EcoDiesel_vs_Cummins_lead

Right now in the half ton marketplace there is a lot of buzz around diesel. Thankfully, Ram introduced the EcoDiesel and consumers lined up to buy every single one they allocated. In response to the overwhelming consumer demand, Ram increased their allocation to 20 percent.

TITAN_PLATINUM_Fr_02_4_3Now, we have Nissan entering the half ton marketplace with the redesigned Nissan Titan with a diesel power plant under their hood. Not just any diesel either, it is a Cummins. Nissan is betting so heavily on this engine option, that all initial Titan offerings (the XD model) are Cummins powered trucks. Yep, you read that right, 100 percent diesel.

Ram felt the diesel option would be a small take rate and allocated a very small percentage of them to their trucks, where Nissan is betting big and only building diesels powered trucks initially.

2015 Ram 1500 Laramie Crew Cab 4x4 EcoDieselThese are very different marketing strategies from two very different companies. One company is a domestic company with a ton of full size truck heritage and they opted to use a foreign engine to power their truck. The other, a foreign manufacturer working on their second generation of full size trucks opting to partner with a domestic engine manufacturer. It is actually kind of funny if you think about it. You have domestic brand with a foreign engine and a foreign brand with a domestic engine.

We figured this was a good time to take a look at the two diesel offerings and see how they compare. Not only are their marketing strategies different, the two companies have very different intentions in mind when they designed or selected their engines. Hopefully, we can shed some light on the differences and help you make a decision which one is better for you.

(Click here for an in-depth article on the 3.0-Liter EcoDiesel or here for an in-depth article on the 5.0-Liter Cummins)

2015 Nissan Titan XD Cummins 5.0L V8 Turbo Diesel

 

Mind Set Differences

For Nissan, this new Titan is a statement piece. The truck market is very difficult to break into and gain any market share. From what we can tell, they really honed in on the premium truck owner who likes refinement and values the function of a truck. These are picky buyers, but buyers that aren’t afraid to spend a little money (as of time of print, pricing has not been announced yet.)

It is that feeling that the engine always has more to give. — Rich Miller, Nissan USA

“Our strategy for our diesel engine is to not only center on better fuel economy but we also have to deliver on the performance of a diesel engine. Where you get a lot of tenacity when you are accelerating or on a grade climb. It is that feeling that the engine always has more to give. You never run out and hit the top of the torque curve or top of the peek. It is always wanting to give you more than you ask for,” explained Rich Miller, Director of Product Planning and Titan Chief Product Specialist.

For Ram, they have an engine with a huge following. All we need to do is say Hemi and people instantly know who makes it and what we are talking about. So, for “all the power” there is a Hemi option. Ram looks at a diesel offering slightly different.

Great fuel economy who still wants to be able to tow. — Mike Cairns, Ram

“What we are doing with the diesel is offering an option to someone who is interested in great fuel economy who still wants to be able to tow. This [EcoDiesel] still has a 9,200lb tow rating. So, it is a truck that can do a lot of work,” said Mike Cairns, Chief Engineer, Ram Truck Brands.

The two comments above really highlight the different focus. Nissan is focused on performance with decent fuel economy and Ram is focused on fuel economy with decent towing.  It is interesting that the EcoDiesel option in the Ram, is able to tow 1,400 pounds less than the 5.7-Liter Hemi. (Diesel tows less than a gas engine.) At time of publishing, Nissan hasn’t announced fuel economy ratings, but we are expecting them to be less than the EcoDiesel and land somewhere mid pack within the truck segment. (Possibly in the 17 or 19 mpg city and somewhere round the 22 to 24 range on the highway.)

The EcoDiesel is a very small and compact engine that offers great performance for its size.

2015 Nissan Titan XD Cummins 5.0L V8 Turbo Diesel

 

Engine Architecture Similarities

Both engines have a “V” architecture. The differences come in at the angle of the V. The EcoDiesel is a 60-degree V6 whereas the Cummins is a 90-degree V8. Visually, the Cummins is a much wider engine which usually comes at a cost of additional weight. Nissan repeatedly comments that the front end of their truck is massive to fit the Cummins in there. This is what they are talking about. A very wide engine takes up a lot of room.

Banks630T-block

Photo courtesy of Banks Performance.

Both engines are modern engines with all the bells and whistles to reduce weight. Both use Compacted Graphite Iron (CGI) blocks and aluminum cylinder heads. A concern for us in the performance market, would be that both engines run four bolts per cylinder instead of six. If the 6.0 and 6.4 Liter Power Stroke had not run into so many head gasket issues, we probably won’t worry about it as a number of gasoline engines run four bolts per head.

These engines, also, feature dual overhead camshafts with one lobe per valve. The intake camshafts are driven by the crank with a timing chain on the Cummins. The exhaust camshaft is then driven from a gear to gear mesh with the intake camshaft. On the EcoDiesel, it is exactly the opposite. The exhaust camshafts are driven and they drive the intake.

One thing about modern diesels is that they all have the wonderful emissions equipment that we have all come to so thoroughly love… not. Both of these engine do feature the same DEF, EGR, SCR, and DPF systems. There really is no way around that until some major breakthrough happens.

Engine Differences

unique-2-stage-turbo-announced-nissan-titan-5-0l-diesel2Outside of the most obvious difference (V8 vs V6) probably the most pronounced difference between the two engines is the charge air system. The EcoDiesel runs a small variable geometer turbocharger that is packed very tightly into the valley. The 5.0 Cummins packs two turbochargers into the valley. The Cummins is running a Holset M2 two-stage turbocharger. According to Cummins Turbo Technologies, “The modulated two-stage system can have a high-pressure turbocharger far smaller than that of a conventional two-stage system, improving transient performance by reducing the turbocharger lag that affects both driveability and emissions.”

Getting on boost far quicker means more low end torque, but with the ability to pass the load from the little charger over to the large charger, the M2 system will, also, have more mid-range and top end performance than the EcoDiesel. While no dyno sheets have been released, we would assume the Cummins out performs the EcoDiesel start to finish.

The EcoDiesel runs a single Variable geometry turbocharger.

The fuel systems are slightly different as well. The Cummins is running a Bosch piezo fuel injector that is able to fire five times per combustion event. The EcoDiesel is running a Fiat system that is able to fire up to eight times per event. This slight difference could mean the EcoDiesel is slightly quieter at idle and low rpm than the Cummins.

For us in the aftermarket performance industry, there could be a major difference in electronic performance. The EcoDiesel is running a FCA (Fiat Chrysler Automobiles) engine control unit. If it is anything like the FCA unit in the Ram, tuning could prove to be very challenging. On the other hand, the 5.0-Liter Cummins will be running a Cummins engine control unit. Tuning companies have quite a bit of experience with “cracking” these and tuning will probably be out within a fairly short period of time.

Conclusion:

So, there you have it. If you need a truck that has good capability, but is quiet and gets great fuel economy, the Ram should be at the top of your list (to look at and test drive anyways). If you are someone who demands the power and fuel economy when you are working a truck, then the Nissan Titan should be at the top. The Titan will probably be a little more fun to drive while driving the truck daily, but both of the trucks should perform great in day to day situations. With a diesel engine under the hood of your half ton truck, it is really hard to loose.

EcoDiesel_15_front
Manufacturer: VM Motori
Configuration: 60 degree V-6
Head/Block Material: Aluminum cylinder head, Compacted Graphite Iron engine block
Displacement: 3.0 liters, 182 cubic inches
Compression Ratio: 15.5 : 1
Bore: 3.27 inches
Stroke: 3.60 inches
Valvetrain: 24 valve, dual overhead cam
Injection: 29,000 psi common rail
Aspiration: Intercooled, water cooled variable geometry turbocharger (VGT
Oil Capacity: 10.5 quarts with filter
Horsepower: 240hp @ 3,600 rpm
Torque: 420 lb-ft @ 2,000 rpm
Towing & Payload: 1,620 lbs max payload, 9,200 lbs max towing (2014 figures)
Nissan_Cummins82013_3
Manufacturer: Cummins
Configuration: 90 degree V-8
Head/Block Material: Aluminum cylinder head, Compacted Graphite Iron engine block
Displacement: 5.0 liters, 305 cubic inches
Compression Ratio: N/A
Bore: 3.7 inches
Stroke: 3.54 inches
Valvetrain: 32 valve, dual overhead cam
Injection: 29,000 psi common rail
Aspiration: Intercooled, Modulated two stage
Oil Capacity: N/A
Horsepower: 310 HP
Torque: 555 lb.-ft.
Towing & Payload: 2,000* lbs max payload, 12,000* lbs max towing.
* = subject to change