3" Downpipe Exhaust 2015-2020 Ford F150 Pickup SPELAB Type： 3" Stainless Steel Downpipe : If additional purchase is available, more than 50 in stock. Vehicle fitment: Fits All 2015-2020 Ford F-150 Pickup What does a downpipe do? The downpipe on your turbocharged vehicle is directing the exhaust gases out of the turbine housing into the exhaust system. An aftermarket downpipe will typically be larger in diameter and either uses a high-flowing catalytic converter or remove the catalytic converter altogether. By removing the factory downpipe and replacing it with a high flowing unit you are allowing the turbo to more efficiently move gases away from the turbine which creates more power. Since the factory restrictions are now gone you can increase the boost on the vehicle as the factory downpipe is a choking point for performance.