insugslinjer

Insugslinjer, or intake runners, are a set of tubes within an internal combustion engine’s intake manifold that connect the throttle body or air plenum to the intake ports of the cylinders. They are typically arranged as one runner per cylinder and can be made from aluminum, steel, or composite materials.

Their primary function is to deliver air to the cylinders efficiently while shaping the air flow to improve volumetric efficiency. The runner length and diameter influence resonance and air velocity; long runners generally boost low-end torque, while short runners favor high-end power and higher RPM operating range. The design of the intake runners interacts with cam timing, port geometry, and throttle response to shape the engine’s torque curve.

Design considerations include matching runner lengths to engine displacement, cam timing, and port geometry; ensuring nearly equal lengths for uniform air distribution; and controlling heat transfer from the engine to the intake charge. Plenum volume and runner diameter also affect throttle response and peak power. In some engines, multiple runner configurations are used to balance flow characteristics across RPM bands.

Many engines employ variable-length intake runners (VLIR) or switching manifolds that alter the effective path length with valves or flaps. This allows a broader power band by combining the benefits of both long and short runners. In production engines, insugslinjer are integrated with the intake manifold, fuel delivery, and sometimes turbocharging, and they are tuned during development for target performance and emissions.

Common issues include air leaks at gaskets, cracks in runners, or mismatched lengths leading to uneven intake flow, rough idle, or reduced performance. Proper design and maintenance help ensure consistent air distribution across cylinders.