Tag Archives: RB20DET Intake Manifold Modification


Nissan Skyline HR32 GTS-4 AWD RB20DETĀ  Intake Manifold Modification

Complete Nissan Skyline RB20DET INTAKE MANIFOLD Rebuild by Greg!Ā 

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Nissan Skyline GTS4 AWDĀ Ā RB20DET – Single Turbo 2Ltr
Complete RB20 INTAKE MANIFOLD Rebuild!
RB20 Custom Intake Manifold

Nissan RB20 Custom Intake Manifold

This is how the intake looked afterĀ fitting the Nissan Skyline GT-R HR33 FMIC -( Front MountĀ Inter-Cooler)Ā  to the front of the Skyline GTs-4.Ā Ā Obviously the air inlet tract isĀ traversing the front of the engine over toĀ the original position of the side mountedĀ inter-cooler piping, then progressing alongĀ the original cast pipe with the BYPASSĀ ValveĀ (NOT BLOW OFF VALVE – ITS AN AUTO!!) to the original throttle body. The BYPASS Valve assy and tube was used to complete the factory look and function in final execution of the system.

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This solution is not the optimum becauseĀ of HEAT SOAK and the distance for the air to travel, creatingĀ lag.

The solution as it occurred to me was the manifold entry point and throttle body should be at the front of the manifold for efficient flow from the incoming inter-cooler piping. With the basic design in my head I worked out very roughly with foam and tube where the best location would be. There were many things to take into consideration in this complicated modification. Most of all efficient and safe operation with a factory look and feel determined the final outcome, including the crinkle black finish. This was done by the coating company that suggested it instead of polishing the aluminium.
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Here you can see the original IntakeĀ Manifold has been cut in half to remove theĀ original throttle body mounting and theĀ Coolant Bleed Chamber. I mocked up theĀ intended plenum and the front curvedĀ extension neck to mount the originalĀ throttle body back on to for ease ofĀ construction. I also wanted to reuse theĀ original TB for continued integration intoĀ the standard Nissan ECU.
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So considering that the best idea would beĀ to shorten the inlet to the end of theĀ front of the original manifold, I setĀ about making a mock up of the shape IĀ considered that would be the best in termsĀ of flow and capacity for a decentĀ reservoir of pressurised air ready to beĀ used on the next intake cycle.
Considering that the Nissan RB20DET is not exactly aĀ low RPM torque monster, I had dividersĀ made up for each intake duct to lengthenĀ the runners a few inches as the largerĀ capacity plenum allowed.
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Hopefully theĀ dividers would create a bit more torque downĀ under 3000RPM where the Nissan RB20DET 2.0ltr 6 Cylinder Engine isĀ definitely lacking before getting into boost

Finished Job Xmas 2005Ā Notice Aluminium and Glass Bowl at rear of Manifold with pressure relief valve at top. This is the alternative engine coolant system that allows bleed off of any air in the coolant system that can reduce its effectiveness.

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