All-Terrain Vehicle

An air intake system having a turbocharger and an intercooler provides combustion air for an internal combustion engine of an all-terrain vehicle. The all-terrain vehicle includes a straddle seat, and the he intercooler is mounted above the internal combustion engine. The intercooler has a plurality of pressurized air crosspipes defining an intercooler plane. An intercooler attack angle of the intercooler plane relative to horizontal is greater than or equal to 80° and less than 90°. The air intake system includes an intake pressure relief system with a pressure sensor and a pressure relief valve. When the pressure sensor senses an onset of an overpressure event, the pressure relief valve is opened. The turbocharger housing is integrally formed with the exhaust manifold, and the exhaust manifold has flange gaps between exhaust intake ports, which allow thermal expansion difference between the cylinder head and the exhaust manifold.