Cat-Back Exhaust System: Unleash Hidden Horsepower and More

Exhaust systems play a critical role in engine performance. They channel hot gases exiting the engine and reduce noise pollution from the vehicle. Upgrading to a performance cat-back exhaust system offers enthusiasts an easy way to unlock extra horsepower and torque while enhancing the overall driving experience.

For automotive enthusiasts seeking improved performance, installing an aftermarket cat-back exhaust system is one of the most popular and cost-effective modifications.

What is a Cat Back Exhaust System?

A cat-back exhaust system refers to all the piping and components starting after the catalytic converter to the rear tailpipes. This includes the Mid pipe, Muffler, Tailpipe and Exhaust tips. The 'cat' in cat-back refers to the catalytic converter. Axle-back and header-back exhausts differ from cat-back systems in terms of components replaced. Axle-backs only modify tailpipe and mufflers, while header-backs replace manifolds and catalytic converters too.

Cat Back Exhaust System Meaning

The term "cat-back" comes from the positioning of the catalytic converter in the exhaust system. The “cat” refers to catalytic converter and “back” indicates all piping from the converter rearwards. The catalytic converter is the dividing point that separates the exhaust system into two sections: front section is cylinder head to catalytic converter, rear section is catalytic converter to tailpipe.

Cat Back Exhaust System Benefits

Installing an aftermarket cat-back exhaust unleashes significant performance improvements including:

• 1. Increased horsepower and torque - Decreased backpressure and improved airflow allows the engine to breathe better. This translates into power gains throughout the RPM range.
• 2. Enhanced fuel efficiency - Reduced exhaust resistance enables the engine to operate more efficiently, improving MPG.
• 3. Optimal engine performance - Lower backpressure takes load off the engine, reducing pumping losses and letting it operate as intended.
• 4. Better exhaust note - Aftermarket systems use straight-through mufflers and larger piping to amplify exhaust sound and create an aggressive tone. The sound can be customized based on personal preference.

Cat Back Exhaust System Diagram

Here is a diagram outlining the components in a typical cat-back exhaust system:

Do Cat Back Exhaust Systems Improve Performance?

Many think cat-backs simply make the exhaust louder without real performance gains. In reality, dyno tests demonstrate cat-back systems increase horsepower and torque over stock configurations.

When coupled with supporting mods, cat-back exhausts help unlock the engine's full potential. Upgraded piping reduces backpressure which allows the engine to breathe and function easier.

While stock exhausts are designed for maximum noise reduction and emissions compliance, Aftermarket cat-Back performance exhaust system use higher flowing straight-through mufflers and larger diameter piping for improved performance.

How Does a Cat Back Exhaust System Improve Performance?

There are several ways cat-back exhausts improve horsepower and torque:

• 1. Increased pipe diameter reduces exhaust flow resistance. This allows exhaust gases to escape faster from the combustion chambers.
• 2. Performance mufflers have straight-through or low restriction designs. This minimizes exhaust flow losses compared to stock mufflers.
• 3. Reduced backpressure decreases pumping losses in the engine. The exhaust doesn't have to work as hard to expel gases.
• 4. Improved exhaust scavenging helps pull fresh air and fuel charge into the cylinders for optimal filling.
• 5. Reduced engine load from lower backpressure enables the engine to operate closer to its maximum efficiency.
• 6. Throttle response, Reduced backpressure results in more immediate throttle feedback.
• 7. Amplify exhaust note, The exhaust tone enhancement also adds to the improved driving experience.

Cat Back Exhaust System Horsepower Gain

The horsepower gain from a cat-back exhaust depends on:

• 1. Engine size and configuration
• 2. Displacement and existing power output
• 3. Restrictiveness of the stock exhaust components
• 4. Diameter of piping used in the aftermarket system

Typical horsepower improvements range from 10-25 HP, with higher gains occurring in more restricted stock exhausts.

Higher displacement engines also tend to gain more horsepower from a cat-back exhaust compared to their lower displacement counterparts.

Cat Back Exhaust System Sound

Cat-back systems run straight piping and unconstricted mufflers to enhance sound. Performance mufflers use internal chambers and tuning to achieve the desired sound. Owners can choose a mild, moderate, or more aggressive sound profile.

Exhaust modifications must keep sound levels within local noise regulations. Most cat-back systems are designed to comply with regulations under normal driving.

Cat Back Exhaust System Price

Cat-back exhaust prices range from $500 to $2000. More affordable options use crushed piping, while higher end systems feature mandrel bent pipes.

Stainless steel is more expensive but offers increased corrosion resistance. The number of mufflers and tips also impacts pricing.

Consider paying a shop $75-$150 per hour for professional installation if tackling it yourself seems daunting.

How to Install a Cat Back Exhaust System

A cat back exhaust system replaces everything from the catalytic converter back. This includes the piping, mufflers, resonators, and exhaust tips.

The main steps involve removing the stock exhaust, fitting the new piping and components, realigning hangers and rubber mounts, and tightening all clamps to specification. Cat back installations are considered bolt-on mods and can typically be performed at home with common tools in 3-5 hours.

Parts Needed

• 1. Complete cat back exhaust kit with all piping, mufflers, tips
• 2. OEM gaskets or high temp gasket material
• 3. New exhaust clamps
• 4. Exhaust hanger rubber mounts
• 5. High temperature lubricant or anti-seize compound

Safety Precautions

Exhaust system components reach extremely high temperatures. Always allow time for the exhaust to completely cool before starting any work, at least a few hours after driving. Wear protective gloves when handling exhaust components. Work in a well-ventilated area to avoid carbon monoxide poisoning.

Use a vehicle lift if possible. Safely jack up the vehicle and support it on sturdy jack stands. Never work under a vehicle supported only by a jack. Wear safety glasses to protect your eyes from dirt, debris and released tension springs.

Tools Needed

• 1. Socket set, wrenches, screwdrivers
• 2. Pry bar, hanger pliers, gasket scraper
• 3. Electric/air impact wrench (recommended)
• 4. Jack, jack stands - Anti-seize lubricant

Step 1. Locate the Catalytic Converter

The cat back system will bolt directly to the outlet side of the catalytic converter. Trace the exhaust piping from the engine compartment to locate the catalytic converter, which is part of the stock exhaust system you will be replacing.

Step 2. Remove the Stock Exhaust

Begin by loosening the clamps at the end of the catalytic converter where it connects to the stock piping. Loosen them enough to detach the piping but not fully remove them yet.

Work backwards from the exhaust tips undoing all clamps and hangers. Use hanger pliers to detach rubber mounts and lower exhaust sections carefully as you work back towards the cat. Remove oxygen sensors if necessary.

With all clamps and hangers detached, you can now fully remove the stock exhaust from the vehicle. This may require some forceful wiggling and prying to dislodge components. Be careful not to damage sensors or remaining exhaust pieces.

Step 3. Install the New Exhaust

Loosely attach the new cat back piping to the catalytic converter outlet using a fresh exhaust clamp. Do not fully tighten yet, leave room for adjustments.

Align and insert new rubber mounts on all hangers along the chassis. Use lubricant to ease installation and prevent squeaking.

With all piping aligned and supported, begin tightening all clamps incrementally from front to back. Tighten to manufacturer torque specs, usually around 30-50 ft-lbs.

Step 4. Reconnect Components

Reattach any oxygen sensors to the new piping using anti-seize lubricant on the threads. Reinstall any heat shields or other components removed earlier in process.

Step 5. Inspect and Start Engine

With clamps tightened and parts reinstalled, visually inspect new exhaust for proper clearance around body panels, fuel lines, brake lines, etc. Start the engine and listen carefully for any exhaust leaks or odd sounds. Let idle for several minutes and rev the engine to check for leaks.

Go for a test drive and enjoy the improved exhaust note! Avoid aggressive driving until the exhaust has gone through a few heat cycles to fully seat the gaskets. Check clamps again after the test drive while the exhaust is still warm.

Pro Tips

• 1. Allowing ample cool down time makes removal much easier
• 2. Have an assistant help with alignment and fitting
• 3. A lift allows much better access versus jacking up vehicle
• 4. High temperature lubricant prevents gasket sticking and eases installation