Engine Configurations for Snowmobiles

A snowmobile comprising:

• a forward frame assembly defining an engine bay;
• an engine positioned within the engine bay, the engine having a plurality of intake ports positioned on an aft side of the engine and a plurality of exhaust ports positioned on a forward side of the engine;
• an air intake system coupled to the aft side of the engine, the air intake system includes an airbox having an air inlet that is positioned outboard of the engine bay, an air plenum positioned on top of the engine, a throttle valve assembly coupled between the airbox and the air plenum, the throttle valve assembly positioned outboard of the engine bay on a first side of the engine and an air runner assembly coupled between the air plenum and the engine, the air runner assembly including a plurality of air outlets each of which is configured to provide air to one of the intake ports;
• and
• an exhaust system coupled to the forward side of the engine, the exhaust system including an exhaust manifold having a plurality of exhaust inlets each of which is configured to receive exhaust from one of the exhaust ports and a muffler including an exhaust outlet positioned outboard of the engine bay on a second side of the engine that is opposite of the first side;
• wherein, each of the engine, the air plenum, the air runner assembly and the exhaust manifold is at least partially disposed within the engine bay.