How to Choose the Best Cell Cats for Your Downpipe

When it comes to maximizing your car’s performance, selecting the right downpipe is crucial. But an often-overlooked factor in this upgrade is the type of catalytic converter or “cell cat” integrated with the downpipe. The choice of a catalytic converter plays a significant role in balancing performance, emissions, and sound quality. In this article, we’ll break down everything you need to know about choosing the best cell cats for your downpipe, whether you’re seeking more horsepower, improved efficiency, or just an enhanced driving experience.

What Are Cell Catalysts (Cats) and Why Do They Matter?

Catalytic converters are emissions-control devices designed to reduce harmful pollutants from your vehicle’s exhaust gases. The “cell” in cell cats refers to the honeycomb-like structure inside the catalytic converter. This honeycomb is made of precious metals like platinum, palladium, and rhodium, which react with exhaust gases to neutralize harmful substances like carbon monoxide, hydrocarbons, and nitrogen oxides.

The density of the honeycomb is measured in cells per square inch (CPSI). This density determines how restrictive the cat is to exhaust flow. Here’s why it matters:

• Higher CPSI (e.g., 400-600 CPSI): More restrictive, better at reducing emissions, and quieter.
• Lower CPSI (e.g., 100-200 CPSI): Less restrictive, allowing more exhaust flow for better performance and sound, but less effective at emissions control.

When selecting a cell cat for your downpipe, the CPSI and material construction directly affect performance, sound, and emissions compliance.

Key Factors to Consider When Choosing Cell Cats for Your Downpipe

1. Performance Goals

Your performance goals are the primary factor in choosing the right catalytic converter.

• High-Performance Builds: If you’re looking to push your car’s performance limits, a high-flow catalytic converter (100-200 CPSI) or even a catless downpipe may be your best option. High-flow cats reduce exhaust backpressure, allowing for quicker turbo spool times and increased horsepower.
• Balanced Builds: For those who want a mix of performance and emissions compliance, a mid-range cat (200-300 CPSI) is a solid choice.
• Daily Drivers: If your car is primarily for daily commuting and must meet strict emissions regulations, a high-CPSI catalytic converter (400+ CPSI) is ideal.

2. Emissions Regulations

Local emissions laws can dictate your choice of catalytic converter. In regions with strict regulations, such as California’s CARB (California Air Resources Board) standards, you’ll need to opt for a catalytic converter that meets compliance requirements.

If you live in an area with relaxed emissions testing, you may have more freedom to choose high-flow or catless options, but always weigh the environmental impact and legal risks.

3. Material and Build Quality

The materials used in the construction of the catalytic converter significantly impact its durability and efficiency.

• Metallic Cats: These are lighter and more durable, making them ideal for high-performance builds. They heat up quickly, improving catalytic efficiency during cold starts.
• Ceramic Cats: These are more cost-effective and common in OEM applications. While not as durable as metallic cats, they’re sufficient for most daily drivers and moderate performance builds.

Always choose a reputable brand with proven reliability to ensure your catalytic converter can withstand the high temperatures and pressures of a performance-oriented exhaust system.

4. Sound Preference

The density of the catalytic converter also affects the sound of your exhaust.

• Low CPSI Cats or Catless Downpipes: Louder and more aggressive exhaust notes, ideal for enthusiasts who want a sporty, raw sound.
• High CPSI Cats: Quieter and more refined, suitable for those who prefer subtlety or have noise restrictions to consider.

5. Turbocharged vs. Naturally Aspirated Engines

The type of engine you have can influence your choice.

• Turbocharged Engines: A high-flow cat or catless downpipe is often preferred to reduce turbo lag and improve spool times.
• Naturally Aspirated Engines: You can still benefit from a high-flow cat, but the gains may not be as pronounced compared to turbocharged setups.

6. Budget Considerations

Performance upgrades can quickly become expensive, so it’s essential to consider your budget. While high-performance metallic high-flow cats are more costly, they provide better long-term durability and performance. Ceramic cats, on the other hand, are more affordable and sufficient for most needs.

Types of Cell Cats: A Breakdown

To make an informed decision, let’s dive into the common types of catalytic converters used in downpipes:

1. OEM Catalytic Converters

• CPSI: Typically 400+
• Use Case: Ideal for daily drivers and regions with strict emissions laws.
• Advantages: Highly effective at emissions control and quieter exhaust notes.
• Disadvantages: Restrictive to exhaust flow, reducing potential performance gains.

2. High-Flow Catalytic Converters

• CPSI: 100-300
• Use Case: Perfect for enthusiasts seeking a balance of performance and emissions compliance.
• Advantages: Improved exhaust flow, better horsepower gains, and sporty exhaust notes.
• Disadvantages: May not meet emissions standards in some regions.

3. Catless Downpipes

• CPSI: N/A (No catalytic converter)
• Use Case: For maximum performance in racing or track-only vehicles.
• Advantages: Zero restriction, maximum power gains, and aggressive exhaust sound.
• Disadvantages: Non-compliant with emissions standards, increased environmental impact, and potential for unpleasant exhaust odors.

Installation Tips for Downpipe Cell Cats

Installing a new downpipe with a catalytic converter is a significant modification that requires careful attention. Here are some tips:

1. Professional Installation: If you’re unsure about the process, have a professional install the downpipe to ensure proper fitment and avoid leaks.
2. Tuning: After installing a high-flow or catless downpipe, a custom ECU tune is often necessary to optimize performance and avoid triggering a check engine light.
3. Regular Maintenance: High-performance catalytic converters may require more frequent checks to ensure they remain effective.

Final Thoughts

Choosing the best cell cat for your downpipe boils down to understanding your performance goals, emissions requirements, and budget. Whether you’re building a high-performance track car or upgrading your daily driver, the right catalytic converter can make all the difference in balancing power, sound, and compliance.

Take the time to research your options, consult with experts, and invest in a high-quality product to ensure your exhaust system performs at its best. With the right setup, you’ll enjoy enhanced performance, a satisfying exhaust note, and peace of mind knowing your vehicle is running efficiently and responsibly.