Why bother with the upgrade?
The MX-5’s oil pump gears are known to be a weak point in the motor. Every time the engine is brought up past its stock redline, or past its factory power level you are pushing a pump that was designed to the lowest denominator using powdered metal casting technology. This process of casting produces parts that are between 5%-10% the strength of 4340 billets. On top of that cast components tend to crack, not bend, so when the oil pump assembly does self destruct its likely to be a catastrophic and sudden failure that can ruin Carrillo rods, JE pistons, and high performance camshafts in a matter of seconds.
If you do take the risk of assembling your high performance engine with a powdered metal stock oil pump it still takes sophisticated measuring equipment to ensure the replacement pump you ordered is in specification for your housing. Measurements down to .0005 and surface roughness are both measured very accurately using the Boundary Engineering inspection process. The tools do this step alone are worth thousands, and with this purchase its already taken care of for you by highly qualified machinists.
This product takes all the guess work out of assembling your motor. Purchase, bolt on, drive, and never worry that your engine’s next red-line visit could send 8000 RPM components into a steel on steel grinding match.
The street/strip is the upgrade to the 91.5-00 and the Race is the upgrade to the 01-05 VVT motor.
All three pumps are interchangeable. The advantage to the higher flow pumps comes about through more mid range bearing support because you will get more oil pressure sooner in the RPM band.For most cars we recommend the street/strip pump. We also recommend 2 shims in the relief valve which raises the relief valve pressure by 10-14PSI. This helps the bearings at the high RPM range gain more support.