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.
Technosquare also tuned the multiple fuel maps, making them richer in some places and leaner in others (to run as close as possible to a 13:1 air/fuel ratio at full throttle). The VTC (variable cam timing) scheduling was optimized on both the intake and exhaust cams, not for NOX-reducing internal EGR, but for best power and torque. Also, the rev limit was raised to 8000rpm. Other changes include more part-throttle, light-load ignition advance for improved fuel economy and a more aggressive e-throttle response curve.
We used one of Technoquare's off-the-shelf reflashes to best represent a typical customer. For those with more aggressively tuned engines and/or forced induction, Technosquare can tune to accommodate boost, big camshafts, high compression, larger injectors and mass airflow meters with existing programs available for nearly all popular forced induction kits and naturally aspirated combinations on the market. Custom tuning by Technosquare's Tadashi Nagata is also available for local customers.
As our dyno test results illustrate, the Technosquare ECU made for gains across the board, fattening the powerband and smoothing out the power curve. The ECU flash resulted in a peak gain of over 9 wheel-hp at 7050rpm. Gains at the peak torque point were 16lb-ft at 4050rpm. Maximum gains were 26 wheel-hp at 6450rpm and a massive 54lb-ft of torque at 2000rpm. The seat-of-the-pants gains were also impressive with improved throttle response, smoothness and slight gains in fuel economy, mostly a couple more miles per gallon in highway driving. Other than having to buy more expensive premium fuel, we've yet to find any drawbacks to this reflash. Keep in mind that if your power modifications change significantly, a new reflash will be necessary to re-tune the ECU.
It's rare to find a modification that gives significant improvements throughout the powerband like the Technosquare reflash. It's also one of the quickest and easiest ways to get a substantial increase in power under the curve.