The individual cylinder exhaust pipes (one per cylinder) from each cylinder head converge to a main exhaust manifold/collector which runs along the engine. The exhaust manifold is made up of several sections bolted end to end, usually one section covering a group of cylinders. Each section is fabricated from heavy-gauge steel (or cast sections) and the flanged joints between consecutive sections are bolted together with gasketed joints (laminated/steel gaskets) to give a gas-tight, yet semi-rigid, connection. The cylinder exhaust pipes connect to the manifold via flanged branches. The manifold has an outlet at one end (usually forward or aft end) which leads to the turbocharger(s) through the exhaust gas piping (with an expansion joint and, on multi-turbocharger engines, bellows). The joints allow relative movement but are strong enough to carry the weight and the exhaust pulse. On some engines there is an arrangement to isolate sections, and access covers/casing for cleaning. The sections are carried on supports anchored to the engine bedplate so thermal growth is controlled.

Because the manifold gets very hot in service (up to 400-500 deg C), the sections and the connecting exhaust piping grow substantially. To allow this thermal expansion:

• The flanged joints between sections may incorporate a slip (spigot) joint with a gasket, or each flange connection is made with expansion bellows (corrugated steel bellows) clamped back-to-back, so each section can expand axially relative to the next without stressing the flanges or the bolted joint.
• The single outlet connection to the turbocharger pipe is provided with a bellows/expansion joint and the manifold is supported on sliding supports/rollers so the whole manifold can grow freely along its length.
• The manifold is anchored at one end and allowed to expand towards the other end.
• On many modern engines each cylinder exhaust pipe is connected to the common manifold through individual flexible bellows, and the manifold itself is of the "collector with bellows" type so every pipe can move and still remain sealed. Internal sliding/lapped joints with heat-resistant gaskets are common where bellow lengths must be short.

Broken pieces of piston ring, piston crown material and scale from the combustion space can be carried by the gas flow into the turbocharger turbine, where they would damage the blades. To prevent this:

1. The exhaust manifold/collector is arranged with a change of direction and a large dead space/catch area so the heavy particles fall out of the gas flow under inertia/gravity and collect in a pocket, where they can be removed through access doors.
2. A perforated baffle/arrester or a grid/wire mesh is fitted part-way along the manifold or at the turbocharger inlet to filter out the solid particles before the gas enters the turbine.
3. The arrangement may include a "turbine guard" - a series of guide vanes/mesh at the manifold outlet to the turbocharger to stop large fragments.
4. The bottom of the manifold is provided with drain/catch pockets with access doors so that accumulated ash and any ring fragments are removed at every overhaul/maintenance.
5. On some engines the particles are collected by a metal or ceramic vertical plate just in front of the turbine inlet which intercepts them.

These measure prevent damage to the high-speed turbocharger rotor, which is a critical and expensive item.