Boundary Oil Pump - 91.5 - 05 Miata

Boundary oil pumps for the BP engine in the 1991.5 to 2005 Miata start with a housing that is fully torn down and inspected, then built with Boundary's billet gear set.

Every pump is taken completely apart, ultrasonically cleaned, air blasted, inspected and deburred by hand. It's built with Boundary's mirror finished gear set, and the stock fasteners are replaced with stainless Torx head bolts that are torqued to spec and secured with Loctite. Anaerobic sealant goes on the critical areas to help the pump prime faster and reduce aeration, and assembly lube goes on every critical surface so oil flows quickly on the first start. Each pump is blueprinted and comes with a specification sheet.

The Stage 2 pump has a deeper pocket machined into the housing to fit larger gears. That increases flow, mid range oil pressure and gear strength, and makes it compatible with VVT engines. The Stage 2 pump is also shimmed, raising maximum warm oil pressure from 60 PSI to 72 PSI. This is the pump that I use and recommend for almost every build.

Stage 1 fits the 1991.5 to 2000 Miata with the long nose crank and is not recommended for VVT engines. Stage 2 fits the 1991.5 to 2005 Miata. Both can be ordered with or without the shim pack.