Computer-Chip Tuning

Modern Electronically Fuel Injected (EFI) vehicles couldn’t do what they do as well as they do it if it were not for on-board computers. This is an indisputable fact. The ability to deliver superb driveability and performance with excellent fuel economy and low emissions is mainly possible because of the use of vehicle computers. As the vehicle manufacturers (OEMs) have continued to improve the technology of their vehicles, the aftermarket has benefitted as well. New vehicles are far more "tunable" than older onesbecause of the vast flexibility and quick response of modern electronic control systems. This has helped to actually make it easier to dial in modifications after they are installed. While this capability was initially thought of as black magic by many, it has become relatively commonplace due to the availability of recalibrated computer chips and similar devices. For older vehicles, it is easier to make changes without worrying about increased liabilities down the road – their first generation onboard-diagnostic (OBD) systems arenot sophisticated or sensitive enough to detect most changes nor are they able tomonitor the vehicle as often as the new ones do. The OEMs generally used easily removable snap-in computer chips in the older OBD systems which are relatively easy to remove, unscramble and recalibrate/reprogram as needed to allow modifications to work properly.

Numerous companies currently sell recalibrated chips for a variety of applications which allow you to install such things as headers, turbochargers, camshafts or other such modifications and still meet emissions requirements while getting the most out of the changes you made. Most of the chips which are sold for street use have even been granted California Air Resources Board (CARB) Executive Order (EO) numbers – signifying they have demonstrated that they don’t increase emissions when used as intended. Even in cases where the computer chip is "potted" or soldered to the computer board, changes are possible since other technologies can still be used to change the vehicle calibration.

There are currently several ways to do this. One of the easiest ways is' to add another chip which is remov-able and can be programmed separately with a new calibration. By properly integrating the vehicle computer’s chip, the data from the add-on chip will overrule/replace the vehicle chip’s data and thus change the commands coming from it (injector pulsewidth, ignition timing, etc.).

This essentially recalibrates the vehicle computer’s chip without having to touch it; however, you still have to have a very thorough understanding of how the computer system works – what its overall strategy is and so on. You also need to know where and how to "insert" your new data into the data stream of the vehicle computer chip so it is used instead of what is there from the factory.

Nonetheless, several companies have figured these things out and offer products which do just that. One example of how this is done is through the use of a "daughter board" which is actually installed in the vehicle computer itself. This extra circuit board contains a separate chip which has the new calibration data. The extra board is permanently soldered onto the vehicle computer’s main circuit board as needed to intercept and transmit the appropriate signals/data to the rest of the vehicle. In some cases, the extra chip can be mounted externally to the computer itself by interfacing via a service port or through the main wiring harness going out to the vehicle.

The same effect could also be obtained by removing the vehicle computer’s chip and then recalibrat-ing and reinstalling it, similar to what was mentioned earlier. This process is considerably more difficult when the chip does not snap in; but it’s still feasible. Some manufacturers do this at their facility where they have the necessary equipment to remove the protective "potting" which surrounds the chip so they can then "desolder" the chip from the circuit board and reprogram it. It is then resoldered onto the circuit board and the entire board (or computer) is then sold as a drop in replacement which allows your modifications to work properly.

Obviously, this can be more expensive than just adding another circuit board and chip but it may be necessary in some cases due to space or thermal considerations, etc. This should become less necessary with newer vehicles. Later vehicle models, which conform to the newer OBD system regulations (called OBD-II, which is mandated by the EPA) use non-removable chips called EEPROMs and Flash EEPROMs. These systems don’t need to have the chips removed from the circuit board since they can be reprogrammed electrically if you have the knowledge and the equipment to do so. This is one of the reasons the OEMs went to this technology instead of having to stock a bunch of different computers with different calibrations in them, the OEMS now only have to stock a few generic configurations of the "hardware" since the appropriate "software" (the correct calibration) can be downloaded as needed just before the computer is put in the vehicle. It saves a lot of money for both the OEMs and their dealers plus it reduces the chance of not having the right "part" on hand.

Unfortunately, while there is a good chance that the OEMs will allow other "authorized" parties besides their dealers to reprogram these new chips, only downloading of OEM-approved calibrations will be allowed. Currently, "custom" calibrations for optimization of performance parts, or for improved performance in general, will not be supported by the OEMs or their dealers. This is something that is being discussed, but the OEMs are not very receptive to the idea at the moment.

So far, only one product has been developed which claims to be able to alter the OEM calibration when these new types of chips are used. Using a strategy very similar to what the OEM/dealership equipment uses, this product essentially swaps the new calibration it has stored in an internal chip for the calibration in the vehicle computer’s chip. After you use it, the vehicle has the after-market calibration and the programmer has the original vehicle calibration. This way, you can go back to the original at any time, or as many times, as you’d like.

Besides the various technologies discussed above which allow you to install somebody else's new calibration, there are also products currently available which, within limits, allow you to do your own recalibrating. These products basically take two forms: products which directly recalibrate the vehicle computer chip and products which change the way the vehicle functions without changing the contents of the chip. The former range from software packages which you install on your personal computer to stand-alone devices that do everything themselves.

The PC-based software packages generally require that you also buy an attachment which actually does the reprogramming based on the commands it receives from the PC via a serial port. These "PROM Burners" are easy to find for the older style snap-in chips since these chips were basically the same as the chips used in many other electronic devices. The software packages basically made these generic prom burners intelligent enough to know where in the chip to go to alter the data, based on your inputs. They also made this data readable in an organized format so you know what areas of the chip to make changes in.

Similarly, there are also currently products on the market which can best be thought of as "translators". They are sometimes also referred to as "piggy-back" devices since they generally attach to the vehicle computer between the computer itself and the vehicle’s wiring harness. These products differ from the chip modules discussed earlier in that they intercept the inputs and/or outputs to the vehicle computer and modify them based on input you’ve provided, usually via a key-pad or laptop PC.

They offer variable calibration capability as opposed to the single calibration that comes in the chip or module. These products essentially "fool" the vehicle computer into thinking that operating conditions are different than they really are or they simply provide a modified output signal for such things as ignition timing or fuel injection, etc. based on the conditions and changes you select.

Therefore, the onus is on you to make sure you provide the right inputs to make an improvement. These types of devices generally offer less range for making changes and they also tend to offer fewer variables to change. This is offset, however, by them being generally easier to use and by their offering the capability to program additional outputs such as timers relays for pumps, etc. Some of the more common uses include turning on nitrous oxide systems and/or auxiliary fuel pumps, etc. when a certain operating condition is reached. Some even offer the capability of controlling additional fuel injectors. Many of these units also offer various degrees of data acquisition capability so you can record how the vehicle was operating at a given point in time. This is particularly useful when trying to dial in a calibration on the road. The potential for these types of products to be successfully adapted for use with the new types of computer chips is probably the greatest although none has yet been marketed.

Of course, you still have to do extensive dynamometer and/or vehicle testing in any case to develop the new calibration; you can’t just go in randomly and change your ignition timing and fuel delivery, etc.– and expect things to work out.

Whether or not this will be possible with the new types of chips remains to be seen; plenty of people are working on it to be sure. The key is not so much being able to make the vehicle behave differently as much as it is being able to do so and still be compatible with the OBD/OBD-II system and meet emis-sions.

If history is any guide, aftermarket manufacturers will figure out ways to get around these obstacles and give people options for modifying their vehicles. While it most certainly is "goodbye" for the current level of chip technology which became fairly easy to work with, it is also "hello" to the new EEPROMs and Flash EEPROMS which may eventually prove to be even better yet. The vehicle computer systems that they’re installed in clearly are an improvement over the previous level of technology.

While it may take a while to figure them out, new products will likely be developed for them just like they were for the ones before them. As long as CARB and EPA don’t ban such products outright, we should have something to look forward to some day.