For our turbo issue, we’ve compiled some of the most outrageous turbocharger setups we have ever seen, past and present. But taking a turbocharger off a freight train won’t get you a spot on this list, because functionality is also assessed—not just impressively large sizing. Here you’ll see killer single turbos, compound turbochargers in double and triple arrangements, and even superchargers. The best part is that all of them are functional and produce massive amounts of power. Cummins, Duramax, and Power Stroke engines are all represented, and we’ve even included the most outrageous setup we’ve ever seen: a six-turbo 903ci Cummins V-8.