Featuring GM's revolutionary turbocharged Ecotec 2.0L powerplant that produces respectable power and previously propelled our test Cobalt SS to Mustang GT level performance with merely a tune. (July 2009). However, in this incarnation the Sky's RWD, hardy five-speed gearbox, standard limited-slip differential, and independent rear suspension, makes the roadster more akin to a Vette than a subcompact.
Like many, I was a bit dismissive of the Sky, until one night at "Route 59," a notorious and unsanctioned automotive event held just north of New York City. It was there the Sky's sharp lines and aggressive, yet well-proportioned stance lured me in for a closer look, where I met Eros Deda and his '08 Sky Red Line. After the obligatory introductions, I asked the diminutive 22-year-old why he chose the Saturn over the slew of imports popular with his peers. "It's got balls and Hondas are like Tampax every [expletive deleted]'s got one," he replied to the chagrin of the many Civic aficionados present. "I was thinking about getting a Z, but this just pulled harder and felt better in the turns, plus I like that you don't see too many around here." When I inquired if he had plans to do some modding he hesitantly replied, "definitely, but it's pretty new, I don't want to do anything that would blow it up."
Thankfully the engineers at GM did their homework before adding boost to the Ecotec mill. Instead of simply adapting the 2.4L mill in the naturally aspirated base model, the Red Line features the LNF Ecotec 2.0t. Cranking out 260 hp and 260 lb-ft at the flywheel, the 122-cid four-banger extracts an amazing 2.1 horsepower per cubic inch of displacement-making it GM's highest specific output engine ever. The engineers were able to achieve this by combining advanced technologies such as a dual-scroll turbo, variable valve timing, and direct injection. Working in harmony, the dual cam phasing complements the turbo system by optimizing valve timing at lower rpm for faster turbo spool and quick torque, while utilizing the injectors' efficient delivery to enhance piston cooling. "There is virtually no lag with this system," said Ed Groff, Assistant Chief Engineer at GM. "Throttle response is immediate. The engine acts like a larger displacement engine."
More robust than its predecessors, the "Gen II" Ecotec block was developed in conjunction with GM's racing division to support increased horsepower and torque. For instance, the cylinder block's bulkheads and the bore walls are enlarged for strength along with a deeper water jacket design for added cooling capacity and improved cylinder bore roundness. With all this in mind, I was curious to find out how GM's newest engine responded to a few typical modifications.
I alleviated any lingering reservations Eros may have held by selecting very light mods made by some of most reputable suppliers in the industry. The hard parts would consist of a K&N Performance drop-in air filter and a Magnaflow cat-back. Also, we again recruited local GM guru Matt Hauffe of Tune Time Performance to perform the installs and recalibration of the Sky's ECU utilizing HP Tuners VCM software suite.
With my subject car secured, Eros and I headed down the Garden State Parkway one recent afternoon to see Matt and the boys at Tune Time Performance in Toms River, NJ. First, we performed a baseline run, which yielded 234 rwhp and 246 lb-ft-a bit lower than Cobalt SS. Hauffe speculates this loss may be a result of the Sky's rear-wheel-drive configuration and beefier transmission. Next, we replaced the stock air filter with the K&N, to say it was a extremely quick and easy install is an understatement. However, it increased output by 8 hp, but with no gains to torque. Then we put the car in the air and removed the restrictive, and far too polite, stock cat-back with a brand new MagnaFlow Quad-tipped 3-inch system. The upgraded cat-back produced gains of 8 hp and 11 lb-ft bringing our totals to 250 hp and 255 lb-ft of torque.
With the bolt-ons installed, it was now time for Matt to work his laptop magic. Matt, already being very familiar with the Ecotec 2.0t, was quickly able to produce a gain of over 20 rwhp and 46 lb-ft of torque over our previous runs after only four pulls. Matt was able to accomplish this by manipulating the load tables to increase peak boost to 23 psi and limit the taper to 20 psi by redline. At this point the turbo seemed nearly maxed out, and the timing was increased, though not overly-aggressive-unlike the factory, Hauffe believes no degree of knock is acceptable. With the final numbers of 270 rwhp and 300 lb-ft, this gave us a total gain of over 36 rwhp and 54 lb-ft over stock. Matt conjectured the gains made with a more aggressive tune would not be significant enough to justify any potential damage to the engine. Matt went on to speculate that with a lager turbo and water/methanol injection, this little engine could be pushed much further.
A week after our day at Tune Time I met up with owner Eros Deda to see what he thought of his new-found horsepower. He said, "before I really never beat on my car, but now I just can't help ripping it all the time." He continued, "I want more," and then asked, "Who did you say makes a turbo upgrade for my car again?"