Understanding the Role of a Catch Can

In modern turbocharged engines, the Positive Crankcase Ventilation (PCV) system is designed to recirculate blow-by gases—a mixture of combustion byproducts, oil vapors, and moisture—back into the intake manifold. While this reduces emissions and meets regulatory standards, it also introduces oil-laden vapors directly into the intake tract. Over time, these deposits can coat intercooler pipes, throttle bodies, intake valves, and the compressor wheel of the turbocharger. A catch can, such as the popular Mishimoto catch can, intercepts these vapors before they reach the intake, separating and collecting the oil while allowing the cleaned air to continue into the combustion chamber. By doing so, it prevents the gradual accumulation of carbon and varnish that can degrade turbocharger performance and longevity.

The direct benefit to a turbocharger is twofold: less contamination on the compressor wheel reduces aerodynamic inefficiency, and cleaner intake air helps maintain proper air-fuel ratios. This is especially critical in direct-injection engines where intake valve cleaning by fuel is absent. For forced-induction setups, the turbo relies on clean, consistent airflow; even minor deposits can cause surge, reduced spool speed, or increased exhaust gas temperatures. A catch can is not a power adder, but it is a preservative measure that helps the turbocharger operate closer to its design parameters over thousands of miles.

How Oil Vapors Affect Turbocharger Longevity

Turbochargers spin at extremely high speeds—often exceeding 150,000 RPM under full load. At these speeds, even microscopic particles or sticky oil residues can unbalance the rotating assembly. The compressor wheel, which forces air into the engine, relies on precise aerodynamics. When oil vapors condense on the wheel blades, they disrupt airflow, causing the compressor to work harder and potentially creating hot spots. Over time, this accelerates bearing wear, particularly in journal-bearing turbos where oil film thickness is critical. In ball-bearing turbos, contamination can clog the small oil passages, leading to inadequate lubrication and premature failure.

Additionally, oil vapors that bypass the PCV system and enter the intake manifold can also reach the turbine side through the EGR system, although this is less common. The carbon buildup on intake valves can also indirectly reduce turbocharger life by forcing the engine to run richer or leaner to compensate for changed airflow dynamics, stressing the turbo's wastegate and bypass valve. A catch can mitigates these issues by trapping the oil before it circulates through these sensitive areas.

Key Benefits of Installing a Mishimoto Catch Can

  • Reduced Oil Contamination: The Mishimoto catch can uses a baffle-and-filter design that separates oil mist from crankcase gases with high efficiency, significantly lowering the amount of oil that returns to the intake.
  • Improved Turbocharger Performance: A cleaner intake system allows the turbo to spool more freely and maintain consistent boost pressure, often translating to better throttle response and reduced lag.
  • Extended Engine Life: By minimizing carbon deposits on intake valves and turbo components, the catch can help reduce the need for costly walnut blasting or chemical cleaning of the intake system later in the vehicle’s life.
  • Enhanced Tuning Stability: Aftermarket tunes rely on precise airflow measurements. Oil contamination can skew mass airflow (MAF) sensor readings, leading to fuel trim corrections that reduce power and efficiency. A catch can stabilizes these readings.

For turbocharged engines specifically, the wastegate and blow-off valve also benefit from cleaner crankcase ventilation, as these components can stick or leak when exposed to oily vapors over long periods.

Mishimoto Catch Can Designs: Compact vs Universal vs Vehicle-Specific

Mishimoto offers several catch can configurations to suit different builds. The most common for turbocharged vehicles are their universal catch cans (typically 2-port or 4-port designs) and vehicle-specific kits that include pre-formed hoses and brackets. The universal cans require the user to source proper hose lengths and routing, while the vehicle-specific kits bolt in with minimal modification. Both use an internal baffle that forces air to change direction sharply, causing oil droplets to fall out of the airstream and collect in the bottom of the can. The cans are also designed to be easily disassembled for cleaning, and many include sight glasses to monitor collected oil levels.

For high-boost applications or track cars, Mishimoto also offers a compacted graphite iron (CGI) catch can with an increased internal volume to handle higher volumes of blow-by under sustained load. This is particularly useful for heavily modified turbo engines. The choice between a single-can (PCV side only) and a dual-can (PCV plus valve cover breather side) setup depends on the engine platform; most modern turbo engines benefit from capturing vapors from both sides to fully protect the intake system.

Installation Tips for the Mishimoto Catch Can

Tools Required

  • Socket set (metric and standard, depending on vehicle)
  • Wrenches – typically 10mm, 12mm, and 13mm
  • Flathead screwdriver for hose clamps
  • Hose cutter or sharp utility knife
  • Drill and step-bit (if mounting location requires custom holes)
  • Thread tape or sealant for fittings (if needed)
  • Pliers for spring-style clamps

Step-by-Step Installation Guide

  1. Locate the PCV System: Identify the PCV valve and hose routing on your engine. On most turbocharged engines, the PCV valve is on the valve cover or intake manifold, with a hose running to the intake pipe before the turbo. Also locate the crankcase breather if present.
  2. Remove Factory Hoses: Carefully detach the OEM PCV hose(s) from the intake manifold and valve cover. Use a flathead screwdriver to loosen spring clamps. Inspect hoses for brittleness; if they are hardened, consider replacing them with silicone hoses of the same diameter.
  3. Mount the Catch Can: Choose a secure mounting location away from moving parts, exhaust heat, and areas where oil could drip onto hot components. Common spots are the inner fender well, firewall, or unused bolt holes on the chassis. Use the provided bracket or create a custom one using a drill and step-bit. Ensure the can sits upright so the internal baffle works correctly.
  4. Connect the Hoses: Run a hose from the valve cover/PCV port to the catch can’s inlet. Then run another hose from the catch can’s outlet to the intake tube or manifold. Mishimoto kits include barbed fittings; secure all connections with T-bolt clamps or constant-tension clamps for a leak-free seal. If your engine has separate breather ports, install a second catch can (or use a 4-port universal can) to handle both circuits.
  5. Check for Leaks: Double-check all hose connections and brackets. Start the engine and let it idle. Listen for vacuum leaks (hissing sounds) and inspect for drips or seepage around fittings. Rev the engine gradually; the catch can should not increase crankcase pressure. A smoke test can verify the system is sealed.
  6. Monitor and Drain: After the first drive, check the catch can for collected oil. Most cans need draining every 2,000–5,000 miles depending on driving habits. Mishimoto cans have a drain plug or a bottom fitting for easy disposal of the collected oil.

Installation Considerations for Specific Vehicle Platforms

Some vehicles, such as the Subaru WRX/STI, Volkswagen GTI (EA888), Ford EcoBoost, and Nissan SR20DET, have known PCV system deficiencies that make catch cans especially beneficial. For example, on VW EA888 engines, a catch can positioned between the PCV valve and the intake manifold prevents oil from entering the turbocharger inlet and intercooler piping. On Subaru boxer engines, a dual catch can setup is often recommended because the engine produces high crankcase pressure under sustained boost. Always consult platform-specific forums or Mishimoto’s fitment guide to ensure proper routing.

Cost Breakdown of a Mishimoto Catch Can

The total cost for a Mishimoto catch can installation varies widely based on whether you choose a universal kit, a vehicle-specific kit, and whether you perform the labor yourself. Here is an itemized breakdown:

  • Mishimoto Universal Catch Can Kit: $150–$200 (includes catch can, fittings, and basic mounting hardware).
  • Mishimoto Vehicle-Specific Catch Can Kit: $180–$280 (includes pre-cut hoses, specialized brackets, and instructions).
  • Additional Silicone Hoses or Reducers: $10–$40 if you need to adapt to odd-sized factory ports.
  • Tools (if not already owned): $50–$100 for a basic socket set, hose cutter, and a step-bit.
  • Professional Installation: $150–$350 depending on shop hourly rate and complexity. Some shops charge additional fees if modifications like drilling are required.
  • Ongoing Maintenance: The catch can should be drained every 2,000–5,000 miles—free if you do it yourself. Replacement filter elements (if used) cost around $10–$25 per year.

In total, a DIY installation on a universal kit can cost as little as $150, while a professional install on a vehicle-specific kit might exceed $600. For most enthusiasts, the $200–$350 range delivers a reliable setup that will pay for itself by extending turbocharger life and reducing the need for intake cleaning services.

Expected Performance Gains and Real-World Data

While a catch can does not directly increase horsepower, it can help maintain power output over time. Several independent tests on turbocharged vehicles show that a catch can can reduce intake valve carbon buildup by 40–60% over 50,000 miles when paired with regular oil change intervals. On a dynamometer, cars that had been driven 30,000 miles without a catch can often see a 3–5% horsepower recovery after installation and a subsequent intake cleaning. More importantly, turbocharger compressor maps show that a clean compressor wheel flows more efficiently at low boost levels, improving transient response—a benefit felt particularly in daily driving scenarios.

In long-term fleet studies, vehicles with catch cans experienced fewer turbocharger failures related to oil coking on the compressor blades. While the turbocharger itself is a robust component, the cumulative effect of contamination can lead to early bearing failure or unbalanced shafts. The Mishimoto catch can offers a passive, maintenance-friendly solution that aligns with best practices for high-performance turbocharged engines.

Maintenance and Draining: Best Practices

To keep your Mishimoto catch can working effectively, drain it at every oil change or more often if you drive in heavy stop-and-go traffic or on track days. The collected liquid is usually a mixture of oil and water (emulsion), especially in colder climates. Dispose of it properly at a recycling center or add it to used oil containers. Periodically inspect the internal baffle and filter (if present) for sludge buildup; clean with a solvent spray and compressed air. Most Mishimoto catch cans are designed to be fully disassembled for thorough cleaning. If you notice the can filling rapidly (e.g., 100 mL in 1,000 miles), it may indicate excessive blow-by from worn piston rings or a failing PCV valve—address those issues before they damage the turbo.

Installing a catch can may affect your vehicle’s emission system compliance in some regions. In California, for example, catch cans that modify the PCV system are not CARB-approved and can be subject to fines during smog inspection. However, they are widely used on race cars and off-road vehicles. For street-driven cars, check local laws before installation. Regarding manufacturer warranty: many OEMs will not void the entire warranty for a catch can, but if an oil-related failure occurs and the catch can is deemed to have altered the PCV flow characteristics, the dealer might deny a claim. Choose a vehicle-specific kit that does not require permanent modification (e.g., drilling or cutting OEM hoses) to minimize risk.

Comparison: Mishimoto vs. Competitors

Several other brands offer catch cans for turbocharged engines, including Radium Engineering, Crawford Performance, and Saikou Michi. Mishimoto distinguishes itself through robust construction (billet aluminum or compact graphite iron), clear sight tubes for easy level checking, and a strong warranty (typically lifetime against defects). Radium offers more compact designs with integrated check valves, while Crawford focuses on dual-can setups with high-capacity filters. Mishimoto’s pricing falls in the mid-range, offering a good balance of quality and value. For most DIY installers, the Mishimoto universal can provides an excellent entry point; for those wanting a perfect fit, their vehicle-specific kits are well-engineered with custom brackets and reinforced silicone hoses.

Conclusion: Is a Mishimoto Catch Can Worth It for Turbocharger Longevity?

A Mishimoto catch can is a cost-effective, durable addition to any turbocharged vehicle where oil contamination is a concern. While it won’t fix underlying mechanical issues like worn rings or a faulty PCV valve, it significantly reduces the oil vapor load that reaches the turbocharger and intake system. The result is less carbon buildup, more consistent performance, and a lower risk of premature turbocharger failure. Installation is straightforward for anyone with basic mechanical skills, and the ongoing maintenance is minimal. For the price of one major turbo repair (often $1,500–$3,000), you can install catch cans on multiple vehicles and enjoy years of cleaner operation. Review platform-specific guides and choose the Mishimoto model that fits your engine bay, and you’ll be taking a proactive step toward maximizing your turbocharger’s service life.

For more detailed installation instructions and product specifications, visit Mishimoto’s official site or consult community guides on FT86Club and VW Vortex. Additional technical reading about PCV systems and turbocharger diagnostics can be found at EngineBasics.