The Cat C9 ACERT™ engine used in the 336D2 meets emission standards equivalent to U.S. EPA Tier 2. (A Tier 3-equivalent kit is also available if required.) The C9 engine uses precise electronic fuel and air management to ensure optimal performance and excellent fuel economy under all operating conditions. The engine runs at a constant speed of 1700 rpm, further improving fuel economy and reducing noise levels without compromising machine production. The 336D2 features a new three-stage fuel filtration system that effectively removes harmful contaminants contained in poor-quality fuel, thereby increasing machine uptime and extending the service life of fuel system components.