The Cummins engine is one of the most well known high performance diesel engines on the market. Since the 1980’s, it has been the gold standard for owners and drivers who want the most out of their pickup trucks. The power and torque produced by the Cummins is unmatched by most others and that is why it has remained at the top of the heap for trucks that need serious torque and power. Its reputation is well deserved, as is evidenced by the fact that there are so many of them still in production that are still sought after by professional and recreational truckers alike.
Figure 1: The Cummins diesel engine has been a stalwart of the Dodge RAM from the 80’s until the present. Source: BestOfAuto.com.
While any Cummins engine will blow most other diesels out of the water, there is a fairly wide variety of models. Depending on how much power you want or need, it can be difficult to know which model will best suit your needs. That’s why we have put together a list of the best Cummins engines to help you decide how your money will be best spent. Not everyone is going to need a massive Turbo Diesel, but if you do, you will want to understand why.
Since there are a few different popular varieties of these powertrains, wading through them can be a challenge. Knowing what your power and towing needs are will go a long way in helping you make your decision. By reading our list of the best Cummins engines, you can figure out how these beasts can best suit your driving and work habits with your truck.
Sources: Cummins.com; PassageMaker.com.
What Makes the Best Cummins Engine?
The Cummins diesel engine was first introduced to the consumer truck market in 1989. It was included as an option on Chrysler’s RAM trucks and was immediately popular for its longevity and massive amount of power. This comes from the solid, overbuilt construction that is able to generate over 400 lb-ft of torque on even some of the smaller models. Because of this, it quickly became the gold standard for work trucks and any owner who spends a lot of time towing.
CLICK HERE TO WATCH A VIDEO ON THE BEST CUMMINS ENGINE TO BUY
Perhaps the greatest advantage of the Cummins engine is its durability and longevity. There are almost 10,000 people who can boast that they are in the Cummins High Mileage Club. This means that their Cummins has crested the one million mile mark. The best Cummins engine will have the signature cast iron block and head that has contributed to its reliability. It will also utilize the steel timing gear that connects the cam and the head instead of a belt. This allows for more torque and a more durable connection point for these crucial parts.
Figure 2: The Cummins in-line configuration is just one of the reasons it is so durable and powerful. Source: TruckTrend.com.
One of the other things that makes the Cummins engine great is that it is an incredibly tunable platform. There are all kinds of mods that can increase the performance and power. This is partly due to the Bosch P7100 mechanical injection pump. This pump, also known as the P-pump, is a versatile injection pump that uses six plungers to push fuel through the delivery valve and into the cylinders themselves. The way it is set up allows for a lot of mods that you can do without ever turning a wrench. This includes fuel plates that are cut in ways that increase the flow of fuel and can add up to 70 horsepower. The best Cummins engine will have this P-pump and allow you to tune your truck exactly how you want it.
Sources: HighMileage.Cummins.com; MotorBiscuit.com; Jalopnik.com; TruckTrend.com.
How Did We Pick the Best Cummins Engine?
We spoke to an engine specialist at West Coast Diesels who told us that “the Cummins is just so straightforward. There’s almost nothing that can come loose or fall apart and that’s why they’re so popular with towers and heavy duty drivers. They’re pretty much indestructible and it would take a lot to kill one.”
This durability is what we looked for when choosing the best Cummins engine. While all of them have the reputation for being well built and hardwearing, the most popular models are the ones that are still around and crushing pavement years and years after they were first produced. This longevity is attributed to their simplicity and utilization of heavy duty materials.
Figure 3: The simplicity and durability of the Cummins engine is what has contributed to its popularity over the years. Source: AutoWise.com.
We also picked the best Cummins engines based on how much power they are able to put out. Odds are, if you are looking for a Cummins for your truck, you have some serious torque needs and do a lot of towing. By choosing a motor from our list, you can be sure that your truck will be able to pull pretty much anything you throw at it, and for a very long time. Massive torque is what makes the best Cummins engine stand out from the rest of the diesel engine pack.
Sources: MechanicGuides.com; DieselResource.com; Interview with engine specialist at West Coast Diesels conducted 12/7/2020.
1. Cummins 6.7L Turbo Diesel
Figure 4: The 6.7L Turbo Diesel is the most powerful diesel engine for the Dodge RAM. Source: Cummins.com.
The Cummins 6.7L Turbo Diesel is the current incarnation of this legendary diesel engine. It is packed with features that make it the best Cummins engine that is currently on the market. Because of its prestige and durability, many RAM owners are choosing to upgrade to this bigger, more powerful model from the one that came standard in their early 2000’s truck.
The thing that really makes this the best Cummins Engine is the variable geometry turbo. This turbo unit varies the exhaust flow at the turbine wheel, so it can still function as a smaller turbo unit even at lower RPMs. This helps with the engine’s responsiveness and allows the engine to have the best possible performance, even at lower speeds and RPMs. This turbo unit also helps aid in braking power by changing the nozzles position and using the engine’s own restriction to slow it down. This can save the stock brakes and help mitigate some of the wear and tear that comes with the larger engine.
CLICK HERE TO WATCH A VIDEO COMPARING THE 6.7L CUMMINS WITH THE 5.9L VERSION
The overall power and torque that comes from the 6.7L is unmatched in the industry. With up to 385hp and 900 lb-ft of torque, this is a beast of an engine. Its responsive turbo and high-pressure injection make it a must for any heavy-duty truck driver.
Sources: Cummins.com; DieselNet.com; DrivingLine.com.
2. Cummins 5.9L ISB
Figure 5: Although the 5.9L ISB is slightly less powerful, it is still more than enough for even the most heavy-duty applications. Source: USEngineProduction.com.
The 5.9L ISB by Cummins is a smaller version of the 6.7L, but it still packs some serious power that most drivers will be more than satisfied with. At 325hp and 610lp-ft of torque, it has enough strength for almost any job that you can throw at it, while maintaining the reliability that the best Cummins engines are known for.
The turbo unit on the Cummins 5.9L ISB uses a fixed geometry turbo instead of the variable one that comes stock on the 6.7L model. The tradeoff on this is that it is not as responsive and doesn’t help contribute to the stopping power that the variable turbo is known for. However, the fixed unit is much more reliable and has fewer moving parts, which is exactly what the best Cummins engine should be focused on. If you are putting a Cummins in your truck, you are looking for an engine that is “set and forget,” and is going to give you the fewest headaches.
The 5.9L ISB also doesn’t have much in the way of emissions equipment except for a standard catalytic converter. This, combined with a lower pressure injector means that you will be less likely to blow a head gasket with heavy use. If you are looking for an engine that will be as reliable and durable as it can possibly be, this could be a fantastic option.
Sources: USEngineProduction.com; DrivingLine.com.
3. Cummins 5.0L V8 TURBO
Figure 6: The 5.0L V8 version of the Cummins engine is smaller but still incredibly moddable and powerful. Source: Cummins.com.
The Cummins 5.0L V8 TurboDiesel is the best Cummins engine for smaller trucks and drivers who don’t need as much pulling power. It utilizes a compacted graphite iron block for a durable construction that is still light enough for smaller applications. If you want an engine that will be less susceptible to noise and vibrations, it could be a great option.
The turbocharger in the 5.0L V8 is the Cummins M2 Two-Stage Turbo. It uses high injection pressure to give the most precise control of the in-cylinder combustion. This leads to superior fuel efficiency and almost zero emissions.
Just because the 5.0L V8 is smaller, that doesn’t mean it skimps on power. It still delivers 310 stock horsepower and 555lb-ft of torque due to the fuel system and the Two-Stage turbo. If you are looking for a good balance between performance and comfort, this could be the best Cummins engine for your truck.