Mercedes CLA45 AMG C118 Tuning Guide

The Mercedes-Benz A45, A45S (W177), and CLA45S (C118) are performance-oriented models that come equipped with a 2.0-litre turbocharged engine, delivering impressive power straight from the factory. The A45S, in particular, is one of the most powerful four-cylinder production engines available. However, some owners may still be interested in enhancing their vehicles further, whether for more power, improved driving pleasure, or a more personalised aesthetic.

If you're considering tuning your A45, A45S, or CLA45S, it’s essential to understand the potential benefits and limitations of modifying these high-performance vehicles. This guide will walk you through the key considerations and tuning options for these models, helping you make informed decisions on how to approach modifications.

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Understanding the Factory Setup

Out of the factory, the A45 (387 bhp) and A45S (415 bhp) W177, along with the CLA45S (around 415 bhp), offer outstanding performance thanks to their turbocharged engines, 4MATIC+ all-wheel drive systems, and 8-speed dual-clutch transmissions. With figures like these, many owners may find that the stock performance is more than adequate for everyday driving or even spirited driving on a track.

Given that these models are already highly strung in terms of power output, you might find that tuning for more horsepower is unnecessary for some. For others, however, tuning is an appealing option to extract more performance or to personalise the car's aesthetics and driving dynamics.

Power Upgrades: Should You Tune for More Power?

For those looking to increase engine performance, there are several ways to enhance the power output of the 2.0-litre turbocharged engine. However, it is important to recognise that these vehicles are finely tuned from the factory, and pushing the engine too hard can affect long-term reliability and warranty conditions. Always consult with a trusted tuner or Mercedes-Benz specialist before committing to any power modifications.

Some common power upgrades include:

ECU Remapping/Tuning

One of the most popular tuning methods for the A45, A45S, and CLA45S is remapping the Engine Control Unit (ECU). An ECU remap can optimise the engine's performance, improving the power output, throttle response, and overall driving experience.

• A45 Remap: A stage 1 remap can typically add around 20-30 bhp, while a more aggressive remap can increase the power to approximately 420-450 bhp.
• A45S and CLA45S Remap: These models already push the limits of the 2.0-litre engine, so remapping can bring the output to around 440-470 bhp depending on the tune and additional upgrades.

However, it’s important to be cautious with power increases on these models due to the delicate balance between performance and reliability. Over-tuning can lead to stress on the turbocharger, fuel system, and transmission.

Turbocharger Upgrades

For those looking for substantial power gains, upgrading the turbocharger is a more involved, but effective option. A larger or hybrid turbo can significantly increase the airflow into the engine, providing more power, especially at higher revs.

However, this modification is more costly and will require a comprehensive understanding of your vehicle’s current setup. Expect to see power figures in excess of 500 bhp with the right turbo upgrade, but bear in mind that this can put a considerable strain on engine components, so reinforcing the engine internals might be necessary.

Intake and Exhaust System

Improving the intake and exhaust systems can help release more performance potential. A high-performance intake can improve air intake efficiency, while a less restrictive exhaust system (including a sports or performance exhaust) can reduce backpressure, allowing the engine to breathe more freely.

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Upgrading to a larger intake or an upgraded air filter system is a relatively straightforward way to increase airflow without major engine work, while a full performance exhaust system can improve both sound and power. Keep in mind that some exhaust upgrades can increase turbo spool noise, adding a more aggressive tone that many enthusiasts enjoy.

Handling and Suspension Upgrades

While many owners of the A45, A45S, and CLA45S may not wish to increase power, tuning the handling and suspension systems is a popular modification choice. The factory suspension offers great performance, but there are several ways to enhance the driving experience further.

Suspension Kits

Upgrading the suspension can improve handling and cornering. Performance coilovers or adjustable dampers can give you the ability to fine-tune the ride height and damping, making it easier to tailor the vehicle to your driving preferences.

For track-focused enthusiasts, a sportier suspension setup may offer more aggressive handling, while still maintaining road comfort for daily use. However, keep in mind that lowering the car too much could negatively affect ride quality, and may even lead to clearance issues in some circumstances.

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Braking System

If you are pushing more power or increasing track usage, an upgraded braking system may be necessary. Aftermarket brake pads, discs, and performance fluid can significantly improve braking performance. You can also consider larger diameter brake discs or carbon-ceramic brake systems if you're looking to take your vehicle to the track regularly.

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Aesthetic and Interior Upgrades

For those more interested in personalising their car’s look and feel, there are a number of aesthetic and interior upgrades to choose from. These won’t directly affect performance but can enhance the overall driving experience.

Wheels and Tyres

Upgrading the wheels and tyres is one of the most common aesthetic modifications. Lighter, larger, or more unique alloy wheels can drastically alter the appearance of the car. Performance tyres can improve grip and handling, particularly in wet or dry conditions, and can be a great way to enhance driving pleasure.

Interior Enhancements

Inside the cabin, many owners opt for upgrades such as sports seats, steering wheel options, or custom trim. Upgraded leather upholstery, ambient lighting, or carbon fibre inserts can all contribute to a more luxurious, sporty feel inside the vehicle.

Body Kits and Spoilers

For a more aggressive appearance, many A45/A45S/CLA45S owners fit body kits, spoilers, or diffusers. These modifications not only enhance the car’s visual appeal but can also improve aerodynamics and stability at higher speeds.

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Things to Keep in Mind

Reliability and Warranty: Tuning any high-performance vehicle can affect its long-term reliability. Always check with your chosen tuner about any potential risks to your car's warranty. Some modifications, especially those affecting power and engine internals, may void your warranty.

Consult a Professional: Given the complexity of tuning these high-performance models, always work with a reputable tuner with experience in Mercedes-AMG vehicles. A professional tuner will be able to recommend the right upgrades that maintain your vehicle’s reliability and maximise performance.

Legal Considerations: Ensure any modifications you make comply with local regulations, especially if they affect emissions, noise, or safety. Always check that your modifications are road legal.

Conclusion

The A45, A45S, and CLA45S are already high-performance machines straight from the factory, but for those who want to push the boundaries or personalise their driving experience, tuning options are abundant. Whether you're looking to enhance power, improve handling, or add some visual flair, there are plenty of modifications available.

However, it's essential to approach tuning with caution, especially given the finely balanced engineering of these vehicles. Always consult with a professional tuner and consider the long-term effects of your modifications on the car’s performance, reliability, and warranty. With the right upgrades, you can make your A45, A45S, or CLA45S even more enjoyable to drive and uniquely yours.