1993 Mazda RX-7 Turbo Manifold T4 Divided 4Bolt HKS 40mm WG Stainless Steel. Upgrade your 1993 Mazda RX-7(13B) with this high-quality OBX Turbo Manifold. Made from semi-polished stainless steel, this manifold features T4 divided flange with 4 bolt HKS 40mm WG for optimal performance and durability.