An aftermarket ECU / ECM / PCM is one of the most versatile and powerful items in the serious tuner’s toolbox. Aftermarket computer tuning allows for precise and custom computer controls over engine conditions and processes. If you’re serious about high-tech engine tuning, you need to know exactly how ECU tuning works, who needs an aftermarket engine computer and why, and which upgrade is right for which situation.
Think of your engine’s computer as a telephone operator connecting calls. A sensor calls for more fuel, so the ECU connects it to talk to the injectors, increasing the duration or intensity of the fuel stream. Another sensor may call recommending that the ignition timing be changed in a specific way, so the ECU connects it to the coil packs and so on. Every telephone operator relies on a list of extensions to make sure that calls are processed correctly. Likewise, for every piece of information (or call) that the ECU receives, it refers to a table of information to decide what action to take.
Every car comes from the factory with the ECU tuned to work well with stock equipment, under the most common driving conditions with an average driver behind the wheel. That means that any car whose engine is modified in any way may be sending confusing signals to the ECU, resulting in reduced performance. The more modifications, the greater the potential gain by changing the ECU.
On a basic level, ECU tuning is actually a relatively simple process. Simply put, it is the process of altering the background information contained in the engine computer to change the way that the vehicle performs. The more changes that are made, the more complex the process becomes. ECU tuning helps your car to run better by making sure that the computer has the correct information about what is happening in your engine, including the change in engine properties resulting from modifications.
There are a few common options when it comes to altering the performance of your stock ECU. Depending on your level of expertise and commitment, there are different options you might consider.
One of the best options that have become available is custom ECU reprogramming. The process is fairly easy to understand and complete. You supply the reprogramming company with information about your car and what modifications are installed, and they reprogram an ECU with a more optimized data table. Companies like HONDATA (a popular reprogramming service for Honda ECU’s) may also offer custom on-site tuning of ECU’s as well.
The next step up is a “piggyback” ECU that works with your engine’s computer. Piggyback ECUs are designed to interface with the stock computer and help interpret and redirect information. This type of setup offers greater flexibility and control for the experienced tuner.
For the most demanding and experienced tuner, there are fully independent engine management systems available like those offered by HALTECH. These offer the most adjustability and precise control, but are the most difficult and complex to install and understand.
“Chipping” an ECU is one of the most poorly understood (and potentially damaging) processes in modern tuning. Although it may seem like a dream come true to be able to throw an extra chip into your engine computer to magically produce more power, this is almost never the case. In fact, many of these mods will actually reduce the drivability of your car and mix if not harm your ECU. Thoroughly check out the company producing any chip.
There are many questions regarding performance chip tuning and whether or not it is potentially harmful for your engine. The answer to this question is varies, and it depends very much on the tuner and the car the chip is being installed on.
Engine Chip tuning can have widely varying results depending on the tuner and how they go about the tuning itself. Where safety tends to come into question, is in the case of universal chips or pre-programmed chips designed for a specific range of models. Because a tuner cannot properly anticipate the weather, fuel quality or pre-existing modifications to an engine, they can only give a generic tune based on compromises made by the manufacturer. Because safe tunes tend to generate less power than a riskier tune, many tuners will err on the side of performance due to the better selling points of bigger numbers, sacrificing reliability in the process. It is often because of situations like these and their resulting engine damage that the manufacturer’s Warranty is generally voided by installing a performance chip.
To properly tune an engine, each should be tuned individually whenever possible to address the owner’s specific driving style and engine modifications, as well as specific regional climate and weather. Excessively hot weather can be far more unforgiving to advanced timing and leaner fuel maps than cold weather, and an engine running higher compression or aftermarket cams will need a radically different tune than a stock engine. By tuning each engine individually, you can account for these differences, and tune in an acceptable compromise between performance and safety; something you will rarely find in generic chips.
Performance chips when improperly tuned can indeed be a dangerous addition to your engine, but this doesn’t mean all are. Look for experienced tuners and good reputations over flashy power gains and numbers and your experience with performance engine chips is far more likely to be an enjoyable one.