The McLaren 600LT features a top mount exhaust, but it’s not just for looks, or to sound good, it’s quite a functional change to the design of the 570S in upgrading to the long tail. This video will focus on five main questions, clarifying the advantages of a top mount exhaust://Engineering Explained
Weight is actually a real advantage of a top mount exhaust. In the 570S, the exhaust comes out each of the sides of the V8 engine, travels back, up and over the transmission housing, and then back down, where it’s split between the two sides before exiting the rear of the vehicle.via: Engineering Explained
On the 600LT, this path is significantly shorter, and cuts off when the exhaust routes over the transmission, straight out the top. Not only does this reduce back pressure within the exhaust, helping the 600LT’s additional 30 horsepower over the 570S flow more freely, but in exhaust piping alone it saves 8 kg.
A further 4.6 kg is saved as a result of better cooling characteristics. In total, 12.6 or about 28 pounds are saved through a revised exhaust. How was McLaren able to pull weight and improve powertrain cooling? Well in the 570S the bumper has fans at each corner to help blow out the hot air generated by the exhaust. This hot air pools within the bumper and soaks the area in heat. The electric fans, weighing 4.6 kg, are no longer needed with the top mount exhaust, and rear of the car remains cooler.//read more: Engineering Explained