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TracTuff RBB/ RBC Water Bypass Adapter


The included 90° water bypass hose elbow will not be zinc plated as shown. I am waiting for a large order of brass fittings to show up and then they go to plating. I'm looking at 3-4 weeks before I have plated fittings on hand.

Imitated but not duplicated! The TracTuff Water Bypass Adapter was the first product on the market and is still the best fitting and problem free (no leaks) solution available.

I came up with this product in 2008 so K20Z3 engine owners could use all the intake manifolds that were made for the previous generation cylinder head; being the Z3's RBC cylinder head and all those like it (RAA, RBB, and RSP) have a water passage incorporated into the intake manifold that is not present in the popular aftermarket options that were designed for the earlier PRB/ PRC cylinder head. The PRB/ PRC style manifolds do not cover the right most portion of the intake manifolds flange, leaving both the coolant bypass and EGR passages exposed. My water bypass adapter allows you to make the water passage connection as well as cover the unused EGR passage.

Even if you don't plan on running an aftermarket intake manifold... there are two benefits that make this product a smart purchase!

  1.  A reduction in intake manifold temps by eliminating the heat transfer associated with hot coolant warming the manifold.
  2. No longer needing to drain and bleed the cooling system when removing the intake manifold for maintenance or swaps.

NOTE: The sensor port is OPTIONAL. If you don't have or need a sensor... don't select it. I only offer 1/8" NPT or 1/8" BSPT (Honda Single Prong Sensor). If you are interested in deleting the water bypass hose and its function, please check out my dedicated Water Bypass Block-Off.

Please understand that the intake manifold shown is JUST AN EXAMPLE. Please also understand that my water bypass adapter was designed and machined for a perfect fit when using the Genuine Honda PRB/ PRC manifold shown. I cannot control what aftermarket intake manifold companies do with their shape. If the water bypass adapter does not fit properly, the manifold casting is to blame, and you will need to make a choice on which of the two products will be modified. I recommend you remove material from the manifold so as to not make a mistake that will move the o-ring position and cause a leak. 

Also,  nowhere in this write-up do I mention the use of OR recommend Hondabond or any RTV sealant. This is NOT an oversight or accident. It is NOT needed. The o-ring seals directly against the cylinder head. Do NOT install the water bypass adapter on top of any type of gasket!!

The water bypass adapter does not support EGR. By purchasing this product, it is assumed that you either don't have an engine with a complete EGR system or you have deleted it by using a water neck that renders the passage useless. A useless passage does not require being sealed (which is why I did not incorporate a seal).

Installation Guide


Start by installing the o-ring into the recess on the adapter’s backside and set the adapter aside. If you need assistance with keeping the o-ring in place, use a small dap of grease or sealant.

Grab the stainless steel link and the 35mm Genuine Honda flanged bolt. Install the bolt into the unthreaded hole in the link.



Install the bolt and stainless link into the right-most intake manifold flange bolt hole. Tighten lightly with the link facing upward.

Grab the shorter 35mm Genuine Honda flange bolt and adapter and install the bolt into the lower bolt hole.


Take the bolt and adapter and install it over the exposed water & EGR ports. Thread the bolt into the cylinder head until it is hand tight. Do NOT install the adapter over a gasket of any type!

Grab the stainless steel set screw and thread it into the stainless link. The pointed set screw will tighten into the hole well but in some extreme cases it may be a good idea to use some medium grade Loctite.


Swing the stainless link and set screw down until it lines up with the pilot hole of your choice.

Tighten the 8mm intake manifold and Water Bypass bolts to 18 lb. ft. of torque and tighten the set screw until you have sufficient crush on the adapters o-ring. The thin 8mm jamb nut is not shown here but it would either go on the exposed threads of the set screw (face of the link) if there were enough threads OR in between the link and the bypass adapter (shown) and tightened to lock the set screw in place. Congratulations! You're done.