Boundary Engineering Billet Oil Pumps

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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.

 Which pump should you choose?

Street Pump (Chromoly Pump - NON VVT)

A good all around choice for 90% of the non VVT builds we see.  If you're looking to produce higher power levels and increase your limiter this is a safe move for you.  With 4340 billet gears you won't be let down. 

  • Custom machined chromoly oil pump gears fitted uniquely for each housing
  • Housings are fully de-burred to reduce turbulence and increase flow
  • Blueprinting verification system using signed and dated sheets stating your particular pumps clearances and processes.
  • Cleaned using ultrasonic, air blast, and visual inspection technique
  • Assembled with Teflon® impregnated grease
  • Sealed in air tight heavy mil bags to prevent foreign contamination
  • Relief Valve dis-assembly, blueprinting, and re-assembly

Street/Strip (High Flow Pump - VVT Compatible) 

The assembly starts off with a set of oversize Boundary Engineering oil pump gears. Then the housing is machined to increase flow, and ensure the perfect home for the oil pump gears. The gears fitted are 4140 billets and the housings are machined in state of the art Matsura mills. For this reason, these assemblies are a step above the billet oil pump gears or other "high flow part" offerings. This is a true high flow oil pump, and we have the proof.


Comparion of same engine before and after Oil Pump Installation
Comparison of same engine before and after Oil Pump Installation

This graph shows a 400whp Miata motor powering down Button Willow with the stock oil pump assembly, which by the way, did explode on the driver in one of the straight stretches. The other data plotted is a new high flow oil pump assembly tested at Willow Springs road course. The maximum oil temperature difference between any 2 matching points is just 3*C with many points being less than a half of degree Celsius separated. The same weight and brand of oil were used in each run. This is the same engine and it was rebuilt to the original engines specs, same turbo, same everything, but with the new high flow oil pump equipped. The differences were as much as 18 PSI! The new billet oil pump gear not only protects your engine from exploding stock oil pumps, but also provides up to 25% extra pressure to keep your block together.

Assembly is ready to bolt on with new:

  • Larger higher flow chromoly billet oil pump gears
  • Compatible with the LARGE NOSE 1.6L only 
  • Machined oil pump housing complete with hardware
  • High Pressure Oil Pump Seal (o-ring)
  • Crank Seal

8 Reviews

  • 4
    Boundary Oil Pump

    Posted by Michael Estes on Jun 20th 2019

    Unfortunately, the unit I received had a leaky front main seal (there is a whole thread about the bad seals Boundary was using on the Miata Turbo forums - I just dropped my rebuilt engine in about 200 miles ago, and had a pretty serious oil leak show up. I pulled the front of the engine back apart, and there was a lot of oil seeping between the seal lip and the crankshaft. I replaced it with a nice Timken seal, so with any luck this one will keep the oil in. This is not something one should have to expect to do with a $300 oil pump though. Do yourself a favor and inspect it before you install, if the seal your unit came with says CXLK on it, just replace it before ever installing it.

  • 5
    Good looking pump

    Posted by Daryl on Oct 1st 2018

    Very good quality item and well made. Haven't tested yet as engine is being rebuilt currently

  • 5
    Best price online, quality piece

    Posted by Jacob Ortega on Aug 26th 2018

    Highly recommend this for a turbo setup pushing a good bit of power. Came in speedy and price was great. Install was a sinch.

  • 5
    Boundary Engineering Billet Oil pump

    Posted by Ivan Veldkamp on Apr 28th 2018

    The oil pump looks like it's from great quality and was packaged really good. It had al the documents nicely packet inside and the pump itself is sealed so it can't become dirty. Lets put it on my engine to keep it safe!

  • 4

    Posted by Ryan on Mar 19th 2018

    It's a quality looking part, only issue I have with it is that the package was already opened and not sealed as it should have been.

    Fab9 Response: Hey Ryan, these are opened because the shims are configured here in-house per order. We are authorized to shim these pumps to make sure our customers get what they need, as quickly as possible. It's completely normal that the package was opened. We also write the shim number on the included spec sheet so it can be documented with your build.


  • 5
    super great product, customer service!

    Posted by Brett on May 27th 2017

    Cannot thank the fab9 guys enough, very helpful and quick to respond with questions about the different pumps. Fast shipping, solid product. Great packaging, cool stickers and certificate of authenticity. 12/10 recommend!!

  • 5
    the nicest bit on my car

    Posted by james annis on Dec 19th 2016

    When i opened up the package containing this engine critical part i was staring at the gate of fort knox. This was impeccably packaged, comes with the warranty and article inspection report in an envelope sealed with ribbon and wax stamp. The pump itself was sealed in an airtight bag.

    Very happy with packaging, fit, function and turn around.

  • 5
    great product

    Posted by Kris on Apr 26th 2016

    Packaging, fitment and performance all better then anything else on the market