Why a Catch Can Matters for Nashville Performance Vehicles

Nashville’s unique driving environment—stop-and-go traffic on I-440, humidity from the Cumberland River, and a growing community of high-horsepower builds—makes crankcase ventilation management a priority for any serious enthusiast. A catch can isn’t just a bolt-on accessory; it’s a critical line of defense against oil ingestion in your intake system. Without one, oil vapors and moisture recirculate into the intake tract, causing carbon buildup on valves, reduced octane, and potential detonation. This guide dives deep into selecting, installing, and maintaining the right catch can for your Nashville performance vehicle, whether you’re running a boosted LS, a Coyote, or a turbocharged import.

What Is a Catch Can?

A catch can is an inline separator installed in the positive crankcase ventilation (PCV) system. Its job is to capture oil mist, fuel vapors, and water condensate before they re-enter the intake manifold. During normal combustion, blow-by gases (combustion gases that leak past the piston rings) pressurize the crankcase. Modern PCV valves direct these gases back into the intake to be reburned, but they also carry oil droplets that contaminate the intake air. Over time, this oil coats intake valves, intercooler cores, and throttle bodies, leading to performance loss and potential engine damage, especially on direct-injection engines where no fuel washes the valves.

In Nashville’s humid climate, the moisture component becomes even more problematic. Condensation in the PCV system can mix with oil to form sludge. A quality catch can separates these liquids from the air stream, allowing clean, dry air to return to the intake while trapping the contaminants for disposal.

How a Catch Can Works

Most catch cans rely on one or more separation principles: baffling, filtering, or centrifugal action. Inside the can, incoming vapors strike internal baffles or pass through a mesh or stainless steel wool filter. The sudden change in velocity and direction causes heavier oil particles to coalesce and fall to the bottom of the can. Some high-end units incorporate a coalescing filter element that captures even micron-sized droplets. The cleaned air exits through an outlet port connected to the intake manifold or turbo inlet.

A drain valve at the bottom allows easy emptying of collected fluids.

It’s important to note that a catch can is not a simple “breather” that vents to atmosphere (illegal in most states, including Tennessee, for street-driven vehicles). A properly designed catch can is a closed system that maintains the PCV’s functional integrity while filtering out contaminants. For Nashville drivers who track their cars or frequently drive in heavy traffic, a can with a sight tube or level indicator makes maintenance straightforward.

Types of Catch Cans

Air-Oil Separator Catch Cans

The most common type for modern performance cars, these use internal baffles and/or filter media to separate oil from vapors. They are typically sealed units with a threaded drain. Brands like Mishimoto, Radium, and JLT are popular among Nashville tuners for their proven designs and ease of installation. Air-oil separators work well with both naturally aspirated and forced induction setups, though boosted cars may require a dual-can system to handle the increased blow-by under boost.

Breather Catch Cans

These are simple cans with a vented cap that allows crankcase gases to escape to the atmosphere. While legal for off-road or track use only, they are not recommended for daily drivers in Tennessee because they vent hydrocarbon vapors (violating emissions laws) and can create a mess under the hood. Some older or custom builds use them to relieve pressure, but for most Nashville performance vehicles, a closed system is preferable.

High-Capacity Catch Cans

Designed for track cars or high-boost applications that produce excessive blow-by, these cans hold one to three quarts of fluid. They often feature larger inlet/outlet ports (AN-10 or AN-12) and robust mounting brackets. Models from brands like Moroso and Peterson Fluid Systems include internal baffles and optional check valves to prevent vacuum collapse. If you’re running a big turbo LS or a supercharged Coyote with over 700 horsepower, a high-capacity unit is a smart investment.

Compact and Billet Catch Cans

For enthusiasts who want a cleaner engine bay without sacrificing function, compact billet aluminum cans offer a sleek look with effective separation. These are often custom-machined to fit specific vehicles (e.g., C5 Corvette, S197 Mustang) and come with brackets that bolt to existing holes. They typically hold 4–8 ounces, requiring more frequent emptying but taking up minimal space.

Key Factors for Choosing a Catch Can for Your Nashville Build

Material and Construction

Look for 6061 aluminum or 304 stainless steel. Aluminum is lightweight and resists corrosion, while stainless steel is virtually indestructible. Avoid plastic or painted steel cans that can rust or crack under hood heat. Many Nashville performance shops recommend billet aluminum cans because they withstand the vibration and temperature extremes common in high-performance engines.

Capacity and Mounting Location

Consider your oil consumption. A conservative daily driver may only collect a few ounces every oil change, while a track-prepped car can fill a quart in one session. For most street-driven builds, a 16–20 ounce capacity is sufficient and fits easily in available space. Mounting location is critical: you need access to the drain, clearance from moving parts, and avoidance of heat sources like exhaust manifolds. Common spots include the strut tower, firewall, or inner fender.

For Nashville’s humid summers, mount the can as high as possible to avoid water accumulation in the lines.

Compatibility with Your Engine and PCV System

Not all catch cans are universal. For example, LS engines with the standard PCV setup require a specific orientation to avoid oil pooling. Ford Coyote engines have a unique PCV valve location that may need an adapter plate. Turbocharged and supercharged cars often need a dual-valve or check-valve setup to prevent boost from pressurizing the crankcase. Always check with the manufacturer or a local Nashville tuner (like those at Straightline Performance or Nashville Speed and Performance) to confirm fitment before purchasing.

Ease of Installation and Maintenance

Look for a kit that includes mounting hardware, hoses, and instructions. Some catch cans are “plug-and-play” with pre-bent hoses and push-fit connectors, while others require custom routing and cutting. If you’re not comfortable with basic wrenching, consider professional installation. Maintenance ease matters: a dipstick or sight glass lets you check fluid level without opening the can. A bottom drain valve (petcock or quarter-turn) is much cleaner than unscrewing the entire can.

Brand Reputation and Warranty

Stick with brands that have a proven track record in the performance community. Mishimoto offers a lifetime warranty on their aluminum catch cans. Radium Engineering provides detailed documentation and CNC-machined precision. Avoid generic eBay cans with no warranty or technical support. A good catch can is a one-time purchase—don’t risk your engine to save $40.

Installation Best Practices for Nashville Performance Vehicles

Route the PCV Lines Correctly

The catch can should be installed between the PCV valve and the intake manifold (or between the valve cover breather and the intake tube). For boosted setups, place the can between the crankcase vent and the intake before the turbo or supercharger to prevent oil from reaching the intercooler. Use high-quality silicone or reinforced rubber hoses rated for oil and heat. Avoid using cheap PVC tubing that can collapse under vacuum.

Use the Right Fittings

Most catch cans come with barbed fittings, but upgrading to push-to-lock or AN fittings reduces the risk of leaks. For Nashville’s variable weather (hot summers, cold winters), hose clamps should be stainless steel, not zinc-plated, to avoid rust. If your engine has a vacuum signal line (like the brake booster), never T into that for the catch can—you can affect braking performance.

Check the Orientation

Catch cans must be mounted vertically or at a slight angle with the inlet and outlet ports at the top. If mounted sideways, the internal baffling won’t separate oil effectively, and liquid can slosh out the outlet. Follow the manufacturer’s diagram for inlet and outlet assignment—some cans are directional.

Add a Check Valve If Needed

On boosted engines, a check valve (or one-way valve) in the PCV line prevents boost pressure from forcing oil back into the crankcase. Many catch can systems include a check valve, or you can purchase one separately. Without it, you risk pressurizing the crankcase and blowing seals. For Nashville tuners with high-boil applications, this is non-negotiable.

Test for Leaks After Installation

Start the engine and listen for vacuum leaks. Use a smoke machine or soapy water around all connections. A leak can cause a lean condition, rough idle, or check engine light. Also, verify that the PCV valve is functioning correctly—some catch cans can disrupt the PCV system if installed incorrectly.

Maintenance and Troubleshooting

Emptying Schedule

Check the catch can at every oil change or every 1,000 miles, whichever comes first. For daily drivers in Nashville’s humid climate, you may need to empty it more often in winter months due to increased condensation. A good habit is to inspect the fluid color: if it’s mostly milky (water/oil emulsion), your engine is not reaching full operating temperature frequently, which is common in short commute driving. If it’s dark oil, your blow-by might be higher than normal—consider an oil catch can upgrade or look for worn rings.

Cleaning the Filter Element

Some catch cans have a replaceable or washable filter element. For stainless steel wool, you can clean it with brake cleaner and reuse it. For coalescing filters, replace per manufacturer recommendations (typically 20,000–30,000 miles). Dirty filters reduce separation efficiency and can cause the can to bypass oil. Always clean or replace before it becomes restricted.

Troubleshooting Common Issues

Oil leaks from catch can gaskets: Overtightening or under-tightening can cause leaks. Use a torque wrench if specified. Replace gaskets annually if your can uses O-rings.

Can fills up too quickly: More than a quart every 1,000 miles indicates excessive blow-by. Check for worn piston rings, valve seals, or a clogged PCV valve. A compression test can help diagnose.

Check engine light after installation: If your car has a MAF sensor and the catch can causes a lean condition (leak), the ECM may trigger a P0171/P0174 code. Double-check all hose connections and ensure the can is not restricting flow. Some high-end systems require a tune adjustment for optimal MAF signal.

Can freezes in winter: In Nashville’s occasional sub-freezing temps, moisture can freeze inside the can, blocking airflow. If this happens, move the can to a warmer location (closer to the engine block) or insulate the hoses. Some aftermarket cans have a heater element option.

When to Upgrade or Downsize

If you’re constantly emptying a small can, consider a larger capacity unit. Conversely, if your can is never more than a quarter full at oil changes, you may have overkill capacity or your PCV system isn’t functioning properly. A catch can should collect at least some oil; zero accumulation could mean the can is bypassing entirely. Check the routing and internals.

Conclusion

A well-chosen catch can is a small but mighty upgrade that protects your Nashville performance vehicle’s engine from carbon buildup, detonation, and sludge. By understanding the different types, materials, and installation nuances, you can select a unit that matches your driving style and power level. Whether you’re cruising Broadway or chasing tenths at Music City Raceway, a quality catch can from a reputable brand will pay dividends in engine longevity and consistent performance. Invest in a proper kit, install it correctly, and make emptying the can part of your routine maintenance—your engine will thank you.

For further reading, check out EngineLabs’ technical breakdown of catch cans and Mishimoto’s engineering analysis. For Nashville-specific tuning advice, consider contacting Nashville Speed and Performance or Straightline Performance for personalized recommendations.