40
Endurant HD N
Accelerating and Shifting
The delayed response of the CNG engine also impacts how the vehicle acceler-
ates and shifts through the gears. Drivers will notice that the engine does not
build torque as fast as a diesel engine, so accelerating and shifting gears
through an intersection from a stop or merging onto an expressway can take a
little longer; drivers will need to take this into account.
Cruise Gears
The Cummins ISX12 CNG engines operate at a higher RPM to develop the same
power as a diesel engine, so with this in mind the Endurant HD-N transmission
is programmed specifically for this engine to keep the engine at an optimal
speed to provide the best performance and efficiency. Unlike diesel engines that
operate in the 1000-1400 RPM range, the ISX12 engine operates in the 1250-
1650 RPM range. Drivers can expect the engine to run a bit faster and possibly
a gear lower than they are used to.
