When subjected to the 1700+F gas temps seen in these turbo engines under load, the cast iron material has a tendency to warp, crack and or break studs, potentially damaging your cylinder heads. For years 304 stainless steel has been a go-to material for sturdy, long lasting turbo manifolds and other motorsport exhaust components. But EcoBoost 3.5L owners push their engines hard and demand extreme reliabilty under grueling conditions, failure is not an option. Increased manifold outlet from 30mm (1.18”) to 34.5mm (1.36”) to match the size of the entry to the turbine housing (also 34.5 mm). This small change translates into a 32% increase in outlet area. All this will result in reduced backpressure and increased turbocharger efficiency
