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Maximising performance

The world of engine tuning has brought a certain breed of humans to group together. Power-hungry individuals that are usually found watching 1320 Video on YouTube and building and breaking engines to rebuild them stronger. Engine tuning is where precision engineering meets blistering performance, turning ordinary cars into the craziest machines capable of exceeding everyone’s expectations.

It’s a competitive sport, who can tune a car, reliably with significant gains over the manufacturer’s claimed horsepower and torque figures. This comprehensive guide will cover more than the basics. You should understand the process of remapping and how your tuner extracts more performance from your engine.

chrome carbureted V8 engine tuning
© Tim Mossholder

A brief history of engine tuning

The concept of engine tuning goes back to the earliest days of the automobile when enthusiasts wanted to push the boundaries of what their engines could achieve. Initially, any alterations were mechanical, involving adjustments to carburettors, ignition timing, and exhaust systems to extract more power.

As technology advanced, particularly with the introduction of electronic fuel injection (EFI) and computer-controlled engines, tuning evolved into a more refined process, combining a mechanical operation with software engineering.

This transition from mechanical to digital tuning shows the automotive industry’s broader technological advancements, showing how innovation drives the endless pursuit of efficiency improvement.

Engine tuning basics

Engine tuning is the process of modifying a car’s engine to improve performance and efficiency. The basics involve adjusting certain parameters within the car’s Engine Control Unit (ECU), which manages the engine’s fuel and air mixture, ignition timing and boost pressure in turbocharged and supercharged applications.

First came chip tuning, which was the process of removing a memory chip and reprograming it with a new file.

The modern way of replacing the file on the ECU is through remapping; directly connecting to the ECU. Much faster if you’re making a lot of file revisions!

Simple tuners may only remap the ECU for better throttle response and increased horsepower, while more advanced tuning can include hardware upgrades to components like the intake and exhaust systems, installing a bigger turbocharger, or even making internal engine modifications. It’s a way to tailor a car’s performance to the owner’s preferences, whether for smoother driving, better fuel economy, or maximum power output.

tuning fork scott hilzinger haltech engine tuning mighty car mods
© Tuning Fork via Facebook

Understanding OEM tuning

It’s important to remember that the concept of engine tuning isn’t solely the domain of aftermarket modifications. Original Equipment Manufacturers (OEMs) also use engine tuners to design factory tunes that strike a balance between performance, fuel economy, emissions compliance, and long-term reliability.

These factory tunes undergo rigorous testing under various conditions to ensure they meet stringent standards. The work of OEM engine tuners exemplifies how even vehicles straight from the dealership have been optimised for a general set of criteria, laying a solid foundation upon which aftermarket tuning can build to further specialise and enhance a vehicle’s performance.

ECU’s and EFI explained

ECU’s and Electronic Fuel Injection (EFI) systems revolutionised the landscape of automotive tuning. These technological innovations control a vehicle’s internal combustion process with exceptional accuracy, offering tuners the ability to optimise engine performance through engine tuning software. Digitalising the combustion process enables us to unlock significant gains in power output, fuel efficiency, and throttle responsiveness.

EFI was a groundbreaking innovation because it allows for precise control over fuel delivery, dramatically improving engine performance and efficiency. This precision ensures optimal combustion, resulting in better fuel economy, smoother operation, and increased power output compared to older carburetted systems.

engine tuner using laptop with link ECU tuning software
© Simon Cousins

How engine tuning works

Engine tuning works by adjusting the parameters within the ECU that control how an engine operates, to improve performance, efficiency, or both. The process can involve both hardware modifications and software changes to the ECU.

Multiple factors dictate the outcome of your power when it comes to hardware. To keep it simple, I’ll not go into specifics, but when hardware relating to the engine is changed, you will need to recalibrate, remap the ECU to reap the benefits of increased performance.

An engine tune is like a tailored suit; if you gain or lose weight, the suit isn’t going to fit properly. Custom ECU tunes are like getting a suit made to fit you perfectly.

Here’s a synopsis of how it typically works:

ECU remapping and chip tuning

Modern engines are controlled by an ECU, which is essentially a computer that dictates how the engine functions. Remapping or chip tuning involves altering the software program or “map” that controls engine performance. By changing the parameters within the ECU, such as fuel injection timing, air-to-fuel ratio, and ignition timing, tuners can make the engine produce more power, operate more efficiently, or achieve a balance of both.

The remap can be customised to a driver’s specific needs, whether it’s for improved fuel efficiency, increased torque and horsepower, or a smoother power delivery.

Adjusting the air and fuel mixture

More power can be generated by adjusting the air-to-fuel ratio, especially in turbocharged engines. For performance tuning with petrol engines, the aim is to allow more fuel and air into the combustion chamber, as a richer mixture (more fuel) can produce more power when ignited.

However, this needs to be done carefully to avoid running too rich or too lean, either of which can cause engine damage.

Achieving optimal engine performance and fuel efficiency isn’t a one-size-fits-all process. Contrary to the notion that the leanest fuel mixture yields the best power, the ideal AFR varies by engine type and fuel. Similarly, peak fuel economy doesn’t always occur at the stoichiometric point; adjustments are made to balance efficiency with emissions, especially as leaner petrol mixtures can elevate NOx emissions. It’s a balancing act, tailored to each vehicle’s specifics.

Fitting or upgrading a turbocharger or supercharger

Forced Induction: Engines can be tuned to produce more power with the addition of or modifications to a turbocharger or supercharger. These devices force more air into the combustion chamber, increasing the amount of fuel that can be burned and thus increasing power.

Tuning with forced induction involves adjusting the boost pressure of these devices to increase power output. This often requires supporting modifications to handle the increased air and fuel flow, such as upgrading the fuel injection system or replacing engine internals with upgraded components.

Modifying intake and exhaust systems

There is more to it than this but here’s the basic theory: By improving the engine’s intake system with less restrictive air filters or larger intake manifolds, more air can be delivered to the engine, which can be used to burn more fuel and produce more power.

Modifying the exhaust system with larger pipes or high-flow catalytic converters reduces backpressure, allowing exhaust gases to exit the engine with less resistance. This can improve engine efficiency and power.

Upgrading engine components

Engine components such as pistons, camshafts, and valves can be upgraded to stronger, lighter and lubrication-friendly versions to handle increased power and improve engine performance. These modifications often go hand-in-hand with other tuning upgrades to ensure the engine can safely and effectively use the increased power.

Cooling systems

Higher-performance engines generate more heat, so improving the cooling system is often an essential part of engine tuning for sustained use. This can involve installing larger radiators, more efficient water pumps, or other cooling systems for turbocharged engines, like intercoolers.

Higher octane fuel

Engine tuners can usually implement more aggressive ignition timing safely due to the knock-prevention properties of higher octane fuels, enhancing performance and efficiency. This is particularly beneficial for engines with forced induction and higher compression ratios, enabling them to operate at their full potential without the risk of engine damage.

Garrett Turbo Turbocharger EA888 TFSI VAG
© Simon Cousins

Navigating the "stages" of engine tuning

The journey through engine tuning is often categorised into stages, each representing a level of enhancement and commitment. It’s not an official hierarchy for every car, each will vary slightly, but it’s generally how tuners will refer to each level of a cars modification “stage” to be able to market expected power gains for customers to see.

Let me go through the most common stages of remapping:

Stage 1

Stage 1 focuses on software modifications alongside minor hardware tweaks, such as air intake and minimal exhaust upgrades. This is where basic performance improvements are made without altering the engine’s core architecture.

Stage 2

This is where more substantial hardware modifications start. This may include the fitting of larger downpipes, enhancements to the exhaust system, and potentially turbocharger accessory upgrades, such as turbo inlet pipes and an intercooler. In some cases, I’d bank on upgrading your clutch and flywheel or getting a transmission map tweaked too.

This is usually a great area to remain in if you want to retain drivability and keep it relatively simple.

Stage 3

Don’t tell the missus, the really expensive modifications start here. Significant modifications such as the engine’s internals, turbocharger, and fuel delivery mechanisms. This stage is where, in some cases, you begin to push the OEM components to the limit. You have to do your research or be prepared to have a few items break in the process. This helps me with my transition into my next point.

JBM performance engine tuning on MK5 Golf GTI
© Simon Cousins

Acknowledging the risks of engine tuning

I know how easy it is to get carried away with modifying your car, but you must recognise the potential risks involved in engine tuning.

Modifications can increase the strain on an engine’s components, potentially leading to premature wear or even failure. Furthermore, if your car is still under warranty, significant alterations may render it void.

Certain modifications to your exhaust or other emissions devices might mean your car wouldn’t comply with local emissions regulations, so you’ll be sent for a vehicle inspection to ensure your car is road-legal. The worst-case scenario would be the potential for legal and financial repercussions. Use reputable professionals to mitigate risks, at least if you’re not sure about something, your tuner should be able to point you in the right direction.

One thing I would always recommend is that you choose a reputable tuner who always performs a pre-tuning inspection before running the car on the dyno. This will reduce the chances of any damage being caused during tuning or even 6 months into the future. It is very important that the car doesn’t have any faults when tuning. Having a clean slate will ensure you end up with a reliable tune and optimal performance.

Google search: Engine tuning near me

Engine tuning is a complex and technical process that varies widely depending on the vehicle, the desired outcomes, and the extent of the modifications. It requires a thorough understanding of engine mechanics and computer-controlled engine management systems. As such, it’s often best left to professionals who can ensure the modifications improve performance without compromising the engine’s reliability or longevity.

This article was put together to educate and inspire you, positioning engine tuning as a gateway to a more fulfilling driving experience, and its role in enhancing vehicle performance.

Tuning is not just about increasing power; it’s about refining the driving experience, making each journey more exhilarating than before.

Lamborghini Gallardo White with big twin turbos
© Simon Cousins


Can you manually tune a car?

In a word, yes. But that would apply to older engines, known as mechanical tuning, which is a delicate art that requires expert knowledge and the right tools. One wrong move and you could turn your pride and joy into a very expensive paperweight. You can install and modify components to lie to the ECU to get a desired outcome, but I wouldn’t ever suggest doing so.

Can you tune a normal engine?

Absolutely. Engine tuning isn’t just for high-performance machines; even everyday commuters can benefit from a little extra kick. A stage 1 or 2 tune would make your commute a whole lot more fun.

Can you tune a car without an aftermarket ECU?

While aftermarket ECUs offer greater flexibility and control, it’s still possible to achieve noticeable gains with factory ECUs through remapping. In most cases, you won’t need an aftermarket ECU. Just remember, it’s all about finding the right balance between performance and reliability. If you want to retain the ability to still use your factory features, you’ll want to find a compatible ECU, or you’ll want to keep the factory ECU.

How much does engine tuning cost?

The cost of engine tuning can vary widely based on the type of tune, the specific vehicle, and the desired performance outcomes. Basic ECU remapping can start from a few hundred pounds or dollars, while comprehensive tuning that includes hardware changes like upgraded turbochargers, exhaust systems, and other performance parts can escalate to several thousand. Always consult with a reputable tuning professional to get an accurate quote for your vehicle.

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