Bought the BD three piece manifold to replace t...
Great as a stock replacement, our exhaust manifolds were designed with expansion joints and heavy webbing to prevent cracking. The exhaust runner design maintains exhaust velocity to drive the turbine wheel. Runner size does not go beyond the size of the exhaust ports on the head because when the runners are larger, the velocity to drive the turbo is lost due to the expansion and temperature in the exhaust manifold reduces the turbine drive pressure needed for turbocharger response.
Product Warranty 36-Month Part