Stage IV CNC Gasket Matched and Ported Manifold

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Product Overview

JMTC S4 Ported Manifold 


What good is a high flow ported head if the biggest restriction is in the exhaust manifold? The Mini manifolds and even a JCW manifold were only designed for air flow around 250hp. Once you add a big turbo, intake upgrades, and a ported big valve head the exhaust manifold will soon become the biggest restriction in the system.  The exhaust manifold port diameters are just to small for the engine to reach its full potential at the top-end.  So we developed our Stage IV hand ported manifold, extreme CNC expanded at the turbo, and gaseket matched to the head. 

JMTC’s Stage IV CNC port matched (exhaust side) and opened up on (turbo side will need to be matched by customer or JMTC see notes) is the only manifold on the market that will allow the engine to flow to its full potential.  The work we do to the Stage IV manifold will out flow the JCW manifold while retain the twin scroll port for quick spooling of the turbo.  this way you get a great top-end and don't loose any torque as the turbo is spooling up like you will on a log manifold.

Stage IV

  • CNC extreme port expanded on the turbo side
  • turbo outlet flange expanded +10cm or ~1/2"
  • Port are gasket matched to the head
  • Port matched (if you get our S4 turbine housing upgrade) 
  • Airflow path from port 3 is open and expanded 
  • The combined port 2/3 is 3 times the size of the JCW manifold.




JMTC inspects and repairs all refurbished parts so they will operate properly, however refurbished means this part has been previously used and may have defects.  We modify, weld, and machine this product so no refunds for intentional changes or CNC tooling marks.

Pre-shipped manifold core is $150 the money will be refunded once a usable core is return to us. 

Damaged or cracked core and pre-shipped manifolds will be repaired at no charge or deduction from the core. 

The turbine housing will need to be machined to the exhaust manifold however only the JMTC housings on the GTD and S45 post 2018 can be machined to match this manifold.  If you have a Non JMTC turbo, JM40, a turbo that was made prior to 2018 it will need to be sent to us for modifications.  Most likely it will need a new housing and machining, contact JMTC for additional info. 





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