How Does a Performance Chip Work?

by Tony Breedlove


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Purpose of the Factory Chip

Modern car engines are controlled by a computer. These computers have a “chip” that tells the computer when and how to adjust your car’s timing, its fuel-to-air ratio, turbo boost and other things. Since automobile manufacturers must be competitive in fuel consumption, and comply with emissions and other regulations, they often leave a good bit of outright performance on the table when it comes to these settings.

Purpose of the Performance Chip

Performance chips, sometimes called superchips, are aftermarket chips that adjust these parameters, often increasing engine power and torque. Some performance chip makers claim their chips will increase gasoline engine power by up to 35 horsepower and beyond, and even more in a turbocharged or diesel engine. These engines are often heavily constrained by the amount of boost the turbos are permitted to produce, or how much fuel gets injected. It's not uncommon for a performance tune to up gas turbocharged engine power by 50 to 75 horses, and diesels by 100 horsepower or more.

How Performance Chips Operate

The factory chip in an automobile contains something referred to a "lookup table." The lookup table contains data that tell the engine how to respond under various circumstances. For instance, if you are driving down the highway going 50 miles per hour and you quickly press the gas petal all the way to the floor, the computer will detect this and ask the chip what to do. The chip will refer to its lookup table and tell the computer how much gas to send to your engine, how and when to shift an automatic car into a lower gear, how to adjust the timing and how much turbo boost to provide, if your car is equipped with a turbo charger. In a factory chip, all of these parameters are dictated by the car manufacturer for its own purposes. When you put a performance chip in, this changes the lookup table and adjusts the parameters to give you the most performance without regard to fuel economy, emissions and other performance-reducing constraints.

Installation and Cost

Performance chips, or superchips, are very easy to install; usually you remove a cover under the dashboard and simply pull the factory chip out and replace it with the performance chip. These chips are specifically programmed for the model, make and engine type of each car and are readily obtained over the Internet. Major manufacturers are Unitronic, REVO, GIAC and APR, and the chips usually cost around $600. For the cost conscious, there are some chips costing less than $300. If you are considering installing a performance chip in your car, thoroughly research the available chips and make a well-informed selection because all chips are not equal.

When a "Chip" Isn't

These days, most vehicles don't use removable "chips," as they did back in the 1980s and 1990s. Prior to the introduction of OBD-II in 1996, the use of removable "PROM" chips, which contained all of the computer's lookup tables and programming, was common. The original PROM chips were single-use only, meaning that once they were programmed, they could never be erased and reprogrammed. The only way to change programming was to physically unplug the old chip and plug in a new one. Integrated re-programmable memory chips like those in your home computer have since replaced those. So, modern "power chips" are usually just mini computers that plug into your diagnostic port and hack the original software to change the parameters and lookup tables. Perhaps it's a case of nostalgia, but many still refer to these plug-in tuners as "chips."

Things to Consider

While performance chips can increase performance, there are downsides. Installing a performance chip in your car will void your warranty. Also, you should expect a reduction in fuel economy and an increase in emissions. If your state tests for emissions, installing a performance chip could increase your car emissions enough that it causes you to fail state emissions testing. Also, performance chips can sometimes increase the cost of your car insurance coverage. Additionally, if the new chip is not programmed properly, you could experience reduced engine life. However, the upsides are often significantly increased power and torque and increased engine response.

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