Tuning the Mazda SkyActiv-G

"Comprehensive guide to tuning the Mazda SkyActiv-G engine!"

Let's delve into the world of Mazda's SkyActiv-G engine and its tuning potential, focusing on the best modifications for power gains and highlighting common tuning mistakes.

SkyActiv-G engines are renowned for their efficiency and performance, making them popular choices for car enthusiasts.

The SkyActiv-G engine, developed and released by Mazda, was part of a broader initiative known as the SkyActiv Technology program.

This program aimed to improve fuel efficiency and reduce emissions without compromising driving performance.

The SkyActiv-G engine was released to replace several of Mazda's previous engines, notably the MZR line, including the MZR 2.0-liter engine.

SkyActiv-G Engine Overview

  • Model Years and Engine Sizes: The SkyActiv-G series, introduced by Mazda around 2011, comes in various sizes, including 1.5L, 2.0L, and 2.5L variants. These engines are found in models such as the Mazda3, Mazda6, and CX-5.

Engine Technology: Key features include high compression ratios (around 14:1), direct fuel injection, and innovative exhaust systems. This technology results in improved fuel efficiency and reduced emissions without sacrificing performance.

At the heart of SkyActiv Technology is the goal of improving fuel efficiency. SkyActiv-G engines achieve this through high compression ratios (around 14:1), which is significantly higher than typical engines at the time. This leads to more efficient fuel combustion.

With increasing global awareness and regulation around environmental impact, reducing emissions became a crucial factor. The SkyActiv-G engines, with their advanced combustion technology, helped in significantly lowering CO2 and other harmful emissions.

Despite the focus on efficiency and emissions, Mazda wanted to ensure that driving pleasure and performance were not compromised.

The SkyActiv-G engines were designed to provide a responsive and engaging driving experience, a hallmark of Mazda vehicles.

The SkyActiv-G was a step forward in terms of technology, incorporating direct fuel injection, optimized intake ports, and new piston designs. These advancements allowed for better air-fuel mixture and combustion efficiency.

Best Mods for SkyActiv-G

  1. ECU Remapping/Tuning: Adjusting the engine control unit (ECU) can significantly enhance performance, particularly torque and horsepower. This should be a priority mod.
  2. Turbocharging: Adding a turbo kit, especially for naturally aspirated models, can massively boost power outputs. It's a more involved mod but offers substantial gains. The turbo engines will benefit from a larger turbo unit for higher power gains.
  3. Exhaust System Upgrades: A high-flow exhaust system can improve engine breathing, leading to better performance.
  4. Air Intake Systems: Upgraded intakes ensure more air reaches the engine, improving combustion and power.
  5. Throttle Body Upgrade: A larger or more efficient throttle body can improve air flow, leading to potential gains in power and responsiveness.

Each engine responds better to more aggressive cam durations than others.

The ECU mapping and fuelling also have a large bearing on the torque gains you'll achieve.

Extending exhaust or intake durations can alter the torque band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

SkyActiv-G Tuning Stages

Stage 1 SkyActiv-G modifications: Drilled & smoothed airbox, Intake headers, Panel air filters, Remaps/piggy back ECU, Sports exhaust manifold.

Stage 2 SkyActiv-G modifications: Fuel pump upgrades, Sports catalyst & performance exhaust, high flow fuel injectors & pump, Throttle body upgrades, Ported and polished head, induction kit.

Stage 3 SkyActiv-G modifications: Competition cam, Adding or Upgrading forced induction (turbo/supercharger), Crank and Piston upgrades to alter compression, Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions.

The SkyActiv-G power plant make great tuning projects and we're happy to report there are increasing numbers of modifications and tuning parts about.

ECU mapping should help to fully realize the full potential of all the upgrades you've done to your SkyActiv-G.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved often depend much on the upgrades you've fitted and the condition of your engine.

It is the aim to any engine performance tuning job to feed air and fuel into each cylinder

Intake carry the air during the suck phase from the filter and allow it to be drawn into the engine cylinders.

The size of bore and shape and rate of flow of the Intake manifold can make a big change to fuel atomisation and engine efficiency on the SkyActiv-G.

We often see headers are improved through an upgrade, although some OEM provide well optimised headers.

Increasing the SkyActiv-G valve size, doing some port matching and head flowing will also improve bhp, & more importantly will permit raising the bhp increase on other tuning mods.

Turbo upgrades for the SkyActiv-G

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your SkyActiv-G

Turbocharging the SkyActiv-G Engines

The SkyActiv-G engine lineup from Mazda includes both naturally aspirated and factory turbocharged variants. Upgrading the turbocharger on these engines can lead to significant power gains due to the increased air intake, allowing for more fuel combustion.

Naturally Aspirated SkyActiv-G Engines

Turbocharging Benefits Adding a turbocharger to a naturally aspirated SkyActiv-G engine can drastically increase power output. The turbo forces more air into the engine, enabling it to burn more fuel and generate more power.

Upgrade Considerations When adding a turbocharger, it's important to consider the engine's capacity to handle increased pressure and temperature. Upgraded internal components might be necessary to cope with the additional stress.

Factory Turbocharged SkyActiv-G Engines

Reliability of Mods

The factory turbocharged SkyActiv-G engines often come with more robust components (like forged internals) that are better suited to handle tuning and increased power outputs.

Turbocharger Upgrades

Upgrading the existing turbocharger can refine performance. This might involve increasing the size for higher top-end power or optimizing the current setup for better efficiency and response.

Common Considerations for Both:

Balancing Turbo Size

Larger turbochargers can lead to lag at lower RPMs, while smaller ones may offer quick spooling but limited high RPM power gains. It's crucial to choose a size that balances responsiveness and peak power for your needs.

Advanced Turbo Technologies

Variable Vane Turbochargers

These adjust the vane angle based on engine speed, reducing lag and improving top-end performance.

Twin-Scroll Turbochargers

These use two separate channels for exhaust gases, improving efficiency and engine scavenging, leading to better overall performance.

Air Flow Sensor Limitations

Upgraded SkyActiv-G engines may encounter limitations with the stock Mass Air Flow (MAF) or Manifold Absolute Pressure (MAP) sensors. These sensors might not accurately read the increased air volume, necessitating an upgrade for optimal performance.

Cautionary Notes:

  • Engine Stress Upgrading a turbocharger significantly increases stress on the engine. There are instances where SkyActiv-G engines have failed (such as throwing a rod) after a turbo upgrade due to inadequate supporting modifications.
  • Quality Parts and Tuning It's crucial to use high-quality parts and professional tuning to ensure reliability and performance gains. Poorly chosen or installed upgrades can lead to engine damage.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp at a much lower level.

Adding a supercharger or additional turbo will make large bhp gains, although more difficult to configure. We have this article on twincharging if you want to read more.

Uprating SkyActiv-G fuel injectors

Don't miss you'll need to boost the fuel system when you are increasing the power - it makes the car more thirsty. Most tuners we speak with say to over specify your flow rate on the injectors.

The accepted safe increase is to add 20% to the flow rate when fitting an injector, helps cope with injector deterioration and allows a bit of spare capacity should the engine require more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

You can't beat the convenience of a well thought out tuning package for the SkyActive-G and BBR have come to the rescue here with a couple of impressive options.

  • BBR Super 170: Offers a significant power boost to 170 bhp, primarily through ECU tuning. Ideal for those seeking a noticeable improvement in performance without extensive modifications. Price: £499.00 (installation included).
  • BBR Super 185: Builds on the Super 170 with additional enhancements like a stainless steel 4-2-1 exhaust manifold and a cold air intake system, pushing power to 185 bhp. Price: £1795.00 fitted, with options to modify the package.
  • Optional BBR Sports Exhaust System: For those desiring a sportier exhaust note, this system is compatible with 2.0-liter Skyactiv engines in Mazda models.

Best SkyActiv-G performance exhausts

When upgrading the exhaust system on a SkyActiv-G engine, the goal is to enhance flow efficiency without compromising the exhaust velocity. This can be achieved by selecting an exhaust system that balances diameter, material, and design.

Key Points to Consider:

  1. Optimal Diameter: For SkyActiv-G engines, exhausts with diameters ranging from 1.5 to 2.5 inches are generally ideal. This range provides a good balance between flow rate and velocity.
  2. Material and Design: The material (like stainless steel) and design (such as mandrel bends) are crucial for durability and flow efficiency.
  3. Catalytic Converter: Upgrading to a high-flow catalytic converter can significantly reduce exhaust back pressure while maintaining emissions compliance.

Typically exhaust restrictions can be traced to the catalysts installed, so adding a freer flowing performance alternative will help avoid this restriction. But these catalyst mods are not legal in all regions.

Additional Considerations:

  • Sound vs. Performance: Be mindful of the trade-off between a more aggressive exhaust note and actual performance gains.
  • Legal Compliance: Ensure that the exhaust system complies with local emissions and noise regulations.
  • Professional Installation: Proper installation is key to ensuring the exhaust system functions correctly and provides the expected performance benefits.
  • Compatibility: Make sure the exhaust system is compatible with other modifications you might have or plan to add.

Tuning Mistakes to Avoid

  • Ignoring Engine Health: Always ensure your engine is in good health before starting any tuning projects.
  • Mismatched Components: Avoid using parts that don't complement each other. For example, a turbocharger without a proper ECU tune can harm the engine.
  • Overlooking Fueling Adjustments: When increasing power, ensure the fuel system can handle the increased demand.
  • Neglecting Transmission and Brakes: Higher power outputs put more strain on the transmission and brakes. Upgrade these components accordingly.
  • Poor Quality Parts: Using low-quality or incompatible parts can lead to reduced performance and engine damage.

Throttle Body Upgrades

Benefits of Throttle Body Upgrade for SkyActiv-G Engine:

  1. Increased Airflow: A larger throttle body can allow more air to enter the engine. More air, combined with the appropriate amount of fuel, can lead to more powerful combustion in the cylinders.
  2. Improved Throttle Response: An upgraded throttle body can enhance the responsiveness of the engine to throttle inputs. This means the engine can react more swiftly and precisely to accelerator pedal changes, improving the driving experience.
  3. Potential Power Gains: With increased and more efficient airflow, the engine can potentially produce more power. This is especially true if the throttle body upgrade is part of a series of modifications, such as a remap, exhaust upgrades, or an improved intake system.
  4. Better Engine Efficiency: A well-designed throttle body can improve the engine's air intake efficiency. This can sometimes translate to better fuel economy, as the engine can use air and fuel more effectively.

It's important to ensure that a throttle body upgrade is compatible with other modifications. For instance, if you've enhanced the engine's ability to expel exhaust gases (like with a high-flow exhaust system), a larger throttle body can complement this by improving air intake.

Simply installing a larger throttle body may not yield benefits on its own. The engine's control unit (ECU) might need to be re-tuned or re-mapped to take full advantage of the increased airflow especially if you've thrown other mods into the mix.

There's a point of diminishing returns with throttle body size. Too large a throttle body for the engine can actually hinder performance, particularly at lower RPMs where too much air can disrupt the air/fuel mixture.

Problems and issues to look out for on the SkyActiv-G

Preventative Measures and Maintenance

  • Regular Maintenance Following Mazda’s recommended service intervals is crucial. Regular oil changes, air filter replacements, and spark plug inspections can prevent many of the common issues.
  • Quality Fuel Using high-quality fuel and adhering to the recommended octane rating can reduce the risk of engine knocking and carbon build-up.
  • Timely Repairs Addressing small issues as they arise can prevent them from developing into larger, more costly problems.

Carbon Build-Up:

Being a direct injection engine, the SkyActiv-G can suffer from carbon build-up on the intake valves.

This is a common issue with many direct injection engines.

The buildup can lead to reduced engine performance and efficiency over time.

Oil Consumption

Some SkyActiv-G engines have been reported to consume oil at a higher rate than usual, especially as they age. Regular monitoring of oil levels and timely oil changes can help mitigate this issue.

Timing Chain Wear

Though not overly common, some SkyActiv-G engines have experienced premature timing chain wear.

A worn timing chain can lead to a variety of engine performance issues and, in severe cases, engine failure.

Engine Knocking

There have been instances of engine knocking, particularly in earlier versions of the engine. This can sometimes be due to issues with the fuel system or the use of lower-octane fuel than recommended.

Thermostat Failures

There have been reports of thermostat failures leading to overheating issues. Regular coolant system maintenance can help prevent or identify this issue early.

Idle Irregularities: Some drivers have noted irregularities in engine idle, such as rough idling or fluctuations in RPMs. This could be due to a variety of factors, including spark plug condition, air intake issues, or software needing an update.

Regular oil changes are vital on the SkyActiv-G, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your SkyActiv-G engine please join us in our friendly forum where you can discuss tuning options in more detail with our SkyActiv-G owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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We really like hearing from our readers, and hearing about which mods were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our SkyActiv-G guides and tips are kept up to date.

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