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TracTuff RBB/ RBC Water Bypass Adapter Filler Neck

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Over the years I have been challenged with making several upper water necks, filler necks, fill pots, and swirl pots that fit with crazy sidewinder turbo manifolds and huge turbos! Some of these jobs have presented such unrealistic situations that it has left the job near impossible to complete with the budget being offered. Enter the Water Bypass Filler Neck!! A spin on our VERY popular water bypass adapter for the K20Z3/ K24A2 that allows RAA, RBC, RBB, and RSP cylinder head owners to not only run the more popular aftermarket intake manifold options that were designed for the earlier PRB/ PRC flange BUT also adds cooling system fill point! Eliminating the conflict of a filler being placed in close proximity to the turbo inlet and complicating plumbing.

In addition to the awesome feature of being able to fill your cooling system from the highest point... the water bypass adapter is known for reducing intake manifold temps by eliminating the heat transfer/ heat soak associated with hot coolant running through the manifold. By modifying the manifolds flange (cutting off coolant portion) and running our adapter the coolant is kept away from the manifold completely, just like what you would find on the earlier PRB/ PRC heads, so NOW your Hondata IM gasket will really work!! We've seen drops as much as 18°!! Not to mention, the additional benefit of no longer having to drain the coolant when removing the intake manifold for maintenance or swaps... makes things a real SNAP!

NOTE: Made to Order - Contact for ETA - If you are interested in a specific design that varies from this, please email us at or if you have questions related to the configuration or options. The cap bung has a 1/16" NPT port for connection to an overflow and uses early model Honda radiator caps; such as an 88'-91' Civic/ CRX or 90'-93' Integra.