Introduction

Looking to improve your car's performance, sound, or appearance? A sports exhaust is often the first modification considered... but where do you start?

Should I replace the entire line? Just the muffler? The catalytic converter? The midpipe?
And most importantly: what does each piece really change?

In this comprehensive guide, we explain all the parts of an exhaust , what they individually provide, their advantages, disadvantages and effects on:

• The power

• The sound

• Legality

• The budget

And of course, you will discover the solutions offered by Rog : decatalysts, 100/200/300 cell sports catalysts, intermediate tubes, complete stainless steel or titanium lines... with or without remote-controlled valves .

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The 4 main parts of an exhaust

Before talking about modification, let's start by understanding the structure of a typical exhaust on a modern car:

1. Manifold (or turbo outlet)

2. Catalyst (or downpipe if integrated)

3. Intermediate pipe (often with resonator or central silencer)

4. Rear silencer (with or without valves)

All of these parts together make up what is called the complete exhaust system .

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1. The decatalyst: to free the engine

✅ What is it?

A decatalyst is a straight tube that replaces the original catalyst. It removes the filter element for a direct, unrestricted gas flow .

🔧 Effects:

• + Gas flow

• + Responsiveness

• + Rawer and freer sound

• + Power gain (5 to 30 hp depending on engine + reprogramming)

🔊 Sound:

• More present, hoarse, sometimes explosive

• Accentuates pop & bang if mapping is appropriate

• Warning: more acute and aggressive with a titanium line

⚠️ Please note:

• Can turn on engine light without reprogramming

• Not recommended for open roads , to be reserved for track or export

💡 Rog Decatalyst:

• Available for many models

• Compatible with our remote-controlled valve lines

• Simple editing, radically transformed sound

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2. The sports catalyst: for an intelligent compromise

✅ What is it?

A sports catalyst contains a less dense honeycomb structure (100, 200 or 300 cells) than the original one (often 400 to 600 cells). It filters gases, but with less resistance .

🧪 At Rog, we offer:

• 300 cells : discreet, suitable for CT in certain cases

• 200 cells : good compromise between performance and legality

• 100 cells : louder, more efficient, close to the decat

🔧 Effects:

• + Increased flow rate

• + More liberated sound

• + Less heat

• + Possible technical inspection depending on the model

🔊 Sound:

• Its freer , but rounder than a decata

• Accentuates the driving character without being too extreme

✅ Ideal if:

• You want an effective but discreet modification

• You are looking for a compromise between performance and legality

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3. The intermediate tube: the forgotten link that changes everything

✅ What is it?

This is the part located between the catalyst and the rear silencer. It can contain:

• A central silencer

• A resonator

• Or be a straight pipe

🔧 Effects:

• Remove the intermediate silencer = significant sound gain

• Lightens the line

• Little effect on performance, but changes resonance

🔊 Sound:

• Removing this part gives a rawer, more direct sound

• Beware of drones on the highway (continuous low vibrations)

💡 Rog intermediate tube:

• Stainless steel or titanium

• Designed to limit drone

• Available alone or with the complete line

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4. The rear silencer: the heart of the sound

✅ What is it?

This is the last part of the line, visible at the back. It contains:

• Quarrels

• Resonance chambers

• And sometimes… remote-controlled flaps

🔧 Effects:

• Mainly changes volume and timbre

• Little impact on performance (unless very restrictive)

🔊 Sound:

• This is where it all comes together:

  • Material (stainless steel vs titanium)

  • Number of outputs

  • Presence or absence of valves

💡 Rog Silencer:

• Available in a remote-controlled flap version

• Discreet or aggressive design

• Modular sound on demand

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5. The complete line: the ultimate solution

✅ What is it?

A complete line is:

• Decatalytic converter or sports catalyst

• Intermediate tube

• Rear silencer

• All in one perfectly calibrated package

🔧 Effects:

• + Real power gain

• + Heat reduction

• + Weight loss (up to -40% with titanium)

• + Totally transformed sound

🔊 Sound:

• The most coherent and controlled sound experience

• With the flaps: adjustable as desired

💡 Full Rog lines:

• Stainless steel or titanium

• With remote-controlled flaps

• Sport or decatalyzed catalyst depending on use

• Compatible with reprogramming, track or mixed use

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What to change depending on your goal?

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The role of flaps: the detail that changes everything

🎛️ Why flaps are essential:

• Closed mode : discreet, city/CT compatible

• Open mode : racing, raw, enjoyable sound

• Remote control or mobile application

• Present on the majority of Rog lines

You go from a sleeper to a sound monster with just one click.

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Stainless steel or titanium: the effect on sound

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Mistakes to avoid

1. Installing a decata without reprogramming : engine warning light + possible degraded mode

2. Choosing a line that is too noisy without valves : daily discomfort

3. Incorrectly sized diameter : too large = loss of torque, too small = restriction

4. Underestimate the assembly : always plan for a clean and secure installation

5. Believing that a simple silencer is enough : without an intermediate or suitable catalytic converter, limited effect

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Why choose Rog?

• ✅ Wide choice: decat, sport cat, intermediate pipe, silencer, complete line

• ✅ Premium quality: 304 stainless steel, titanium, clean finishes

• ✅ Remote controlled flaps: standard on many models

• ✅ Easy assembly, clear instructions

• ✅ Technical advice and responsive customer service

With Rog , you build your line à la carte, for a consistent, effective and 100% enjoyable result.

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Conclusion

You don't need to change everything to improve your car. But knowing what to change, and in what order , makes all the difference.

• Want a deeper sound? Start with the silencer.

• Need performance? Decatalytic converter or sport catalytic converter.

• Want to transform everything? Choose a complete Rog line.

And above all, think about the flaps: they give you the freedom to adapt your car to each situation .

Build the line that suits you. Unleash the true voice of your engine.