Engineering Explained looks at McLaren’s top-mounted exhaust

Engineering Explained is one of our favorite YouTube channels because Jason Fenske knows all the right questions to ask and answer. In his latest video, he travelled to Arizona to get details on the top-exit exhaust on the McLaren 600LT and 600LT Spyder. What did rerouting the exhaust to its new location mean and how does it compare to the 570S?

Weight

The top-exit routing is shorter than rear-exit, eliminating 18 pounds of tubing and reducing backpressure, helping the 600LT produce 30 more horsepower than the 570S. Eliminating the rear-exit exhaust means there’s no need for the fans used to remove heat from behind the rear bumper, saving an additional 10 pounds.

Aerodynamics

Moving the exhaust up top allowed McLaren plenty of room to make the rear diffuser as effective as possible. It’s part of a package of aerodynamic improvements on the 600LT that lead to an additional 220 pounds of downforce at 155 mph compared to the 570S. It also doesn’t impair the rear wing’s ability to create downforce, as it’s the outboard portions of the wing that are doing most of the work.

Inclement Weather

Yes, McLaren engineers took precipitation into consideration. There are drain holes that allow any water that enters the exhaust tip to exit under the car without damaging the engine.

Sound

This one is not as tangible, but moving the exhaust creates a more visceral driving experience, and that’s what a sports car is all about.