Mack E7 Engine Specs

by Tim McQuade
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The E7 engine was first produced by Mack in 1988. It is a heavy-duty, inline six-cylinder, diesel engine that saw use primarily in commercial 18-wheel trucks. The engine underwent some modifications over the years and was in production from the late 1980s into the 2lst century.

Power Specifications

The E7 was a 12-liter -- 728-cubic-inch -- four-cycle engine that utilizes direct-injection technology. The total power rating of the E7 was between 250 and 454 horsepower at 1,700 to 1,800 rpm. In its 250-pony garb, the torque was 975 foot-pounds at 1,200 rpm. In its 300-horsepower spec, torque is 1,160 foot-pounds at 1,200 rpm. Torque jumped to a massive 1,360 foot-pounds in the E7 with 350 horses. In its 400-horsepower design, torque peaked at 1,460 foot-pounds at 1,250 rpm. The highest-output E7 engine churned out 454 horses and twisted 1,660 foot-pounds of torque at 1,200 rpm.


The original E7 was turbocharged and featured a body-mounted, air-to-air after-cooled system. In 1990, Mack developed an electronically controlled and variable-injection timing system that it dubbed the Econovance Variable Injection Timing system and it optimized fuel efficiency and reduced emissions. Mack used this system exclusively on the E7 engine. In 1991, Mack added another modification to the E7, the High Swirl/Moderately High Injection Pressure Combustion System, enhancing the mixing process of air and diesel fuel. This improved combustion efficiency and fuel economy while reducing emissions, maintaining proper oil viscosity and expanding oil change intervals.

Other Information

The E7 engine series grew exceedingly popular since its introduction in 1988. Because of its relative popularity and quality performance over the years, Mack produced a total of 16 different versions of the E7 line. In 1999, Mack introduced the E7-460, which sported the Mack E-Tech technology. According to the official Mack Trucks website, “The E7 boasts the industry's best horsepower-to-weight ratios for customers concerned with achieving maximum productivity.” After its introduction in 1989, the E7 was designed to meet the Environmental Protection Agency’s emission standards for 1990, and has since undergone modifications to meet increasingly stringent emissions rules.

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