The Complete Guide to Auto Tuning

Tuning can take various forms and mean different things. For electric vehicles like the Tesla Model 3, owners can opt-in for lightweight body kits to improve aerodynamics and efficiency. Owners of ICE cars with a soft spot for speed may choose to remap the engine for enhanced performance. Modifications can be subtle and simple bolt-on additions or comprehensive and permanent fixes that completely transform your car.

Why Tune Your Car?

Although you can tune every car, not every engine has the same power thresholds. While some are only suitable for minor stock upgrades, others are the ideal starting point for a host of modifications. The end result is obvious. More force, better performance, improved handling, and a car that not only looks the part but also performs admirably on the highway or racetrack are all desirable qualities.

Which Cars Are Ripe for a Tune?

While even small-displacement diesel cars can have a simple ECU tune to add horsepower, automotive tuning with performance parts is best for engines with a lot to give. And these don’t necessarily have to have huge price tags or be recent models. Think VW Golf VI GTi, BMW 335i, or Ford Focus ST. These have sound internals to work with modifications that can add a bit more of everything.

Next are the rally-bred Subaru WRX STI and Mitsubishi Lancer Evo in almost any model version and production year. And finally, cars that don’t hide their intentions: the Honda Civic Type R, Toyota Supra, Nissan Skyline, and any Mercedes AMG, Audi S or RS, or BMW M car. Throw in a few sleepers of yesteryear (Volvo 740, Rover 75 V8, or Austin Mini Cooper are good examples), and there are even more choices to get your kicks.

How Tuning Is Done

Tuning involves adding aftermarket performance parts. The purpose is to push more air and fuel into the combustion chamber for a bigger bang. The parts are added in carefully thought-out stages, building performance figures with each addition.

Subtle changes free the stock engine of restrictions, with air intakes and exhaust parts the first to get a do-over. Next is optimising fuel delivery with changes to fueling and timing, and lastly, getting the last doses of available power with forced induction and swapping out the internals.

In general, there are three stages of automotive tuning, but these refer to different parts and modifications in different engines. You can access more power in engines built with a turbo in mind than say a naturally-aspirated engine. The limiting factors on overall power gains are durability, longevity, and, to a lesser extent, fuel use. You want something fast and fun to drive without breaking down after a few miles or draining your bank account while gulping down tanks of fuel.

Tuning Stages

Stage 1

ECU Remap

Uncovering concealed engine power can be done with a straightforward ECU remap. In all recent model vehicles, this is feasible. You can remap the car’s software to change fueling profiles, turbine boost pressure, or inlet and outlet valve timing. For better pulling and acceleration from a stop and higher rev power when gaining speed, a remapped automobile will have more available torque early on.

You’ll get these benefits while also lowering your fuel consumption and emissions. Remaps can be done on their own or used to balance out changes to the car after adding parts.

Air Intake Upgrade

If you want more performance, the engine needs to breathe. Gulping more air and pushing it at higher pressure or speed is the job of an upgraded air intake system. This is often the first modification across the board for different vehicles.

Revised air intake kits can remove restrictions to airflow to the engine and involve aftermarket filters, bigger and lighter airboxes, and a reworked tubing layout to optimise airflow. Heat is removed with a heat shield, meaning cooler air that’s richer in oxygen. You can follow this up with the addition of air scoops.

Aftermarket Exhausts

More combusted gases out mean getting in more air. Exhausts are the other side of the breathing coin. Their task is to remove higher volumes of spent gases at higher speeds. The aim is to prevent combusted gases from lingering in the tubing that keeps the engine from taking its next breath.

Removing these airflow restrictions is accomplished with wider tubing made of higher-quality materials that withstand increases in heat and pressure better than stock systems. The exhaust manifold, downpipes, mid-sections (such as catalytic converters and DFP filters in diesel cars), and mufflers and resonators used to adjust the exhaust sound are among the modified components.

Different exhaust setups result in varying power improvements. Wider tubing connects the catalytic converter to the tailpipes in cat-back systems, which is the absolute minimum requirement. Turbocharged and header-back systems produce more power. Tuners can also play with various exhaust systems, frequently removing constrictive original converters. Better materials also imply lesser weight and greater longevity, similar to air intakes.

Spark Plugs and Ignition Coils

Go for iridium-tipped spark plugs rated for higher heat in typical performance usage. Plug wires and coils capable of delivering higher voltage are the next logical step in combusting the more abundant fuel and air mix.

Stage 2

This is mostly the domain of fueling modifications and calls for additional mechanical expertise. Better intakes spooling in more air in stage 1 mods necessitate changes to how fuel is delivered for combustion and how much. Here, we see tuners choosing fuel injectors and fuel pumps that can deliver more gasoline at greater pressures and more fuel into the cylinder head, respectively. Find high-flow injectors that can do the job.

Understanding how does an injector pump work is crucial in order to find a solution for its improvement. It’s a precision component responsible for pressurizing fuel and delivering it in precise amounts to the injectors. Upgrading to a high-performance injector pump ensures consistent fuel delivery, crucial for optimizing combustion and unlocking additional power.

Timing changes refer to modifying camshaft profiles and lobes to create more overlap between engine cycles when opening and closing the intake and exhaust valves. This creates more power at higher engine speeds, allowing more air in from the intake valves.

For engines with turbines, such as the 2-litre EA888 in the Golf GTi, or the inline six N55 in dozens of BMW performance cars, power upgrades include bigger intercoolers, faster and bigger turbos able to spool more air, or twin turbo setups, with both a turbo and supercharger. Adding a boost controller and balancing the setup with an ECU tune can see engines gaining up to a 50 per cent bump in power. These are insane numbers, that unfortunately aren’t available for naturally-aspirated cars without complex mods done in stage 3.

Stage 3

Adding a turbo is one of the modifications in stage 3. It implies that you did all previously recommended mods and that the engine block and internals can handle the extra power. Choosing a base engine may be the hardest part of getting this right.

There are revisions to exhaust manifolds and headers and the addition of charge pipes. There also needs to be a reduction in the compression ratio, using a revised and shorter piston and connecting rod combos that create a shorter engine stroke to handle the high boost pressure from the turbine. Also, you need to rework cylinder heads and strengthen gaskets.

For engines with forced induction, mods continue where they left off in stage 2. It can mean replacing the stock turbo with a twin-scrolling unit, with two separate turbines calibrated to pull air in at both low and high revs, effectively eliminating turbo lag. Engines with cast internals ditch these for forged pistons and conrods.

In addition, there are dozens of ways to optimise cranks in handling the added power, such as nitriding and cryogenics, effectively strengthening the metal against the rise in torsional and bending loads with each cycle. Again, these are complicated mods involving a lot of calculations to get everything right.

What Can a Car Tune Bring?

The short answer is more horsepower and torque, better power delivery throughout the rev range (no dead spots), and a more responsive vehicle. Numbers can vary depending on the engine and the types of modifications and tuning stages.

Tuning can be a fun hobby to the point that it’s done carefully and within realistic expectations. The best part is that you get a faster car for a lot less than what’s currently available.