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Upgrade your failure-prone PCV breather hose with the high-performance, 034Motorsport Catch Can Kit, engineered for enhanced durability to capture crankcase oil deposits before entering your intake tract.
The PCV, or Positive Crankcase Ventilation system, on the EA839 is located on bank 2 of the engine (The right side of the engine). It is designed to ventilate the engine's positive crankcase pressure through a breather hose into the intake tract or charge air system. The 034Motorsport Catch Can was engineered to improve upon the factory PCV system, implementing a baffled Billet Aluminum Catch Can to trap crankcase oil deposits before entering your intake tract. The Catch Can Kit utilizes a re-engineered breather hose that plays an integral role in this ventilation system.
How Does the PCV System Operate? The Positive Crankcase Ventilation System, or PCV for short, works to remove excess pressure from the crankcase system and relies on vacuum from the engine’s intake system to operate properly. This system operates with two components, an Air Oil Separator and a Breather Hose.
In the EA839, crankcase pressure is generated by the engine rotating assembly moving under normal operation, and can contain oil in the form of liquid & vapor, water vapor from condensation, and blow-by gases. The Air Oil Separator acts as a collection chamber for this crankcase pressure and oil, separating some, but not all of the oil and water vapor, allowing the oil to drain back into the engine oil pan. The crankcase pressure not caught in this chamber is evacuated through the breather hose to be ingested by the engine.
At idle or cruising while not in boost, the engine’s charge air system operates under vacuum, drawing air in continuously. During this state, the breather hose utilizes this vacuum to release crankcase pressure into the charge air system through the connection just after the throttle body.
However, when the vehicle is under boost (during acceleration), this connection becomes pressurized, meaning it can no longer provide a vacuum source for crankcase ventilation. When this happens, a check valve in the breather hose closes off this connection, preventing boost pressure from entering the crankcase. At this point, the breather hose is able to draw vacuum from the turbo inlet connection, as this creates vacuum through a siphoning effect as the turbocharger draws air in through the intake.
Whether you are sitting at a stoplight or romping on a backroad, a properly operating PCV system is crucial for maintaining the engine’s performance and preventing harmful pressure buildup.
The check valves within the factory breather hose are an integral component of ensuring correct operation. However, since these check valves deal with the high temperatures of an engine bay and the transition between vacuum and boost pressure, they are susceptible to premature failure. When they fail, excess pressure can enter the crankcase, causing it to operate under conditions it was not designed for. In fact it’s likely these are the same as what Audi uses on naturally aspirated engines, which makes them not up to the task of dealing with pressures associated with turbocharged engines.
As the crankcase of the engine is not designed to operate under pressure, it typically will find the path of least resistance to release this excess pressure. The seals and components inside your engine, which are designed to operate under vacuum, aren’t built to handle this excess pressure. In some cases, the path of least resistance is unfortunately the oil cap, which can loosen and expel hot oil into the engine bay, potentially causing a fire.
Audi issued a TSB (Technical Service Bulletin) concerning this failure of the PCV Breather Hose as of 2020, though in our testing 034Motorsport has concluded that even the newest variant of breather hose is susceptible to failure.
Some other solutions on the market neglect the importance of maintaining adequate vacuum pressure from the charge air system and intake tract to ensure proper operation of the PCV system. Because the PCV system relies on these two separate vacuum sources under normal operation, removing one would prevent the crankcase ventilation system from functioning properly.
When these solutions remove the upper intake manifold as a vacuum source, it disrupts the PCV system’s ability to vent crankcase pressure at idle or in a cruising state while not in boost. Because the crankcase no longer has sufficient vacuum pressure, seals that are designed to operate with this vacuum pressure can fail prematurely. This lack of vacuum pressure can also lead to the potential of pressurization of the crankcase system and engine damage.
Additionally, many aftermarket solutions have check valves that do not provide sufficient flow to accommodate the boost levels of Stage 3 equipped vehicles. These check valves are too small and this inefficiency can cause restrictions, resulting in reduced flow from the crankcase, causing crankcase pressure to build up.
During the development of the 034Motorsport Stage 3 Dynamic+ tuning suite, the development B9 Audi S4 experienced an unfortunate OEM PCV breather hose failure. This failure caused oil to be expelled through the oil cap and onto the hot turbocharger, immediately causing an engine oil fire. This failure was documented in our video Ashes to Asphalt, documenting the extent of the damage and how 034Motorsport was able to make the most out of the situation. Because of this failure, it made engineering a proper solution that was able to withstand the harsh engine bay temperatures and elevated boost levels of utmost priority for 034Motorsport Engineers.
12 Months
All products sold by Eurosport Performance are warrantied against manufacturing defects according to the manufacturer's warranty policy*. Warranty does not cover abuse, misuse, damages caused from improper manipulation, normal wear and tear, improper installation, or damages resulting from racing. Warranties only apply to the original owner. If a product is found defective, the customer will receive, at the discretion of Eurosport Performance, a replacement part at no extra cost.
* Conditions may apply. Please visit our Refund Policy or contact us at info@es-performance.com
