New Chip and Tuners FAQ

Written by ncc386

Your powertrain control module (PCM) is the computer that controls nearly every aspect of your vehicle. The factory PCM calibration is a compromise of performance, fuel economy, and emissions. For years, this calibration was used as the foundation for custom tuning. Since there is only so far you can go with the stock calibration, there were never any sizeable power gains to be had in stock or near-stock applications. This is the reason why most people believe a custom tune is not necessary until a radical change, such as a power-adder, has been made. In their defense, they were correct at that time.

With the recent advancement of electronic fuel injection tuning methods and technologies, it is now possible to literally rewrite the factory calibration from scratch. Your PCM has several banks of memory that store the original calibration data as well as the original tune. Keep in mind that these are two completely separate concepts. Until now, only the tune was changeable. The major advantage to recalibration over traditional dyno tuning is that the PCM can be reprogrammed to understand the physical changes that have been made to it and the parameters required to accurately control them.

For example, if a 2000 GT has a blower, the stock PCM has no idea there is a blower installed. Through the MAF, the PCM gathers data to calculate how much air is being ingested and, in turn, decide on fuel and spark based on several tables where load is a factor. A stock PCM would have readings that went off the scale. This causes the load calculation to invert, almost as if it believed the car was slowing down. The PCM responds with incorrect timing and fuel adjustments. Previous EFI tuning involved flat timing changes by RPM that effectively removed load from the equation. The downside to this method is that a human is using a percentage to adjust fuel, timing is the same regardless of load, and when the weather changes so does the tune. All this leads to significantly lost performance and possible pinging with major temperature deviations.

Changing the MAF to an OEM-compliant unit that has the resolution to see the increased airflow, rewriting all spark and fuel tables to record greater than 100% load, and following with a standard dyno tune is how recalibration is done on this vehicle. There are no parameters that are rigged to work, no percentages guesstimated by a human, no flat spark. The car came with 19# injectors. Why lie to the PCM for 42# injectors when you can just describe how they work to it? Everything is rewritten from scratch and designed for the PCM to once again take the reigns and make all self-adjustment decisions on the fly.

In the end, what you have is a vehicle that typically makes 6%-9% more horsepower than before, can self-adjust using its factory sensors when weather conditions change, and can actually see when it's in boost due to the expanded spark and fuel tables that now see load figures greater than 100%. What you have is a car that may put down 390-420rwhp instead of 360-390rwhp.

Through recalibration, the three-way compromise can also be adjusted or removed. This gives rise to stock cars able to put down positive numbers on the dyno instead of random gains or, in many cases, losses. It is not impossible to see 10-15rwhp gains on a completely recalibrated 2004 GT when the PCM no longer has to keep itself in balance with emissions and fuel economy. It is also not uncommon for these vehicles to maintain good gas mileage and pass emissions tests regardless. The motor is simply that efficient.

Two of the most popular EFI tuning companies are SCT and Diablosport. Although the SCT software is the only one to enable recalibration presently, the Diablosport software is not far behind and is advanced enough to provide similar results. Both companies provide their products through a dealer network. As the end-user, you would be looking to a motorsports shop that utilizes these technologies in order to have your car tuned.

At the moment, there are two ways of having your car tuned: chips and flashers. Both companies offer these methods, however the differences between them are purely aesthetical. A chip temporarily overrides the parameters in certain banks of the PCM while the flasher permanently overwrites them. Whether or not one particular company offers more powerful software for one application or another is their prerogative. A modern four-bank chip is physically capable of completely taking over the PCM's functions just as much as a flash. There are only certain circumstances when a flash is necessary; some PCMs come from the factory with their expansion port disabled. If you have never installed a chip before, you may prefer to buy a flasher. Flashers plug into the diagnostic port under the dash and are removed after the programming process is complete. Chips require you to uninstall your PCM, disassemble the case, and prep the board before installation can begin. It's about 15 minutes of annoyance for a professional and typically 30 minutes of fear and uncertainty for the newcomer.

Q: Will there be a big performance gain if I buy a chip or flasher?

A: This depends entirely on the skill and experience of the person programming the chip. Let's not beat around the bush here. It doesn't matter how advanced the tuning software is; the software is simply a tool. It still takes a skilled hand to work with it effectively.

Code’s Info

By far, SCT is the best software out there. They utilize the Ford software that allows the EEC/ECU/PCM (they’re all abbreviations for the same thing) to automatically correct itself and optimize the a/f ratio. The result is a safer and higher horsepowered vehicle with the ability to learn when you modify it. As you mod the car, the EEC will learn what mod you did and adjust the a/f to gain maximum horsepower.