6.4L Power Stroke vs. 6.7L Cummins vs. 6.6L Duramax

 

Power Stroke

6.4L Power Stroke

Cummins

6.7L Cummins

Duramax

6.6L Duramax LMM

Production Years:

2008 - present

2007.5 - present

2007.5 - present

Manufacturer:

International

Cummins

Isuzu

Block/Head Material:

Iron/Iron

Iron/Iron

Iron/Aluminum

Configuration:

V-8

Inline 6

V-8

Displacement:

6.4 liters, 390 cubic inches

6.7 liters, 408 cubic inches

6.6 liters, 403 cubic inches

Compression Ratio:

16.7:1

17.3:1

16.8:1

Bore x Stroke:

3.86 x 4.13 inches

4.21 x 4.88 inches

4.06 x 3.90 inches

Injection System:

high pressure common rail

high pressure common rail

high pressure common rail

Aspiration:

Twin sequential turbochargers

Variable geometry turbocharger (VGT)

Variable geometry turbocharger (VGT)

Valvetrain:

overhead valve, 4 valves per cylinder

overhead valve, 4 valves per cylinder

overhead valve, 4 valves per cylinder

Weight:

approx. 1,150 lbs

N/A

approx. 835 lbs.

Peak Horsepower:*

350 hp @ 3,000 RPM

350 hp @ 3,013 RPM

365 hp @ 3,100 RPM

Peak Torque:*

650 lb-ft. @ 2,000 RPM

650 lb-ft. @ 1,500 RPM w/ auto trans
610 lb-ft. @ 1,500 RPM w/ man trans

660 lb-ft. @ 1,800 RPM

Reputation:

The latest addition to the Power Stroke family features twin turbochargers for lag-free operation. Keeps Ford's "hard working truck" image alive and has the highest in class tow capacity. Suffers from poor fuel economy due to new emissions equipment that makes the 6.4L a "clean diesel".

The new 6.7L Cummins comes from the factory equipped with an exhaust brake. New automatic transmission is much better than older versions, which were weak links in the drivetrain. Trucks that are equipped with manual transmissions will now have to settle for a de-tuned motor. Suffers from poor fuel economy due to new emissions equipment that makes the 6.7L a "clean diesel".

The new 6.6L Duramax defeats the competition in horsepower & torque, though it also suffers from poor fuel economy due to the new emissions equipment required to make the 6.6 a "clean diesel". All brands are suffering from poor fuel economy due to the new emissions standards that must be met. The LMM still features the Allison 1000 6-speed automatic transmission.

Applications:

2008 - present Ford Superduty.

2007.5 - present Ram 2500 & 3500.

2007.5 - present Chevrolet & GMC HD 2500 & 3500 trucks.

 

*Peak horsepower & torque refers to the highest advertised power output during the engine's production.

 

 

 

You may also be interested in the following articles:

6.7L Power Stroke vs. 6.6L Duramax

Automatic vs. Manual Transmission

Diesel Tech