In the mid-1990s, in an effort to improve customer service, satisfy government regulators and to reduce warranty costs, car manufacturers started to produce ECUs with the ability to be reprogrammed or reflashed through the OBD-II port. Today, all automotive ECUs can be reflashed by the dealer.
Although this would seem like a boon to the performance aftermarket, it hasn't turned out that way for enthusiast owners of many marques. Automotive manufacturers don't want the aftermarket messing around with their ECUs, in case an errant tuner gets a little too aggressive and blows a few motors. A quick flash of the ECU back to stock and a tow to the dealer can also result in a costly fake warranty claim.
To prevent this scenario, OEMs encrypt the data needed for reflashing. The technical stuff behind this encryption is quite involved, beyond the scope of this article, but let's just say that unless you're a computer engineer schooled in this stuff, your eyes will glaze over. If you're lucky and own a Mitsubishi, Subaru, VW, GM or something from a few other makes, then there are many tuners who have cracked these ECUs. You may even be able to download shareware from the internet to do some flashing of your own.
For owners of cars from some other brands, the choices are either non-existent or scant. In the case of Nissan, there are very few companies in North America that can reflash and/or do custom tuning of a factory ECU, especially for the newer VQ motors. But one of them is Technosquare. You may have read about this operation's mechanical and fabrication prowess in this magazine. It's also the North American vendor for TechTom. TechTom is one of the pioneers of factory ECU programming in Japan and has developed ways to reprogram many OEM Japanese ECUs.
To test Technosquares's tuning chops, we found a suitable 350Z test mule. This 2007 Z has an internally stock VQ35HR motor with a Nismo cat-back exhaust and an Injen cold air intake system-a good representative of a typical street Z. We ran the car on the Dynojet chassis dynamometer at MD Auto in Westminster, California, and did several consecutive pulls until the horsepower figures stabilized to get our baseline. Then we reflashed the ECU with a performance program, re-dyno'd, then reflashed the ECU back to stock and compared the power figures with our initial baseline. This would assure that our power gains were truly from the reflash, not the ECU's self-learning function adapting to and optimizing itself for the dyno's load characteristics. Fortunately for us and MD, reflashing only took a few minutes.
To squeeze more power from the ECU, Technosquare removed some of the compromises associated with OEM tuning for emissions and low-octane fuel operation. This means that many of the low areas in the timing map associated with areas of high NOx production, or a propensity to detonate on 87-octane, were filled in with numbers meant to generate the greatest amount of power.
As an interesting note, screwing around with the timing maps on a late-model Nissan is not as straightforward as editing the spark tables on an aftermarket ECU, like a AEM EMS or a Motec. Nissan's ignition control algorithm is built around the amount of cylinder pressure generated at any given moment and the editable tables are cylinder pressure constants, not degrees of advance. Although changing the numbers here mostly affects ignition timing, there isn't a 1:1 correspondence between the number entered and what timing the engine is going to run. This makes tuning somewhat tricky.
By Mike Kojima
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