You probably know about the 5.9L Cummins and the 6.7L Cummins engines, but there is another Cummins engine that you’ll find in pickup trucks, and that’s the 5.0L Cummins used in the Nissan Titan XD. While it might not be as popular as the bigger Cummins engines found in Ram trucks, it’s still a pretty solid engine with some cool innovations that give it great power output and low emissions output.
To start this off, I want to clarify that the 5.0L Cummins is an engine that exists in two forms: the commercial version and the Nissan version. We’ll mostly be focusing on the Nissan version today, which according to Nissan and Cummins, shares about 70% of its internal components with the commercial version of the engine. Although it shares a large portion of the components, it took years for Cummins and Nissan to finally bring this engine to market in their Titan XD.
Why Nissan Trucks?
You might be wondering how the 5.0L Cummins ended up in Nissan’s truck, considering Cummins engines have historically been used in Ram trucks? That takes us way back to around 2009ish when Cummins was developing an all-new light-duty diesel engine that was supposed to be debuted in the Ram 1500 by 2010 but was later delayed.
“Chrysler’s delay has no impact on the [light-duty diesel] engine,” said Mark Land, director of public relations at Cummins. “We’re still moving forward with development, we’re just pacing it differently.” So, basically, Cummins was developing an engine that they presumed would be used in Ram trucks given their long history with supplying engines for their heavy-duty Ram trucks, but they weren’t locked into that, as they publicly stated that other companies were interested in their upcoming light-duty diesel engine.
“We have other customers who are interested in the engine, including Nissan,” Land said. “We’re also talking to others about the engine.” Of course, this was after Nissan had announced its partnership with Cummins. Nissan wanted to use diesel engines in their upcoming line of light commercial vehicles that were supposed to start production in 2010.
So, looping back around: Cummins was developing a light-duty diesel engine that was supposed to be used in the Ram 1500, but they were also open to supplying the engine to other companies, including Nissan, who they already had a partnership with for their light commercial vehicles.
Fast forward to late 2013, and Nissan publicly announced that the next-generation Titan would be available with the 5.0L Cummins engine. Up to this point, Cummins was still developing a version for commercial vehicle customers. The whole goal with this engine was to bridge the gap between a 1500 truck and a 2500 truck. This engine from Cummins, combined with their next-generation Titan trucks, was supposed to be more capable than an F-150, Silverado 1500, Ram 1500, or Tundra, but not quite as cumbersome as a heavy-duty pickup.
There was really a gap in the market, and light-duty diesel trucks were supposed to fill it, but that market ended up not being quite as big as Nissan had expected. More on that later, though.
But that loops us back around to the original question: why didn’t Ram use this engine in their 1500 trucks? And the answer is actually really simple: fuel economy. According to Ram, their research showed them that customer’s expected superb fuel economy from a 1500 diesel truck. So, rather than going with the 5.0L Cummins, they opted to develop their own engine with Fiat’s VM Motori, which was the EcoDiesel engine.
This article isn’t about the EcoDiesel, so we’re not going to get into that, but basically, they developed the EcoDiesel because they wanted more fuel economy than what the 5.0L Cummins was going to deliver.
Now that you have an idea of why this engine ended up in Nissan trucks instead of Ram trucks let’s take a look at the engine itself and what makes it such an interesting platform.
What makes the 5.0L Cummins so different from Cummins engines you’ll find in other pickup trucks is the fact that it’s a V8, whereas the 5.9L and 6.7L Cummins are both inline-six engines. Despite having a vastly different configuration from the Ram’s Cummins engines, it features many of the same design characteristics. Most notably, it features a Compacted Graphite Iron block, or CGI for short, which is the same durable and relatively light-weight block material used on 5th gen Cummins powered trucks.
For the engine to be lightweight compared to other diesel engines, everything needs to go on a big diet. That’s part of the reason that this engine uses a CGI block, as well as aluminum cylinder heads. The overall thickness of the block is also optimized for this application because the target power is much lower than the bigger diesel engines such as the 6.7 Cummins.
On top of the focus on weight, this engine was designed to be similar in its physical size to a gas V8 engine, which made it much easier to fit into 1500 applications like the Titan. All of that adds up to an engine that weighs around 900lbs when dry.
On top of the weight savings benefits, this engine features thick composite valve covers, which help to contain some of the noise. You have to remember that this engine was designed for half-ton trucks, which see a lot less work-related use and a lot more daily driving, so overall noise, vibration, and efficiency were really important to Nissan.
Something I found really interesting is that Cummins decided to give this engine four head bolts per cylinder, which, as you might know, is something Navistar did on the 6.0L Powerstroke, and that ended up being a complete disaster. With that said, though, the 5.0L Cummins doesn’t seem to have any of the same issues that plagued the 6.0L.
Inside the engine, you’ll find cast aluminum pistons with piston oil squirters underneath them to help keep them cool. Bore and stroke measure at 94mm and 90mm, respectively, with a compression ratio of 16.3:1 to top it all off. Ceramic glow plugs by Bosch are designed for quick start times and to last the lifetime of the engine without any maintenance.
In terms of the injection system, we’re looking at a system supplied from Bosch. Starting at the pump, it’s a CP4.2 pump, which is the same injection pump you’ll find on the 6.7L Cummins and the LML Duramax. The injection pump is supplied with fuel from a chassis-mounted electric lift pump. Those two combined supply the common rail injection system with around 29,000psi of injection pressure.
While the new fuel injection systems used of modern diesels are very capable and efficient, the Bosch CP4.2 is well known for being very sensitive to fuel quality. To help protect the entire fuel system, an advanced Cummins two-stage fuel filtration system is used, which provides significantly better fuel filtration by using the latest NanoNet media from Cummins Filtration. The NanoNet filter media reduces fuel-flow restrictions while simultaneously trapping more than 99% of all particles as small as 4 microns.
Even with that, though, the CP4.2 pump is a dangerous failing point. If the pump self-destructs, it will send metal fragments through the lines and rails, into the injectors, and then out the return system. Detecting this failure before it happens is basically impossible, and by the time it’s through, you’ll be need to replace the pump, lines, rails, injectors, and more. It gets really expensive really fast, so it’s a little unfortunate to see this pump used on the 5.0L Cummins, but it makes sense because it’s one of the most popular high-pressure fuel pumps used on common rail injection systems in pickup trucks.
All of that is topped off with piezoelectric injectors that can fire up to 7 times per combustion event. One of the big benefits of piezo injectors is how quiet they are, which again is something that Cummins and Nissan wanted to focus on to help improve drivability with the Titan XD.
Twin Turbo System
That brings us to the turbocharger, which is one of the more interesting parts of the 5.0L Cummins. This system comes from Holset, and it’s known as the M2 Dual Stage turbo. This is simply a twin-sequential system that uses one small turbo and one big turbo. This design provides excellent performance throughout the entire powerband. A smaller turbocharger provides quicker throttle response and acceleration and adequate performance for lower airflow scenarios. The larger turbocharger provides better performance at higher engine speeds or under heavy loads.
What blows my mind is the fact they fit this entire twin-turbo system in the valley of the engine under the intake manifold. Helping the two turbos work together is an electronically actuated wastegate system with a patented “Rotary Turbine Control” valve that operates the opening of ports during four main operating modes: Low-Pressure Single-Stage Turbo Mode, High-Pressure Two-Stage Turbo Mode, Wastegate Mode which maximum engine power output, and a Regeneration Mode.
What’s a little strange is that some of the early reports before the Titan XD launched stated the engine would be using a variable geometry turbocharger setup, but the turbo system isn’t variable geometry at all. In fact, part of the reason they developed this entire system was to have a viable alternative to a variable geometry turbo.
Jonathan Wood, executive director, research and engineering, said: “Advances in air handling technology and improved system integration continue to provide new turbocharging solutions that enable customers to achieve their emission and efficiency targets without compromising engine performance. Highly efficient and highly durable, this pioneering technology offers a smart alternative to Variable Geometry. Nissan is the first to benefit from the new technology. Working in partnership with the Cummins Engine Team and Nissan, we have developed a custom system solution, which is tailored to the customer’s operational requirements.”
While this turbo system is unique, interesting, and very efficient, it’s a little problematic. More specifically, around 12,000 2016 Titan XDs were recalled for turbocharger lubrication issues. Due to a manufacturing defect, low oil pressures would result in the turbo being starved of lubrication. This could cause the turbine wheel to come in contact with the turbo housing, and when this happens, metal shavings can be sent through the turbo and into the engine, leading to potentially catastrophic engine damage.
All of this equals out to pretty decent performance for a relatively small diesel truck engine, at 310hp and 555lb-ft in the Titan XD. Strangely enough, on the Cummins website, the ISV5.0 is actually rated lower in terms of power, so they definitely turned it up a bit for the Nissan application as compared to the commercial applications.
That being said, the 310hp figure might actually be a little underrated, with some of Titan XD trucks putting down upwards of 280whp. So, either the engine is underrated, or the A466ND Aisin transmission is just really good.
All of that loops us around to the part of diesel engines that everyone loves to hate, and that’s the emissions systems. On the bright side, the advanced emissions systems combined with the advanced turbo leave the 5.0L Cummins with impressively low emissions outputs, but those same emissions systems are also the biggest failing points on the 5.0L.
It features all the systems you’re familiar with on modern common rail injection injections, which is a diesel particulate filter, exhaust gas recirculation system, and a selective catalyst reduction system with diesel exhaust fluid injection.
We’ve covered diesel particulate filters in other articles, but to briefly recap, the job of the DPF is simple: capture excessive exhaust soot and then burn it off occasionally through a regeneration mode. It does the regeneration through two modes: an active regeneration mode and a passive regeneration mode.
Passive regeneration occurs when the exhaust temperatures are naturally high enough to oxidize the soot collected in the DPF faster than the soot is collected. This typically occurs when the temperature of the DPF is above 300°C or 572°F. This occurs during highway driving or when driving with heavy loads.
Since passive regeneration occurs naturally, it is considered to be normal engine operation.
Active regeneration occurs when the exhaust temperatures are not naturally high enough to oxidize the soot collected in the DPF faster than it is collected. This works by injecting a small amount of diesel fuel into the exhaust stream, which is then oxidized by the diesel oxidation catalyst. It injects the fuel into the exhaust stream using the late injection method, which is simply firing the injectors late in the exhaust stroke. The oxidation of this additional fuel raises the exhaust temperatures to approximately 550°C or 1,022°F, which is needed to regenerate the DPF.
The EGR system is used to lower combustion temperatures by basically diluting the air/fuel mixture with a small amount of exhaust gas, and that’s paired with an EGR cooler which cools the exhaust gases before they enter back into the intake.
And last but not least, the SCR system works to reduce emissions by spraying diesel exhaust fluid into the exhaust system, where it is converted to ammonia which then breaks down nitrogen oxide into nitrogen and water.
Unfortunately, all these emissions systems have some issues. Most notably, the DEF system has issues with the DEF pump failing, which is most often caused by contaminants getting into the pump. If this pump fails, it can put your truck in a limp mode and, if left untreated, can create even more issues.
On top of that, the EGR coolers are known for failing, and the EGR valves are known for sticking. The EGR valve gets stuck open or closed from carbon and soot buildup.
In terms of performance, you can see upwards of 700lb-ft of torque and around 400 to 450 horsepower from the 5.0L Cummins when deleted and tuned. While this isn’t a particularly great power figure, especially when compared to larger diesel engines like the 6.7L Cummins, it makes sense in this context, especially when you consider the unique turbocharging system on this engine which is mostly focused on efficiency rather than power.
With that turbo system swapped out for something more aggressive like a single turbo setup, you can see upwards of 550whp and 900lb-ft of torque, which isn’t half bad. Of course, a similarly modded diesel in a heavy-duty truck will definitely make more power, but considering this is a smaller engine, it’s fairly impressive.