Midway through model year 1998, the Dodge Ram switched from the 6BT to the ISB to meet updated emissions requirements. Like other ISB's, these engines started out using the Bosch VP44 rotary injection pump. The VP44 setup meant that timing and fuel could be precisely controlled, which led to cleaner emissions. However, VP44 failure rates were higher than the older P7100 injection pump. The compression ratio in these engines was 16.3:1. The 1998–2000 ISB was rated at 215 horsepower (160 kW; 218 PS) and 420 pound-feet (569 N·m) when equipped with the 47RE automatic transmission. The 1998 ISB was rated at 235 horsepower (175 kW; 238 PS) and 460 pound-feet (624 N·m) when equipped with the manual transmission. The 1999–2000 ISB was rated at 235 horsepower (175 kW; 238 PS) and 460 pound-feet (624 N·m) when equipped with a manual transmission. For the 2001–2002 model years, a standard output and a high output ISB Cummins engine were offered. The standard output, which was the same as the previous engines was rated to 235 horsepower (175 kW; 238 PS) and 460 pound-feet (624 N·m) when equipped with either a manual transmission or automatic. The high output ISB was rated at 245 horsepower (183 kW; 248 PS) and 505 pound-feet (685 N·m), with only a NV5600 six-speed manual transmission available. The high output engine was different in a few ways from the standard output engine; it had higher compression (17.1:1), powdered metal valve seat inserts, a larger flywheel, the Bosch fuel system was reworked to allow higher fuel flows, and fuel-injection timing was altered. Also in 2001 a new cam gear was introduced thus eliminating the need for a crank position sensor on the later 01-02 models.[WIKI]
|