Most owners of bone-stock, or near-stock, LS1 vehicles have heard of handheld tuners. These wondrous little devices are best known for the ability to flash in a performance tune into the ECM-removing the conservative (and usually pig-rich) factory tuning and replacing it with more aggressive tuning more suitable for high-performance lovers.
These suckers have been around for years. From humble and basic beginnings consisting of the tune and not much more, the handhelds have evolved rapidly-enough in recent years to considerably close the gap between the handheld device and the more complex, laptop-based tuning suites. Not only are the included tunes much more accurate and very refined, but some offerings feature multiple complete tunes to choose from based on vehicle modifications, live engine data, custom tuning features, and even enhanced displays, dyno, and drag racing functions.
Though GMHTP has used many of the tuners you see on these pages for various projects before, we have never put a whole mess of 'em together, come up with the criteria deemed important to a potential buyer, and then tested and reviewed each tuner based on those criteria. We felt now was a good time to do such a test for several reasons: one, because it could pit an "old standard" group of tuners against a few newbies; two, because there are strong opinions and stereotypes regarding tuners that we hoped we could prove or refute; three, because I needed an excuse to make ridiculous amounts of dyno pulls and track passes in the name of research; and, most importantly, to give potential handheld buyers the information they need to make the right choice.
So I contacted 10 companies, explained what we were doing, and asked if they wanted in. Though two couldn't participate because their products weren't ready for testing, eight replied yes.
The test vehicle was 1SC-YA, my 2001 Z28 6-speed. This car's PCM had a stock 2001 F-body tune. The only drivetrain modifications were an aftermarket exhaust system, built 6-speed (stock ratios), and new clutch. This LS1 was fitted with a FAST dual wideband O2 system, and utilized scan tool/data logging software to keep track of the air/fuel ratio and spark timing of each tuner. Dyno, track, and subjective driveability testing was performed, all with Sunoco 93-octane premium unleaded fuel in the tank.
Dyno testing took place at TT Performance in Passaic Park, NJ (973/365-2270), utilizing their Dynojet. Coolant and oil temps were kept as consistent as possible for the most accurate results, utilizing a tuning suite and a digital laser thermometer on the oil pan. Two runs were made for each tune appropriate to my car's modification level. Some tuners only had one built-in tune, some had several.