Unique “Cobra Head” Downpipe Boosts Output on 2015 Ford Power Stroke
Fluid Dynamics Computational Modeling Results in Unusual Shape
Trucks are all about function, so when it comes down to the choice between making something pretty or functional, the scales often tip to the latter. In the case of the 2015 Ford 6.7L Power Stroke V-8 engine, computational modeling was used to determine the optimum shape of the exhaust downpipe for maximum power and torque, resulting in what Ford calls a “cobra head” pipe. The redesigned exhaust downpipe helps the 2015 Power Stroke engine achieve a 40hp and 60–lb-ft boost over the 2014 model, bringing total output to 440 hp and 860 lb-ft.
The downpipe shape was modeled to minimize the number of kinks or sharp turns in the exhaust system, which increase pumping losses, reduce efficiency, and impede exhaust flow. Hundreds of hours of advanced fluid dynamics and computer modeling were employed to come up with the optimum shape for the downpipe.
The 6.7L Power Stroke V-8 is also unique in the HD pickup class in that it employs reverse-flow heads, with the exhaust or “hot” side inboard and the intake side on the outboard of the engine. This design was chosen for quick turbo spool-up and direct mounting of the turbocharger to the engine block, reducing potential vibration.