Catalytic Converters & Systems

High Flow Catalytic Converters for Modified Engines

A high flow catalytic converter uses a less dense substrate to cut exhaust backpressure on modified engines. Stock converters commonly use about 400-600 cells per square inch. High-flow designs commonly drop to about 100-300 cells, which leaves more open area for exhaust gas.

You'll see most of the benefit on engines with forced induction, bigger cams or other airflow upgrades. On a stock engine with factory airflow, you probably won't feel much difference. If you're running a turbo or supercharger, a high-flow converter reduces the restriction downstream of the engine, which matters more as boost goes up.

A converter upgrade often happens alongside other exhaust work. Compare cat-back vs. axle-back exhaust systems to plan the pipes, mufflers and tips behind the converter. Before you buy, check your state's emissions rules, since compliance varies by unit and by state.

Direct-Fit vs Universal Catalytic Converters

A direct fit catalytic converter bolts into the factory location, while a universal catalytic converter requires cutting and welding. A direct-fit converter uses the correct flanges and hangers for a specific vehicle. Applications here include Jeep Wrangler, Ford/Lincoln, Chevrolet/GMC, Dodge Ram 1500, Mercedes-Benz, BMW and the 1986-1991 Chevrolet Corvette.

MagnaFlow accounts for most listings in this category. JEGS vehicle-specific replacement converters are labeled by position, such as front, rear, center or left/driver side. They cover models like the Ford F150, Ford Escape and Toyota Prius, and aFe Power offers a direct-fit converter too.

A universal converter fits many vehicles, but only if the inlet and outlet diameter match your pipe. Listed sizes include 2 in. round and 2.25 in. angled in/out.

Learn how to measure exhaust inlet and outlet diameter before you order. If you don't have welding tools, plan on a shop to handle the install.

CARB Compliant vs EPA Compliant Catalytic Converters

You need a CARB compliant catalytic converter in California and CARB-adopting states, while an EPA compliant catalytic converter is for vehicles registered elsewhere. A CARB-approved converter carries an Executive Order (EO) number. That number confirms the part is approved for your vehicle.

Federal/EPA units are often called 49-state converters. They aren't legal on vehicles registered in California or states that follow CARB rules. If you're unsure which rules apply, check with your state's emissions program before you order, since the wrong unit can mean a failed inspection.

An OBD-II catalytic converter also has to keep your onboard monitors happy. If the converter can't meet the system's efficiency checks, you'll likely see a check engine light.

This category includes a Universal California OBD-II Compliant unit for builds that need a weld-in, CARB-approved option. You can also browse all catalytic converter and emissions parts to find related components.

Understanding MagnaFlow Converter Grades

MagnaFlow grades separate converters by application and emissions compliance, so the right grade depends on your vehicle and where it's registered. Here's what you'll find in this category.

• Standard Grade converters
• HM Grade converters
• OEM Grade converters
• California Grade CARB Compliant converters
• Federal/EPA Compliant converters
• Stainless steel construction on select units
• Manifold catalytic converters for select BMW models

Don't choose a grade by name alone. Check each listing's fitment notes and compliance label against your vehicle and state. A grade that's right for one vehicle may not be approved for another, even on a similar model or engine.

Manifold converters mount at the exhaust manifold, close to the engine. That makes them specific to the engine they're built for, so confirm the engine code before you order. If you're replacing more than the converter, browse headers and exhaust parts for the rest of the system.

Catalytic Converter Replacement Tips

Catalytic converter replacement usually starts with a diagnosis, since a failing converter often points to another engine problem. Common signs include a check engine light, a rattle under the vehicle, a rotten-egg smell and a failed emissions test.

A clogged converter can also cause sluggish acceleration. Read about why an engine loses power under load to rule out other causes. Fix misfires, oil burning or coolant leaks first, or they can damage the new converter.

Use the Add a Vehicle tool to filter by year, make and model or VIN. Then check the listing for the converter position, such as front or rear, and confirm the compliance label matches your state.

While the old unit is out, inspect the exhaust pipe-to-converter parts and replace any that are worn. Converter shields, including skid plates for models like the Tacoma, add protection from road debris.