According to several sources with unconfirmed track records with GM Authority, GM Performance Parts (GMPP) is working on “stage kits” for the Chevy Cruze and Sonic. Details are sparse, but the sources have specifically pointed to the 1.4 liter turbocharged four-cylinder Family 0 engine that carries GM’s LUJ RPO code as the engine for which the kits are being engineered.
Histrorically, the kits have been available in stages (such as Stage 1, 2, 3), with each higher number denoting a superior level of performance. The kits usually offer an ECM tune, enhanced fuel injectors, intake and exhaust systems, as well as performance upgrades for the vehicle’s forced induction system and suspension. Since the Stage Kits are engineered by Chevrolet/GM Performance Parts (GMPP) and installed by a dealer, their use does not affect the vehicle’s warranty while the parts contained in the kit often carry warranties of their own.
For reference the Stage 1 kit for the now-discontinued Chevy Cobalt SS consisted of enhanced fuel injectors and a reprogrammed ECM that delivered an increase of 30 hp. Stage 2 consisted of the items in Stage 1 but delivered a smaller serpentine belt and pulley for the Cobalt’s supercharger, delivering a 47 hp and 30 lb.-ft. of torque improvement over the stock Cobalt SS. Finally, the Stage 3 kit took things to the extreme, as its use was restricted to tracks and disabled the Cobalt’s air conditioning; it included a smaller supercharger pulley, a 2-pass intercooler end plate, and a customizable replacement ECM; the Stage 3 ECM makes room for the use of a 50-shot of nitrous, 100 octane fuel, and an adjustable redline (from 6,750 to 8,000 RPM), delivering 248 hp (on 93 octane) and up to 260 hp when running on 100 octane fuel.
The GM Authority Take
The development of Stage Kits for the Sonic and the Cruze wouldn’t surprise us in the least. But what we’d rather have is either one of those vehicles in a more powerful form directly from GM. Hyundai seems to get it just fine; why doesn’t Chevy?