The T444E is one of the most popular engines found in school buses between 1994 and 2004. This engine was used as the base platform for Ford’s 7.3 Powerstroke as well, sharing almost all mechanical components. The T444E replaced the 7.3 IDI that was produced between 1982 and 1993, and is an all new engine with essentially no parts in common. It featured an turbocharger with a charged air cooler, hydraulic electronic unit injection (HEUI), and was all electronically controlled.
In school buses, this engine has a wide range of power ratings, from 175 to 275 horsepower and torque ratings over 500 lb/ft. It was typically mated with the AT545 transmission, as the lower power (compared to bigger alternatives like the 8.3 Cummins or Navistar’s DT466E) could be handled without a more expensive unit.
In Ford trim, the Powerstroke engine was tuned to allow higher RPM operation and were shipped with a 275 horsepower rating. These engines were popular with tuners as massive power increases could be had relatively simply by upgrading the injectors, turbocharger, and using a performance tuning ECM. Reliable engines pushing 700hp or more could be built with a few thousand dollars in parts.