Ford Focus RS Mk2 Tuning Guide
Ford Focus RS Mk2 Tuning Guide
The Ford Focus RS Mk2, with its 2.5-litre turbocharged Duratec engine, is a highly tunable performance car. Whether you're looking to improve power, handling, or overall driving experience, there are various modifications available to enhance the RS Mk2's capabilities. In this guide, we'll cover the key tuning options, common boosting issues to address, and important considerations when upgrading your Focus RS Mk2.
If you'd like to browse our full range of available RS Mk2 parts, click here!
1. Performance Tuning: Power and Handling
The Focus RS Mk2 is already a potent performance vehicle straight from the factory, but there’s plenty of potential for further tuning. Here are the primary areas to focus on when tuning your RS Mk2:
Engine Remapping / ECU Tuning
One of the most straightforward ways to increase the power output of your Focus RS Mk2 is through engine remapping (ECU tuning). A remap adjusts the engine control unit (ECU) to optimise performance, allowing the turbocharged engine to produce more power and torque. Depending on the remap, you can expect power increases of around 30-50 horsepower, which results in noticeable improvements in acceleration and responsiveness. As you progress through hardware modifications, the end power level may differ.
When considering a remap, it's important to choose a reputable tuner who understands the Focus RS Mk2’s engine and capabilities. A good remap should also consider other supporting modifications such as an upgraded intercooler and intake system to ensure reliable performance.
Turbo Upgrades
The 2.5-litre engine’s turbocharger is already capable of handling significant boost, but for those looking for even more power, upgrading the turbo is a common option. A larger turbo will increase airflow, allowing for higher boost levels and more power. Upgrades can range from hybrid turbos to full turbo replacements, with gains of up to 100+ horsepower possible with a well-matched setup.
If you're upgrading the turbo, it's essential to monitor supporting components such as the fuel system and exhaust to handle the increased power output effectively. Additionally, upgrading the fuel injectors and fuel pump may be necessary to avoid fuel starvation. The sky truly is the limit, with some Focus RS models seeing over 1000bhp with all supporting modifications and hardware/software.
Intake and Exhaust Upgrades
Upgrading the intake and exhaust systems on your RS Mk2 can also contribute to improved performance. A high-flow air filter or an upgraded intake system can improve airflow, while a larger intercooler will reduce intake temperatures, allowing the engine to make better use of the boost. JXL Performance recommends K&N Performance Intake System for Focus RS Mk2
On the exhaust side, a high-flow downpipe, sports cat, and larger exhaust system will help improve exhaust flow, which can increase both power and throttle response. Be mindful of local emissions regulations when choosing exhaust components, as modifications like decat pipes may not be street legal in some regions. JXL Performance recommends Milltek Sport Exhaust upgrades for your RS Mk2.
It is also worth noting that once you get to around 400bhp give or take, it is worth upgrading your intake plenum, higher boost pressures can cause issues with old, weary units. JXL Performance recommends upgrading to the AIRTEC Motorsport Inlet Plenum for Mk2 Focus (ST & RS)
Suspension and Handling Upgrades
While the RS Mk2 already has a sportier suspension than regular Focus models, further upgrades can significantly enhance handling and cornering performance. Consider upgrading the springs, dampers, and sway bars to tighten the handling, reduce body roll, and improve stability during high-speed cornering.
Upgraded coilovers allow for adjustable ride height and damping, giving you more control over your car’s setup. Additionally, adding a strut brace or rear sway bar will increase chassis rigidity, improving handling even further.
To view our full range of suspension upgrades for your Focus RS - click here!
2. Boosting Issues to Address
Before you start tuning your RS Mk2, it’s essential to ensure that the turbocharging system is functioning correctly. Boosting issues are common on these cars, and they can negatively affect performance and power delivery if not addressed. Here are the key components to check:
MAP Sensor
The Manifold Absolute Pressure (MAP) sensor measures the air pressure in the intake manifold, providing vital information to the ECU about boost levels. A faulty or dirty MAP sensor can lead to incorrect boost readings, causing performance issues or inconsistent power delivery. If you're experiencing boosting issues, start by inspecting the MAP sensor and cleaning or replacing it if necessary.
MAF Sensor
The Mass Air Flow (MAF) sensor measures the amount of air entering the engine, helping the ECU adjust the fuel mixture. A dirty or faulty MAF sensor can lead to incorrect air-fuel ratios, affecting power delivery and fuel economy. Cleaning the MAF sensor or replacing it if it’s faulty can improve boosting performance and restore smooth engine operation.
Boost Solenoid
The boost solenoid controls the boost pressure by regulating the wastegate. If the boost solenoid is malfunctioning, it can lead to issues like overboosting, underboosting, or inconsistent boost levels. A faulty solenoid may cause the turbo to underperform, even with a remap or other performance upgrades. If you suspect boost issues, check the solenoid and replace it if necessary.
Datalogging with Forscan
If you’ve checked the above components and still experience boosting problems, it may be time to datalog your vehicle using a tool like Forscan. Forscan allows you to monitor the car’s performance in real time, providing valuable data on boost levels, air-fuel ratios, and other engine parameters. This data can help pinpoint issues and ensure the car is running optimally before proceeding with further tuning.
3. Supporting Modifications for Reliability
While performance upgrades are exciting, it’s essential to consider supporting modifications to maintain the car’s reliability, especially when pushing for higher power levels. Here are a few additional upgrades to consider:
Upgraded Clutch and Flywheel
With the increase in power, you may need a stronger clutch to handle the additional torque. An upgraded performance clutch with a lighter flywheel can provide better power delivery, more consistent engagement, and improved driving feel. A heavy-duty clutch kit is especially recommended if you're planning on significant turbo upgrades or running higher boost levels.
Our recommendation for clutches/flywheel very much dependent on wear and usage. You can check out our full range of RS Mk2 drivetrain parts here
Oil Cooler, Upgraded Radiator and Intercooler
As the Focus RS Mk2 is a high-performance vehicle, keeping the engine cool is crucial, especially during aggressive driving. An upgraded oil cooler and larger radiator can help maintain optimal engine temperatures, preventing overheating and reducing the risk of premature engine wear.
It's relatively common knowledge that the Focus Mk2 RS & ST intercooler systems could be improved upon, if you are considering to tune your vehicle, adding an intercooler will not only prevent the car from pulling back due to heat, therefore giving you access to more power, more of the time, they also help keep the car content on hot days, during hard drives, or even track use.
You can find a full list of our available cooling options for your RS Mk2 here
Upgraded Fuel System
Higher performance often demands more fuel, so upgrading the fuel injectors and fuel pump is important when tuning for additional power. A higher-flow fuel pump will ensure consistent fuel delivery, while larger injectors will provide the necessary fuel for higher power levels. The RS Mk2 comes from factory with 440cc injectors, these are a common upgrade for the little brother (ST Mk2), if you're upping the power in your RS, you may need 500cc, 750cc, or even 1000cc+ injectors dependent on your power goals.
Conclusion
The Ford Focus RS Mk2 offers plenty of tuning potential, from increasing power output with a remap or turbo upgrade to improving handling with suspension modifications. However, before diving into performance upgrades, it’s crucial to ensure that the engine is running correctly, especially when it comes to boosting issues. Start by checking the MAP sensor, MAF sensor, and boost solenoid, and consider using Forscan for further diagnostics.
Supporting modifications, such as upgrading the clutch, oil cooler, and fuel system, can help maintain reliability as you push the car’s limits. With the right tuning approach, your Focus RS Mk2 can deliver thrilling performance while remaining a reliable and exciting car to drive.