Chip tuning

Chip tuning is changing or modifying an erasable programmable read only memory chip in an automobile's or other vehicles electronic control unit (ECU) to achieve superior performance, whether it be more power, cleaner emissions, or better fuel efficiency. Engine manufacturers generally use a conservative electronic control unit map to allow for individual engine variations, as well as infrequent servicing and poor-quality fuel. Vehicles with a remapped electronic control unit may be more sensitive to fuel quality and service schedules.

This was done with early engine computers in the 1980s and 1990s, and it evolved over time with the technology that was available. Initially, it was fairly difficult to do, requiring desoldering the old non-programmable ROM chip from the ECU and replacing it with an EPROM chip that was programmed in hex using software on a computer. This was extremely time consuming and involved, and only certain people could understand how to tune an engine in hex, so software was developed to interface with the chips and provide a Graphical User Interface (GUI) for the user to view data like engine fuel maps to put onto the EPROM or later EEPROM chips.

Some vehicles, like the Chevrolet Corvette (C4) had a port where you could place your own chip into the ECU, so it didn't require desoldering the old chip. Chips started to be sold pre-programmed for certain vehicles and could be plugged into a port, if the ECU came with it, or into a dip socket that has to be soldered onto the board, depending on the manufacturer. Cars like the Honda Civic in the 1990s was known for being easy to tune and get a lot of power, even with a turbocharger, so many ECU's were tuned in this way.

Today, the term chip tuning can be misleading, as people will often use it to describe ECU tuning that does not involve swapping the chip.