Engine Tuning 101: what you need to know

While the term “tuning” has been around since even before the days of The Fast and the Furious, it has taken on a new meaning in the modern era of car modification. Back in the early 2000’s tuning was used as a blanket term to describe all different sorts of modifications to a car. Installing a new exhaust, intake, turbo kit or even suspension all fell under the umbrella of tuning your car.

The Fast and the Furious raised public interest in tuning

While the term is still sparsely used in that way today, its definition has mostly evolved into something far more specific. Nowadays, when someone mentions tuning, they’re usually referring to modifying a car’s engine software in order to make it more powerful and thus faster. This means that modern tuning, in many cases, requires absolutely no hardware modifications: all you do is adjust the software and your car becomes faster. This happens through a variety of different methods which we’re about to discuss along with some other details to help you understand exactly how tuning works. 

How does tuning make a car faster? 

It may come as a surprise to some that you don’t need to install some raucous exhaust system and aftermarket forced induction kit to make your car faster, but tuning makes that possible. This is because all modern cars’ engines are controlled by a computer, known as the ECU, or engine control unit. The ECU tells your car’s engine how to run: it will tell it how much fuel to use, how much air that fuel should be mixed with, how to time when the spark plug fires, and if your car has a turbocharger, how much to open the waste gate and thus how much compressed air (i.e. boost) to shove into the cylinders. 

You don’t necessarily need to replace physical parts to increase performance.

In the vast majority of cars, these parameters are set rather conservatively in order to maximize fuel economy and extend the longevity of the engine. However, if you prefer to have some more grunt rather than get a few extra miles per tank, you can use a tune to adjust these parameters according to those preferences. For instance, a tune may tell your car to adjust the ignition timing in order to increase overall power output, or it may tell it to add some more boost for the same purpose. In many cases though, it will do both of these things, along with a host of other adjustments, in order to give your engine software a total overhaul in an effort to make your car more powerful. 

How much power does a tune really add? 

The degree to which a tune can actually increase your car’s performance is largely dependent on what type of car you drive. More specifically, it depends on what type of engine your car has and whether or not it is naturally aspirated or equipped with a turbocharger. Generally speaking, turbocharged cars stand to benefit far more from a tune than a naturally aspirated car. This is because tunes can tell the turbo to compress more air, and just a few extra psi of compressed air can make a huge difference. Conversely, naturally aspirated cars do not have this luxury, and must rely on ignition timing and fueling in order to increase power. Naturally aspirated cars can still be tuned, but they will not benefit as much as a turbocharged car will from a tune alone. 

Generally speaking, turbocharged cars can expect to gain between 10% and 25% more horsepower than stock from just a tune, while naturally aspirated cars can expect to gain somewhere between 5% and 15% more power from a tune alone. Cars with engines that are larger and more powerful from the factory will fall on the higher end of those spectrums, and cars whose engines are smaller and less powerful from the factory will fall on the lower end of those spectrums. 

Different tuning methods

There are two distinctly different ways to go about tuning your car. The first and often least expensive method is called a piggyback tune. Piggyback tunes are small modules that plug into one or more sensors in your car’s engine bay. They will plug into a sensor, and then effectively “trick” the car into thinking that it isn’t making as much power as it should, which will, very basically, force the car to make more power.

An example of how this can work is best given in the instance of a turbocharged car. Turbocharged cars have a sensor call the MAP sensor, which stands for mass air pressure. This is the sensor responsible for measuring and reporting to the ECU how much boost the car is making. A piggyback tune will plug into this sensor and manipulate the signal that it sends to the ECU, causing the ECU to think that the car is making less boost than it actually is. In order to compensate, the ECU will tell the car to make more boost, thus making it more powerful. 

The next and in most cases preferred tuning method is known as a flash tune. Flash tunes work by completely reprogramming your car’s ECU, and do not rely on having an actual module plugged into any sensors in your engine bay. There are two different ways to go about flash tuning your car, and which method you’ll use will simply depend on what products aftermarket companies can offer for your car.

The first method is most often just referred to as a flash tune, and this involves plugging a computer into your OBDII sensor and loading a new software map into your ECU. This can be either done by yourself at home or by a shop, again depending on what is available for your specific car.

A flash tune is done with a computer, and can be DIY, or done by a shop

The second method is referred to as a bench tune. This involves removing the ECU from your car, mailing it out to a tuning company where they will load the software map onto the ECU, and then send the ECU back to you for reinstallation. Neither of these methods is preferable to the other for any reasons other than convenience, and which you choose will largely depend on what companies are offering for your car’s platform.

Pros and cons of tuning your car

Upon first inspection, tuning can sound like quite an attractive proposition: relatively minimal effort, and in many cases, a substantially quicker car. However, it’s certainly not for everyone, and the following pros and cons should be weighed extensively before you decide to run out and tune your car. 

Pros of tuning your car

  • More power and torque
  • Quicker acceleration
  • Sharper driving dynamics (increased throttle response, more intelligent shifting etc.)

Cons of tuning your car

  • Decreased fuel economy (in most cases) 
  • Increased stress and wear on your engine 
  • Potential to void your car’s warranty if it has one

We’ve already thoroughly fleshed out the pros of tuning, so let’s take a second to go into some more details about the cons. The first is that, in most cases, your fuel economy will decrease as a result of the adjusted parameters requiring more fuel in order to run optimally. The next con is a big one, and this is that tuning can introduce more stress and wear on your engine. The degree to which this should be of concern is almost entirely dependent on what company you decide to use to tune your car. Some companies design fantastically reliable and safe tunes, and others do just the opposite.

For example, I had my previous car tuned for almost 20k miles, and oil analysis showed that the engine was wearing less than what is normally seen on stock examples of the same engine. I attribute this to proper maintenance and choosing a well-designed tune. So, it’s important to do some research on this topic and decide for yourself which company is the best for your car. Finally, we have the issue of warranties, which can, in many cases, be nearly completely voided by a tune. While the warranty company can’t outright void your warranty because you tuned your car, you can bet that if you have any drivetrain related issue, they will blame it on the tune and thus not cover the repair. 

Final thoughts: to tune or not to tune?

As will be the case with just about any car-related modification, the decision on whether or not you should do it will always depend on your preferences. If you want a quicker car, and you’re OK with a few less MPG, the potential for more wear on your engine, and giving the warranty company the opportunity to avoid covering your repairs, then tuning may be for you. However, if you prioritize a turn-key, no worries motoring experience, you may want to stick to the stock configuration, and save up for a quicker car when it’s time for new wheels next time. 

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