An integrated exhaust manifold for use with an internal combustion engine and dual scroll turbocharger. The integrated exhaust manifold includes a first exhaust passageway fluidly connected between a first pair of piston cylinders and the dual scroll turbocharger for transporting exhaust gas from the first pair of piston cylinders to a first input of dual scroll turbocharger. The integrated exhaust manifold includes a second exhaust passageway fluidly connected between a second pair of piston cylinders and the dual scroll turbocharger for transporting exhaust gas from the second pair of piston cylinders to a second input of the dual scroll turbocharger. The second exhaust passageway is fluidly independent from the first exhaust passageway and the first and second exhaust passageways are positioned to define a septum area therebetween. A cooling system having a septum cooling jacket is use to cool the septum area between the first and second exhaust passageways.