Dynamometer Test: 2007 Saturn Sky Red Line
The Saturn Sky is gorgeous, but that's not exactly a secret. You're also probably aware that the Red Line version gets a limited-slip differential, a performance-tuned suspension, and dual exhausts.
But forget all that. The most interesting thing about the swiftest Sky is without question its engine. And this isn't some half-assed, hobbled-together, turbocharged old lump we're talking about. Need proof of the new-think? Saturn fills the thing with Mobil 1 synthetic motor oil at the factory.
This state-of-the-art, turbocharged and intercooled, sixteen-valve in-line four is GM's first direct-injection engine in the US, and it's been renforced to better handle the turbo's 20 psi. The powerplant also has the highest output--and the highest specific output--of any engine in the Ecotec family: 260 hp and 260 lb-ft of torque. That's a lot of power for a 2.0-liter engine.
By injecting fuel directly into the cylinders, GM was able to maintain a relatively high compression ratio (9.2:1), which helps the engine make more power off-boost and also contributes to better overall efficiency. Continuous cam phasing on both the intake and exhaust cams further increases efficiency and helps reduce turbo lag. For example, at low revs, the engine computer will allow a small amount of valve overlap, opening both the intake and exhaust valves at the same time. This increases the volume of gases flowing through the turbo, keeping it spooled up and ready to produce boost.
To wit: Mash the accelerator from idle and the twin-scroll turbo starts building boost almost immediately. All too often, having a turbo small enough to spool up quickly at lower revs means that it runs out of breath as the tach needle hits the fun end of the spectrum. But that's simply not the case with the Sky Red Line. The 6300-rpm fuel cutoff might be relatively low, but the little motor pulls hard all the way to the top, and all the techno goodies work together to make the displacement-challenged Red Line drive more like a normally-aspirated car with a big, honking motor.
We were impressed with the Red Line's ability to make power all over the rev range, but why should you take our word for it? We took it to a chassis dyno so you can see exactly what it puts out. And the Sky's rough and tough exhaust note made everyone turn around and listen. So, naturally, we grabbed the video cameras, and you can hear it for yourself.
On the dyno, the Saturn Sky Red Line put 228 hp and 248 lb-ft of torque to the rear wheels. Those are very, very impressive numbers. The peak torque number is quite a bit higher than we expected, but more impressive still is the shape of the torque curve. This little monster put down more than 200 lb-ft of torque from 2000 rpm to almost 6000 rpm.
The Ecotec isn't a particularly smooth or refined engine, but the dyno run backed up our impression that it provides truly world-class power delivery. The next time you see someone driving a Sky Red Line or its mechanical cousin, the Pontiac Solstice GXP, you'll know that their ear-to-ear grin isn't just due to their car's gorgeous looks.