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TracTuff K24Z Water Bypass Adapter


The OG water bypass adapter. Imitated but not duplicated and still the best looking, best fitting (leak free!), and now the least expensive!

The water bypass adapter allows K24Z (R40 style cylinder head) owners to run the more popular aftermarket intake manifold options that were designed for the earlier PRB/ PRC k series cylinder head flange. PRB/ PRC style manifolds do not cover the right most portion of the intake manifolds flange, so the coolant bypass and EGR passages are left exposed. The 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 a PRB/ PRC style manifold... there are plenty of benefits that make this product a smart purchase! Benefits such as a reduction in intake manifold temps by eliminating the heat transfer associated with hot coolant running through the manifold. By simply modifying the manifolds flange (cutting off coolant portion) and running this adapter, the coolant is kept away from the manifold completely, just like what you would find on the earlier PRB/ PRC heads. I've personally seen drops in temp as much as 18°!! The other notable benefit is my personal favorite, NO LONGER HAVING TO DRAIN COOLANT when removing the intake manifold for maintenance or swaps! Which means, NO UNNECESSARY BLEEDING!

NOTE: The sensor port selection is OPTIONAL. If you don't have/ need a sensor... don't select it. I only offer 1/8" NPT or 1/8" BSPT (Honda Single Prong Sensor).

Installation Guide


The manifold shown is JUST AN EXAMPLE... I'm not going to re shoot instructions for every manifold out there. Understand that as long as the aftermarket manifold you own has the same shape as the OEM PRB/ PRC manifolds (like the one shown) or an aftermarket company did a good job of holding to Honda's tolerance, my adapter will fit perfectly! This was the first product on the market and its been flawless since 2012.

UPDATE: Nowhere in this write-up do I mention OR recommend the use of Hondabond or an RTV sealant. This is NOT an oversight or accident. I don't mention it or recommend it BECAUSE IT DOES NOT NEED IT. The o-ring seals directly against the cylinder head. DO NOT INSTALL OVER ANY TYPE OF GASKET!!

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.