Flash tuners are all the rage now. After the evaporation of ECM "chips" from the OEs' offerings around 1993, it took a solid 10 years or so for the PCM re-flashing business to evolve into the reliable and fairly optioned market it is today. Carputing partners, Ken Kelly and Dave Hempstead, have been two of the pioneering forces that have consistently led the pack along the way. We found it most appropriate for the next step in our continuing GMHTP flash tuner series to test Carputing's latest offering, LS2-edit. Carputing got its start back in 1999, when principals Ken and Dave met each other through a chance virtual dialog jawing about LT1 transplants on an Internet message board. Ken, a 28-year veteran of cellular research at Bell Labs, was dropping an LT1 powertrain into a 1948 Ford roadster and Dave was installing an LT1 in his 1934 Ford roadster. The duo, armed with a combined 56 years of professional electronics and computer experience, quickly realized they could "build a better mousetrap." The mystique of flash-memory type PCMs was still cloudy at the time. Enter LT1-edit. It didn't take long for the word to spread about LT1-edit and with that came the demands for a similar LS1-based tuner package. Carputing responded with the first flash tuner available to the masses for reprogramming the LS1 PCM. Since then, Ken and Dave have consistently been the first to market with subsequent packages covering all Gen III/Gen IV powertrain offerings, from 1997 through 2006.
LS2-edit, or 'Edit for short, is based on the same familiar LS1-edit architecture. Emphasis is on function and capabilities, rather than fancy colors and loads of graphics. Several notable improvements have arrived with LS2-edit. The flasher-to-computer interface is now super-fast USB-based, rather than the old and slower serial connection. The flashing process has evolved into a seriously robust and safe process, practically eliminating the infuriating side effect of any mishaps during the flash process that, historically, could result in frying your PCM into a doorstop; Ken tells us no ECMs have been "fried" with LS2-edit. Yes, ECM, not PCM. The LS2 arrived with a split powertrain controller running on a new CAN interface; an engine control module (ECM) and a separate transmission control module (TCM) communicating across the General's new controller area network (CAN). The good news is that LS2-edit covers both. The ECM and TCM parameters are both 'Edit-able. The entrance of the CAN interface was a huge obstacle to overcome when introducing LS2-edit. Rather than simply deciphering the '05 codes for the LS2, Carputing had to develop a new module and computer interface capable of working with GM's tricky new CAN setup.
'Edit continues to be a work in process. Included with each purchase of 'Edit is a 6-month update service agreement. Every time an update or revision to 'Edit becomes available Carputing emails a set of new files to active recipients. Beyond the included six-month agreement, subscriptions are offered for $50 per year. The update system allows consumers to get their hands on 'Edit as soon as possible--and get the basics of the tuning handled up front. As the program evolves, additional work can be made to the tunes. The system also allows feedback to help drive development. Asusers push for features, Ken works to add them to the next revision.
Getting started with 'Edit is straightforward. A visit to www.Carputing.com and a credit card with $550 will get you started. A few days after ordering 'Edit, we received a complete package including the flash module, all necessary cables, a CD with the program, and a few instruction sheets. Within a half-hour, we were hooked up to the ALDL connector on our test 2005 C6 and downloading the base tune. For those who are lighting up their first 'Edit experience, helping advisors are available. Carputing offers an optional group email exchange forum subscription to buyers. Any questions can be emailed to the "forum subscribers," basically consisting of all prior 'Edit buyers/users. Typically, within minutes of blasting out an email, someone will respond. This is an excellent and powerful experience-sharing mechanism. If that fails to satisfy, most of the major message forums have dedicated 'tuning' sections for communication. Fellow tuners are quick to offer assistance, advice, and often sample tunes. We recommend jumping in (to the tuning pool); the water is fine ... as they say.
LS2-edit is available in two versions--licensed for a single PCM ($550) or licensed for unlimited PCMs ($2,995). If you order the single license version, you can also add a license for additional vehicles for $100 per extra vehicle. For our evaluation of LS2-edit, we secured a willing 2005 Corvette C6, equipped with a bolt-on beefed LS2 and an automatic transmission. Our baseline dyno testing yielded an SAE corrected 383.5 rwhp/378.9 rwft-lbs. Wide-band readings recorded a rich 11.5:1 air/fuel ratio at WOT. Spark advance was logged at a lazy 20 degrees BTDC at WOT. From prior experience, we know the Gen III/Gen IV makes peak power in the vicinity of 27 degrees BTDC and 12.9:1, so our fuel and spark tables needed work. Besides dialing-in the fuel and spark delivery, our transmission tables needed some hot-rodding. The C6's factory shifting schedule is well on the conservative side, leaving plenty of room for improvement. Stock torque converter lockup comes on really early, and downshifting is only programmed for nearly WOT command. Stock upshift points are not bad, but we wanted to squeeze a few more rpm out of each gear to complement a reassigned rev limit. After some experimenting on the dyno, we found the sweet spot to be 27.5 degrees of spark advance at WOT, to ignite fire on our leaner 12.9:1 WOT command. We turned off the catalyst over-temperature enrichment during testing to allow us to dial-in the base fuel ratio. After testing, however, we re-enabled COT service. From our track testing data logs we've found the COT not to be a problem when the vehicle is moving at high speeds off a dyno. We ended up with SAE corrected 393.5 rwhp/386.0 rwft-lbs. In addition to the gains on the dyno, we also fixed a few other issues. We zapped the infamous MIL set from our long tube headers. We bumped the rev limiter up 200 rpm and added 50 rpm to each shift point. We also (bravely) deleted what was listed for torque management.
The Transmission Calibration section is arranged in four main subsections including "Gear Tire," "A4 TCC," "A4 Shift Firmness," and "A4 Shift Speed." The gear ratio setting is the TCM's record of final drive ratio, in our case a highway lover's 2.73. | 
Torque converter lockup control is highly adjustable. Both on-lock and off-lock can be tuned. The bulk of the work in here will be around an aftermarket converter, yet one could adjust even a stock converter's behavior as desired. | 
Infamous torque management (overstress torque reduction) is exposed in a few different areas between the TCM and ECM. In the trans tables we found the upshift torque reduction tables used to limit or reduce engine torque between shifts. |
Shifting firmness is tunable based on throttle position at a certain temperature in a selected gear. This table will require somewhat of an iterative approach to get right. Making changes of five units at a time in a bulk section of the table works well to get it close. Fine tuning can be done from there. | 
Shift speeds at wide-open throttle (WOT) are set based on mph and rpm to initiate the shift. Different tables are used based on the area of operation (Normal Mode, Performance Mode, Cruise Mode, Hot Mode, 1 WOT). The mph table should be set first, then rpm. The settings are for the start of shifting, which takes time to complete, so the higher speed shifts are initiated earlier to allow completion prior to hitting the rev limiter. | 
Part throttle shifting is tuned by mph at a TPS percentage in a selected gear. For starters, the downshifts speeds can be cranked up, so you can actually use First gear over 10 mph. |
The ECM file is organized into four main categories including: Engine Diagnostic, Speedometer, System Calibration, and Engine Cal. After loading the ECM file, each of the main categories can be toggled. | 
The Engine Diagnostic section is split between Hardware Diagnostics and Test Parameters. Under the diagnostics tab we are able to alter setting sequence or disable each DTC code. Codes are labeled using the GM diagnostic code number, so you'll need to refer to a service manual to find details and definitions for the corresponding DTC codes. | 
Test parameters for the main DTC troublers are listed under the Test Parameter tab. If you're running long-tube headers, cat-eliminators, a modified MAF, forced induction, a big cam, or more cubes, you'll need to work in this area. |
The misfire diagnostics table can (and should) be tuned for engines when needed. If the misfire code is setting, you need to work with this table. It is a better idea to adjust this table rather than simply shut it off. Normally, the idle rpms are dialed out and the mid and high rpm range is left active. If your exhaust is loud and your idle is rough, this table can help warn of an early problem. | 
Speedometer scaling is needed when a gear swap or tire diameter change is made. The speed limiter can also be disabled on this tab. | 
The System Calibration tab in the ECM file primarily covers fan control. The variable speed electric engine fan can be adjusted around a changed thermostat. You can also shut the VATs off in this tab. |
The Engine Cal section is the largest and most powerful section of the ECM code. The engine calibration is organized in six self-explanatory sections including, "Idle-Limits," "Fuel," "Skip Shift," "Ignition," "Torque," and "Parameters." On the "Idle-Limits" tab, tables controlling the idle airflow are found. Large cammed engines and increased displacement engines will require work in these tables. | 
The engine rev limiter is easily adjusted for cutoff in each gear. A buffer of a couple hundred rpm is needed to allow shifts to complete before hitting the limiter. | 
The "Fuel" tab houses all fuel delivery related parameters. A few scalars on the tab can be tuned for displacement, cat overtemp protection (COT), and power enrichment settings (PE). |