain high-pressure oil volume being delivered to the injectors, you’ll never realize the full potential of a big set of sticks. To remedy this situation and fully enjoy your truck, you’ll either need to add a higher volume HPOP or run dual pumps.

In recent years, 300cc or larger injectors equipped with 200-percent over nozzles have proven capable of supporting 650-rwhp or more and provide great streetability with proper custom tuning, but (as stated) they require a larger displacement high-pressure oil pump or dual HPOP’s to support them. With a set of 350cc injectors fitted with 200-percent nozzles on the way, ’97 F-250 owner, Hastings Foote, readied his highly modified 7.3L’s injection system for the increased high-pressure oil demand that was to follow. His pump of choice was the time-tested Gen3 unit from Swamps Diesel Performance. Of all the big injector 7.3L Power Strokes we come across, nearly 50-percent of them are running this pump. For an HPOP that works in conjunction with the factory pump, installs in just two hours, and supports any size injector on the market, it’s no wonder the Gen3 is so common in the 7.3L world.

After being bitten by the performance bug (and with a 5.9L common-rail Dodge at his disposal for daily driving and towing duties), Hastings Foote decided to turn his ’97 F-250 into a play toy. Readying the 140,000-mile, stock bottom end 7.3L Power Stroke for more power called for ARP head studs, Irate Diesel Performance competition valve springs, and Smith Brothers chromoly pushrods. Then, with a set of 350/200 hybrid injectors on order, he knew it was time to step up to a higher volume high-pressure oil pump, hence the reason for this article.

In preparation for the big injectors, the engine was saddled with a complete T4 turbo mounting kit from Irate Diesel Performance and a BorgWarner S471. Equipped with a cast 71/100mm compressor wheel and the common 74/83mm turbine wheel, the S471 was also spec’d with a 1.10 A/R exhaust housing—the second largest available—for optimum high rpm flow (i.e. peak horsepower potential).

A steady, 65-70-psi diet of fuel supply makes it to the injectors thanks to a competition fuel system from Irate Diesel Performance. The compact, race-ready package incorporates a Fuelab Prodigy pump, -8 fuel line from the tank to the pump and the pump to the engine, and a regulated return system.

To keep fuel free of air and ensure each cylinder sees adequate supply pressure, an Irate Diesel Performance regulated return system is employed. The system consists of 304 stainless steel hard lines, Parker fittings, a Fuelab adjustable pressure regulator, and it also deletes the factory fuel bowl from the lifter valley.

Swamps Diesel’s Gen3 high-pressure oil pump assembly is made up of an industrial grade, Haldex hydraulic pump, a proprietary drive gear that works in conjunction with the factory pump’s drive gear, and a CNC-machined, billet-aluminum high-pressure oil reservoir. Each Gen3 unit is shipped 90-percent assembled and ready to install. Utilizing new mounting bolts, the Gen3 mounts directly above the factory location pump.

The Gen3’s gear pump draws its oil from the reservoir and feeds it to a port at the rear of the factory high-pressure oil pump, which is common to the pump outlets, both cylinder heads, and the injection pressure regulator (IPR) (also note that no second IPR is required). A check valve on the gear pump inlet prevents the factory pump from back-feeding through it when starting the engine.

With the Gen3’s billet-aluminum high-pressure oil reservoir replacing the factory reservoir completely, Swamps includes a fresh OEM gasket, new mounting hardware, and accommodates the factory oil pressure and oil temperature sending units. Finding fittings or bolts with their threads coated in paint means they’ve already been tightened or fully sealed prior to shipping (arrow).

The process of installing the Gen3 began with the removal of the mounting bolts for the factory high-pressure oil pump reservoir (arrows). Swamps supplies all new reservoir mounting bolts with its Gen3 pump.

Next, the inspection plug on the top of the factory high-pressure oil reservoir was removed (arrow) in order to suction out the oil. Note that if you opt to pull the reservoir without first extracting the oil you will have a slight mess on your hands, but nothing major.

With the oil suctioned out of the factory high-pressure oil reservoir, the oil pressure sensor was disconnected, along with the engine oil temperature sending unit being pulled from the back of the reservoir. From there, the stock reservoir was lifted off of the high-pressure oil pump.

Thanks to the Gen3 mounting above the factory location high-pressure oil pump, removing the stock high-pressure oil reservoir is as deep as you have to go during the install. Notice the badge on the existing pump: the reputable T500 from Terminator Engineering.

Because the Irate Diesel Performance regulated return fuel system on the engine was originally intended for a single high-pressure oil pump application, its stainless steel lines had to be reworked to clear the Gen3. In addition, the fuel pressure regulator was disconnected from one of the return lines and swiveled out of the way for more working space during the install.

A replacement (OEM) high-pressure oil reservoir gasket is included with each Gen3 pump, which works with all late ’96-’03 7.3L engines. On ’94.5 to early ’96 engines, the end user has to cut the supplied gasket to match the original one, and Swamps recommends sealing the rest of the reservoir’s mating surface area with RTV sealant.

The next step entailed removing the hex head plug at the rear, driver side top of the stock location high-pressure oil pump. It would be replaced with this 90-degree 6MB-8MJ fitting that came with the Gen3 pump. The fitting would eventually be connected to the hard line that hangs off of the back of the Gen3.

Prior to installing the Gen3, the small amount of left over oil that had drained into the lifter valley during the factory high-pressure oil reservoir removal was cleaned up. Setting the Gen3 in place on the front cover called for a helping set of hands to keep the hard lines for the regulated return system out of the way.

For ample clearance between the Gen3 reservoir and the serpentine belt, Swamps includes a new thermostat housing neck (shown). We were pleasantly surprised to discover that it wasn’t needed in our install, and we were able to leave the OEM neck undisturbed

While the supplied Gen3 mounting bolts were installed and fully tightened up as soon as the pump was in place, none of the fittings were snugged up until all of them were connected. The reconnecting of the regulated return fuel lines would be the last step in the Gen3 installation.

To ensure plenty of oil is on tap during periods of high demand, an auxiliary oil feed line is utilized on the Gen3 pump (arrow). Per Swamps’ instructions, the auxiliary oil line inlet was connected to the oil galley at the front of the driver’s side of the block by way of the supplied 4MP-6MJ fitting replacing the factory ¼-inch NPT plug. A braided stainless line (arrow) carries oil supply from the block to the Gen3.

A 90-degree fitting with a straight adapter installed in the Gen3’s high-pressure oil reservoir accommodates the factory oil pressure sending unit (shown). The EOT sensor ties into the provided tee that also connects to the auxiliary oil supply line at the rear of the reservoir.

With all fittings finger tight and the braided stainless oil supply hose positioned to our liking, all fittings were tightened up, and then double checked. Before firing up the engine, the high-pressure reservoir was refilled.

When reinstalling the fuel pressure regulator (again, which was part of the previously installed regulated return system), the regulator had to be repositioned with its gauge facing the hood. Otherwise, the 90-degree hard line connected to the bottom of the regulator wouldn’t have cleared the Gen3 reservoir.

Despite having the injection system opened up to atmosphere, the engine started with relative ease, idled great, and it only took a short test drive to purge all air from the system. For those wondering when the factory fuel bowl was ditched, it went by the wayside when the Irate competition fuel system and regulated return were installed. It’s also worth mentioning (and as you’ve probably noticed) that the Gen3 will not work in conjunction with the factory fuel bowl in place.

Given everything that’s done to the truck at this point (350/200’s, competition fuel system, S471, built E4OD, and now the Gen3), it should be good for 650-rwhp. And should Hastings ever decide to step up to a set of 400/400’s (or larger), he’ll have peace of mind knowing that the Gen3 will easily support their high-pressure oil needs.

SOURCES

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Irate Diesel Performance
503.435.9599
iratediesel.com

Swamps Diesel Performance
615.793.5573
swampsdiesel.com

FREQUENTLY ASKED QUESTIONS

What are the trade-offs between power, smoke, and cost in diesel truck modifications?

Understanding the Trade-offs in Diesel Truck Modifications

When modifying diesel trucks for enhanced performance, three critical factors often come into play: power, smoke, and cost. Balancing these elements is essential, and each choice comes with inherent trade-offs.

Power and Fuel Efficiency

Diesel engines thrive on fuel to generate power. Increasing the amount of fuel can significantly boost engine output, but there is an optimal point where efficiency peaks. Improved fuel atomization enhances power and reduces exhaust gas temperatures (EGTs), fostering a more efficient burn.

Smoke: The Inevitable Byproduct

When more fuel is added to the system, the turbocharger produces extra boost, which can increase power output. However, this also commonly results in excess smoke, especially under heavy acceleration. Smoke is not just aesthetic; it indicates incomplete combustion, which often occurs with the use of oversized injectors and turbochargers. As these components push for greater power, smoke may be evident, particularly at the start, though it may dissipate to a thin haze as the vehicle gains speed.

The Cost Factor

Achieving the perfect balance between power, smoke, and efficiency requires precision engineering, which can be costly. High-end solutions involve sophisticated tuning, superior air-fuel management, and top-tier components, all of which demand a significant financial investment. For most enthusiasts, such expenses are prohibitive.

Practical Compromises

For the average diesel truck owner looking to maximize performance without breaking the bank, strategic compromises are often necessary. This typically involves installing larger injectors and turbochargers, sometimes complemented by nitrous oxide for an additional power boost. While effective in increasing horsepower, these modifications usually result in noticeable smoke on acceleration, though it often lessens at higher speeds.

Conclusion

In sum, modifying a diesel truck requires careful consideration of trade-offs between power, smoke, and budget. While achieving a perfect balance necessitates expensive technology and components, practical adjustments can still deliver impressive results, albeit with some increase in emissions. Each modification decision should align with the owner’s priorities, whether it’s maximum power, minimal smoke, or keeping costs manageable.

Why do some trucks produce more black smoke and others less, despite having similar modifications?

Why Some Trucks Smoke More Than Others Despite Similar Mods

The phenomenon of trucks belching black smoke isn’t just about raw power—it’s about tuning, efficiency, and sometimes, trade-offs. Here’s why two similarly modified trucks might behave differently:

Fuel Overload vs. Atomization

Fuel Overload:Diesel engines run on fuel, and it’s a common misconception that more fuel automatically equates to more power. In reality, throwing excess fuel into the mix can lead to incomplete combustion, resulting in that signature black smoke.
Atomization Matters:Efficient atomization, or how well the fuel mixes with air, makes a big difference. Better atomization leads to more complete combustion, higher power, and reduced smoke.

Modifications and Tuning

Injector Size and Turbo:Large injectors and turbos are popular modifications. They can pump more fuel and air into the engine, which can produce more power but often results in more initial smoke if not finely tuned.
Balanced Tuning:Trucks that successfully balance fuel and air—aided by better tuning—can achieve high power with less smoke. After all, more fuel should build more boost, which typically means power with cleaner emissions.

Weight and Load Factors

Vehicle Weight:Comparing a heavy truck with a lighter one reveals differences. A heavier vehicle demands more effort to accelerate, often leading to more smoke if the engine is under-turbocharged for that weight.

Cost and Compromises

High-End Builds:Ultra-efficient, smoke-free diesel engines are possible but often expensive, involving top-tier components and meticulous tuning.
Standard Mods:For most enthusiasts, the goal is a balance—using practical modifications like big injectors or turbos and adding extras like nitrous. However, these can result in smoke during heavy acceleration, especially from a start.

Conclusion

In essence, black smoke is a sign of unburnt fuel, often stemming from oversized modifications that aren’t perfectly optimized. Meanwhile, trucks that produce less smoke have generally achieved a better balance of fuel, air, and tuning, though sometimes at a significantly higher cost. Understanding and adjusting these variables is key to finding the sweet spot between power and efficiency.

What factors should be considered when choosing a new HPOP for a Superduty truck?

Factors to Consider When Choosing a New HPOP for a Superduty Truck

Power Requirements

Determine the level of horsepower (HP) you want to achieve. Higher horsepower outputs require an HPOPthat can handle increased fuel demands, ensuring your engine runs efficiently without overheating.

Engine Compatibility

Ensure the HPOP is compatible with your truck’s specific engine model. Compatibility is crucial for optimal performance and to avoid potential mechanical issues.

Fuel Efficiency

A good HPOP should help in maintaining or improving your truck’s fuel efficiency, even with increased horsepower. Look for pumps designed to offer the best performance without excessive fuel consumption.

Durability and Build Quality

Opt for a well-constructed HPOP known for its durability. High-quality materials like stainless steel or advanced composites enhance longevity, especially under high-pressure conditions.

Installation Process

Consider how easy or complex the installation process is. Some HPOPs may require professional installation, which can add to the overall cost.

Brand Reputation and Reviews

Research different brands and read reviews from other Superduty owners. Reliable brands often offer guarantees or warranties that assure quality and customer satisfaction.

Budget Constraints

Define your budget and weigh it against your needs. High-performance pumps can be pricey, but sometimes, investing more upfront saves on maintenance costs long term.

Aftermarket vs. OEM

Decide whether to go with an Original Equipment Manufacturer (OEM) part or an aftermarket upgrade. Aftermarket options might provide better performance enhancements but remember to check their reputation for reliability and quality.

By considering these factors, you can select an HPOP that not only meets your performance goals but also ensures the longevity and efficiency of your Superduty truck.

What are the potential upgrades to consider when replacing an HPOP, such as larger injectors and turbo?

However, every factory injection system has its limits—and the 7.3L’s is no different. Once you venture beyond the 550-rwhp range (or, as a general rule of thumb, go larger than a 250cc injector), you run the risk of the stock high-pressure oil pump not being able to keep up. And if you’re unable to maintain high-pressure oil volume being delivered to the injectors, you’ll never realize the full potential of a big set of sticks. To remedy this situation and fully enjoy your truck, you’ll either need to add a higher volume HPOP or run dual pumps.

But what about other performance enhancements? Are you considering larger injectors and turbo upgrades? These modifications can significantly boost your truck’s power and efficiency. In recent years, 300cc or larger injectors equipped with 200-percent over nozzles have proven capable of supporting 650-rwhp or more and provide great streetability with proper custom tuning. Yet, they require a larger displacement high-pressure oil pump or dual HPOP’s to support them.

Additionally, upgrading your turbo can complement these changes, enhancing airflow and further maximizing horsepower gains. With a set of 350cc injectors fitted with 200-percent nozzles on the way, a truck owner must ready their highly modified 7.3L’s injection system for the increased high-pressure oil demand that follows. This preparation ensures the truck is not only powerful but also reliable for everyday use.

Is the owner considering upgrading to larger injectors and a turbo, or are they keeping these components stock?

The owner is contemplating the possibility of installing larger injectors and a turbo, weighing the benefits against keeping the stock components.

What are your plans for your truck concerning performance upgrades?

The plan is to explore potential upgrades, focusing on whether to enhance the truck’s performance with aftermarket parts or maintain the current setup.