The Gen III LS1 engine factory-installed in '98-'02 Firebirds, '04 GTOs and the Gen IV LS2 between the fenders of the '05-'06 GTOs are excellent powerplants. Current LS2 engines are rated at 400 hp with 400 lb-ft of torque and are capable of low 13-second e.t.'s in stock form. The LS1s are not too far behind.
Significant power increases can be realized with a careful selection of aftermarket parts including headers, camshafts and power adders. But common among all modifications is the necessity of having your computer tuned to ensure that your Pontiac runs safely and to maximum power. Even for owners who have no intention of modifying their Goats or Birds with aftermarket speed parts, additional horsepower and torque can still be gained by having your LS1 or LS2 custom tuned.
Seemingly, a whole industry has been created for tuning the modern computer-controlled car. Hand-held programming companies were formed to break the code of the domestic OEM programming software in order to create generic performance tunes, thus allowing the enthusiast to "flash" a revised program into his vehicle.
After the rollers stopped...
After the rollers stopped spinning for the stock '06 automatic GTO on Real Performance Motorsports DynoJet 248 chassis dyno, 302.7 rwhp and 307 lb-ft of torque was the baseline. The air/fuel ratio was rather rich at 12:1, while the total timing maxed out at 17 degrees at WOT.
Although some companies offer user-selectable options within the programming to change certain tune parameters, such as transmission shift firmness or a plus/minus percent on fuel or timing, the hobbyist looking for a "custom tune" has turned to the modern-day methods. Specialists are now equipped to provide individual tuning to maximize the engine's performance and match the specific combo.
According to Brian Lohse, co-owner of Real Performance Motorsports, "whether the Firebird or GTO is stock or highly modified, we can create a tune using HP Tuners software. On a completely stock LS1- or LS2-equipped car, our custom tuning averages gains of 10-15 rwhp. Gains of as high as 30 rwhp have been achieved on the high-end with no loss of reliability or any of the attributes that make the LS series of engines idle, drive, and run so strongly.
"From the factory, the GM programming for the LS1 and LS2 is a bit conservative, especially if equipped with an automatic transmission. In order to meet all varieties of governmental regulations, the baseline tunes do not provide maximum performance. Timing is set to max out under wide-open throttle (WOT) at 17-19 degrees while the air/fuel (A/F) ratio is a bit rich at 12:1.
The HP Tuners Standard hardware...
The HP Tuners Standard hardware interface and software allows all of the tuning and data-logging capability that is built into the VCM Suite for $499 (shown). The professional version retails for $649 and can log data from outside sources, such as a wide band O2 sensor, while allowing interface to the vehicle without a laptop.
"Automatic equipped GTOs are further handicapped by aggressive factory Torque Management (TM), designed to reduce the available torque by as much as 40% on the 1-2 shifts, supposedly elongating the life of the transmission.
"Our tuning experience runs the gamut of stock LS series cars, all the way to wild combinations that have everything from long duration camshafts to blowers, turbos and nitrous. On a stock '05-'06 GTO, timing is advanced to 22-26 degrees while the target A/F ratio is adjusted to achieve between 12.5:1 and 12.9:1. With hundreds of tunes available in our library, creating a custom tune for the hobbyists' combination is easily achievable."
HP Tuners VCM Suite
Real Performance Motorsports (RPM) uses HP Tuners VCM Suite, which includes HP Tuners VCM Editor and VCM Scanner, to perform tunes on all GM-based Gen III and IV vehicles. Inside the HP Tuners VCM software is a comprehensive selection of choices, logically arranged by vehicle functionality, which enable a professional tuner shop or highly skilled home hobbyist to tune and scan the GM-based computers. Much of the tuning using the HP Tuners software will be focused in the areas to follow. It should be noted that the LS2-based GTOs have both an ECM (Engine Control Module) and a TCM (Transmission Control Module).