Dodge Truck HEMI Specsby James Rutter
Chrysler, the parent company of Dodge, first manufactured a "HEMI" or hemispherical head engine, for automobiles in the 1950s (the company had previously installed hemi-type engines in WWII era fighter planes). This engine layout enables more efficient airflow into each cylinder's combustion chamber, which increases performance. During the 1960s, Chrysler produced a second version, for use in NASCAR racecars and the muscle car Dodge Charger. In the early 2000s, the company began offering the HEMI motor in Dodge trucks.
Dodge installed the 5.7 liter HEMI engine in the Ram 2500 and 3500 pickup trucks starting in 2001. Starting in 2002, Dodge has made this HEMI engine an option in all Dodge Ram pickup trucks (the 1500, 2500 and 3500). From 2004 to 2009, Dodge began offering the HEMI engine in the Dodge Durango sport utility vehicle (SUV). The company discontinued the Durango for model year 2010, but will bring the Durango back into production with HEMI engine availability in 2011.
Dodge first offered the HEMI engine in its trucks as a 5.7 liter (about 350 cubic inches) displacement eight-cylinder, or V-8. This overhead valve engine consisted of an iron block with aluminum heads that used two valves per cylinder, for a total of 16 valves. The company made slight performance enhancements to the 5.7 HEMI in 2009; all models since contain this engine, as opposed to the first generation 5.7 liter HEMI produced from 2003 to 2008. According to the Allpar website, some of these upgrades included variable cam timing and changes to the intake manifold. These changes resulted in a higher compression ratio, greater horsepower and more torque at a lower engine rpm.
Output and Performance
Dodge trucks equipped with the first generation (2001-2008) 5.7 liter HEMI generate 345 horsepower at 5,600 rpm and 375 lb-ft of torque at 4,400 rpm with a compression ratio of 9.6:1. Second generation HEMI truck engines (2009-present) topped out at 390 horsepower at 5,600 rpm and 407 lb-ft of torque at 4,000 rpm with a compression ratio of 10.5:1. The Environmental Protection Agency rated the first generation 5.7 liter HEMI truck engine in a Dodge Ram as capable of a gas mileage of 17 mpg during highway driving and 13 mpg during city driving conditions. Second generation 5.7 liter HEMI truck engines in a Dodge Ram achieved a slightly higher highway driving efficiency of 19 mpg, while still getting 13 mpg under city conditions. According to Motor Trend magazine, a 2003 Dodge 1500 Ram pickup equipped with the HEMI engine could accelerate from 0 to 60 mph in 6.8 seconds and clock 89 mph in the quarter-mile with a time of 15.11 seconds. Edmunds reports that a 2009 Dodge 1500 Ram pickup equipped with the second generation HEMI could go from 0 to 60 in 7.6 seconds and take the quarter-mile in 15.6 seconds with a speed of 87 mph.
- red truck engine image by Christopher Nolan from Fotolia.com