Catch can tech, how to, theories, and install on S2000

A catch can is a crucial addition to your car’s engine, especially if you’re pushing for higher performance. It works to alleviate excess crank case pressure that builds up in the engine due to blow by – the small amount of air that escapes past the piston rings during the compression stroke. While all vehicles experience blow by, the standard PCV (positive crankcase ventilation) system that comes with cars from the factory might not suffice for high-performance engines or those running at high RPMs. The issue with the factory PCV setup is that it redirects the gases/vapors from blow by back into the engine’s intake manifold, where they are burned up during the combustion cycle and expelled as exhaust. While this method is environmentally friendly, it can have detrimental effects on the engine. Upgrading to a catch can setup is essential for effectively managing blow by and preserving engine performance.

  1. Crank case vapors are filled with oil, spent fuel, and other gasses that will actually lower the octane of the gas you are feeding to the engine, thus lowering over all power, or in extreme cases can cause knock/detonation which can be detrimental to a high horsepower/performance engine.
  2. Will cause your intake manifold, throttle body, valves, and fuel injectors (if you have port injection) to get black tar caked all over the insides, and building up deposits on the top of the valves. Which of course will rob your car of power.
  3. Can cause excess oil to flow out of the PCV and get burned in the combustion chamber (causing your car to smoke). The S2000 is notorious for this under hard right turns.

Catch cans play a crucial role in vehicle performance. Opinions on the right catch can vary, but this article aims to provide clarity on their function, different setups, necessity, and installation, using Patrick’s s2000 as an example.

Starting off, there are essentially two main types of setups you might encounter. Without delving into systems that utilize electric pumps to extract the pressure or systems that tap into the exhaust and leverage a Venturi effect to “suck” the gases out, which are more complex to set up and not commonly utilized by the average enthusiast. Most people will opt for one of the following two options.

  1. One that is vented to atmosphere (VTA)
  2. One that is recirculated

A vented system features a filter on top of the can and utilizes crank case pressure and atmospheric pressure to expel gases. Vented setups often employ larger diameter hoses, or even multiple hoses, to minimize restrictions during gas evacuation. The smoother the gas escape, the more efficient the process.

For a recirculated setup, it utilizes the intake system’s vacuum to expel the gases. This mirrors the setup present in your car from the factory, with the addition of a catch can placed in line between the valve cover and the intake manifold. The vacuum effectively pulls the air out, allowing for the use of smaller lines, as seen in OEM PCV setups with their smaller hoses.

I firmly believe that the majority of people will opt for the vented method. This approach appears to be the most effective because it prevents the recirculation of contaminated air back into the engine, thereby potentially reducing engine performance. Additionally, engines operating at WOT (wide open throttle) generate little to no vacuum, meaning that even if recirculation were to occur, there would be insufficient vacuum to extract the vapors. Some individuals insist on mounting the can above the engine to prevent it from filling up too quickly. However, I think this theory has too many variables, and it is best to choose the method that works most effectively for you.

To correctly establish a vented system, all connections from PCV or valve cover venting to the intake tube or intake manifold must be severed, and the PCV should be completely removed. This ensures that no “contaminated” air is drawn into the engine, and only fresh air is received. While some companies offer high-quality filters and baffle systems in their catch cans to reduce the recirculation of “contaminated” air into the intake system, I believe that the optimal approach is to allow it to vent to the atmosphere.

There are various reasons for using different types of catch can setups. Whether your vehicle is turbocharged, supercharged, equipped with NOS, or simply known for excessive blow by, the choice of setup is entirely yours. It’s important to remember that the primary goal of a catch can is to alleviate the built-up crankcase pressure. Excessive crankcase pressure under extreme conditions can lead to seal blowouts, loss of engine power, and potential engine damage. High-performance cars, race cars, and track cars often utilize catch can setups because they push the engine to operate under extremely demanding conditions for which it wasn’t originally designed. Prolonged high revving and intense boost pressure, particularly on stock engines not designed for such conditions (such as when adding a turbo to a naturally aspirated stock engine), can significantly strain the engine.

I must emphasize that considering a catch can for your car solely for aesthetic reasons is unwise. An effective catch can setup will require a significant investment, and without it, regular street driving will not benefit from it. In fact, it may lead to unfavorable perceptions and ridicule from those knowledgeable in racing. Additionally, it is crucial to invest in an engineered catch can with baffles and filters, rather than opting for the cheapest available option on Amazon. For a recirculated setup, inexpensive catch cans may allow oil vapors to enter the intake system, defeating the purpose of installing a catch can. Therefore, it is essential to prioritize the installation of high-quality parts.

Now, let’s walk through the installation process on Patrick’s S2000.

He opted for a Radium dual-can setup with a breather setup that vents to the atmosphere. The setup includes -10 push lock fittings and push lock hose. On the S2000 AP2, the PCV is located on the valve cover and is threaded, allowing for a straightforward installation of a -10 bung. This configuration is remarkably easy to set up. Unlike most B/D series Hondas, the S2000 lacks the black box on the back of the block that the PCV comes out of, making the installation of a catch can setup for S2000s very straightforward.

You can clearly observe the -10 blue bung threaded into the old PCV hole.

Before the installation of the catch cans, this is what the car looked like. It’s important to note that the motor had just been swapped in, and the “catch can” setup in the picture was temporary, serving to catch any overflow during the drive to my house.

So start off by removing the intake.

Rigby thrives on being right in the heart of the action, reveling in every moment of it.

“This is the stunning setup of the Radium 2. It’s an incredible piece with remarkable quality and craftsmanship!”

Next, it’s crucial to thoroughly test fit all the lines and ensure there is ample clearance for the intake once it’s reinstalled. As depicted in the image above, everything is currently being test fitted without any components being bolted down.

Here is Patrick measuring out the hose length before cutting.

Rigby once again trying to be in the action

We clearly indicated the precise locations where we desired the holes to be drilled in order to mount the bracket.

Here is what it looks like with both holes drilled.

Next, we employed a Nutsert tool to effortlessly add threads, allowing us to simply use a bolt to secure the bracket without the need for a nut. This tool functions in a manner similar to a rivet tool – by threading a nutsert onto it, inserting it into the hole, and then applying pressure, much like you would with a rivet tool.

Here is what the hole looks like with the Nutsert installed. As you can see, our once thread-less hole now has threads. This tool is incredibly useful.

Here is the bracket and catch cans all securely bolted in.

Here it is with all the lines installed. As you can see, the original PCV has been removed and replaced with a -10 bung threaded in. Then a fitting was run off that threaded bung to one catch can, eliminating the PCV from the motor. Now, it’s just a line to a catch can with a breather. Additionally, the other valve cover vent that originally went to the intake is now routed to the other catch can. Therefore, two -10 lines are run to two separate catch cans, effectively providing all the crankcase ventilation.

As you can observe in the image, there is a conspicuous green plug on the intake manifold, previously housing the hose for the OEM PCV. This component has been eliminated, effectively preventing “contaminated” air from entering the engine.

Here it is all reassembled, with the capped nipple on the intake. (Note: the radiator cap is off only for re-bleeding the coolant system and is unrelated to this.)

Our beloved Rigby adores spending time with us in the garage, unfazed by the scorching heat outside!

A couple of things to note from this install: the catch cans were mounted at a slight angle, affecting the accuracy of the dipsticks that come with the radium cans. While this wasn’t an issue for Patrick due to his regular car maintenance, those looking for a “set it and forget it” solution should ensure they are mounted level. Additionally, it’s worth mentioning that radium offers an S2000 kit, but installing it would require removing the cruise control, which Patrick preferred to keep. I did tease him about the need for cruise control in a race car, though!

Finally, if you have installed a catch can on your car by welding bungs to the valve cover but still have the PCV connected to the intake manifold or tube, you are only halfway there. While you are venting extra crankcase pressure, you are still allowing “contaminated” air to enter the engine through the OEM PCV. It is best to ensure that nothing other than fresh air is sucked into the intake system.

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