What engines need catch cans?

Catch cans, also known as oil catch cans, are essential for certain types of engines to prevent oil and other contaminants from entering the intake system. These devices are particularly important for turbocharged and direct-injection engines, as they help to maintain engine performance and longevity.

Engines That Require Catch Cans

The engines that typically need catch cans are those that are prone to oil and fuel buildup in the intake system, which can lead to various issues. These include:

• Turbocharged engines: Turbochargers create positive crankcase pressure, which can push oil and other contaminants into the intake system. A catch can helps to capture and contain these substances, preventing them from entering the engine.


• Direct-injection engines: In direct-injection engines, fuel is sprayed directly into the cylinders, which can cause carbon buildup on the intake valves. A catch can helps to collect and remove this buildup, maintaining engine efficiency.


• High-performance engines: Engines with high-performance modifications, such as increased horsepower or boost levels, are more susceptible to oil and fuel contamination in the intake system. A catch can helps to mitigate these issues.

By installing a catch can, you can help to prevent these problems and ensure your engine runs smoothly and efficiently.

Benefits of Using a Catch Can

Installing a catch can on your engine can provide several benefits, including:

• Improved engine performance: By removing oil and fuel contaminants from the intake system, a catch can can help to maintain optimal engine performance and efficiency.


• Extended engine life: Preventing the buildup of oil and carbon deposits in the intake system can help to reduce wear and tear on engine components, extending the overall lifespan of the engine.


• Reduced emissions: Catch cans can help to reduce the amount of oil and fuel vapors that are released into the atmosphere, contributing to lower emissions and a more environmentally-friendly vehicle.


• Easier maintenance: The catch can can be easily inspected and emptied, making it a simple and effective way to maintain the health of your engine.

Overall, catch cans are a valuable addition to engines that are prone to oil and fuel contamination, helping to ensure optimal performance and longevity.

Do turbo engines need a catch can?

In turbocharged applications, you will need to choose a pressure-sealed catch can to prevent boost-leak.

Why are oil catch cans illegal?

Oil catch cans can be illegal because they modify a vehicle's positive crankcase ventilation (PCV) system, which is part of the vehicle's emissions control system. Altering the PCV system is often illegal in states with strict emissions standards, such as California, as it can interfere with the reintroduction of crankcase fumes into the engine for proper combustion and emission control. Some catch cans that vent to the atmosphere are explicitly illegal because they release pollutants, while others may be non-compliant if they aren't installed correctly or don't meet local regulations.
 
This video explains why oil catch cans can be illegal in some areas and when they are compliant: 1mBig Truck Lovers YouTube · Aug 27, 2025
Reasons why oil catch cans can be illegal

• Tampering with emissions systems: Installing an oil catch can is considered a modification of the factory emissions system. The PCV system is designed to route crankcase fumes back into the engine to be burned, which reduces air pollution. 
• Venting to atmosphere: Many catch cans have an air filter that vents to the atmosphere, releasing pollutants and making them illegal in many areas with strict emissions laws. 
• Disrupting engine function: Some catch cans can alter the flow of air and pressure in the engine, potentially causing the engine to run less efficiently. 
• Visual inspection: During an emissions test, a visual inspection may identify the catch can as a non-compliant modification, leading to a failed inspection. 

When catch cans might be legal

• Closed-loop systems: Some catch cans are designed to be compliant because they maintain a closed-loop system by venting clean air back into the intake, but this requires specific, non-venting designs. 
• Local regulations: The legality varies greatly by location. Some states may allow them, while others, like California, have much stricter rules. 
• CARB-compliant models: If a model is specifically certified by the California Air Resources Board (CARB) and is installed correctly, it may be legal to use in California. 

You can watch this video to learn more about the effects of oil catch cans: 1mAuto Expert John CadoganYouTube · Jul 18, 2018

What engines need an oil catch can?

Engines that are turbocharged, direct injected, or both may benefit from an oil catch can. Turbocharged engines generate more blowby, or leakage, which in turn increases the amount of pressure that needs to be evacuated from the crankcase.

Are catch cans good for your engine?

Oil catch cans help maintain optimal engine performance by keeping the intake system clean. Improved Airflow: The presence of oil vapor and contaminants in the intake system can disrupt the airflow and air-to-fuel ratio, leading to less efficient combustion.