Automobile Mag. Dyno Test of Sky Red Line

[Axel]

Automobile Mag dyno tested the turbo in a Red Line


(excerpts)

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.

Video of Dyno Test: (Windows does not seem to be working... the QuickTime does):
http://www.automobilemag.com/multime...red_line_dyno/

[Project_Redline]

That is pretty sick...suprised though...I thought the 260/260 would be underrated as well...shame...

[Shabodah]

Originally Posted by Project_Redline

That is pretty sick...suprised though...I thought the 260/260 would be underrated as well...shame...

I'm sure the engine is more underated than this shows. More drivetrain power loss here than on the Ion. Everything I'm seeing is pointing to the turbo sizing holding things back, too.

[jpapa]

Does anybody else see this thing not being easily tuneable right from the factory? The turbo is pretty much maxed out and a special system (twin scroll) that isn't that upgradeable. So if you were to replace it with a bigger non twin scrolled turbo, it might take A LOT of work to get the whole system working together smoothly. I say this because everything in that engine is designed and tuned as is to work at it's close to max state. For example, as the article mentions, the cam design to overlap the intake/exhaust valves to spool the SMALLER turbo (that wouldn't do as good of a job with a bigger/different turbo). The direct injection into the cylinders are most likely tuned to feed the engine in its max performance state (just like our injectors were maxed out from the factory).

I dunno, I could be wrong, but it just seems like all the different type of engineering that went into this engine/turbo application that you don't normally see in such systems, that it's going to not like to be modified. Pretty much just like our cars, but even worse.

I'm sure it's still upgradeable, but it will take a lot of money, time, and work to get a higher performance mode out of this engine. I don't really see a factory stage kit helping this powertrain either. The torque drops for the entire rev range, and the power peaks before redline. The turbo is already close to, if not maxed out, so more fuel wouldn't really create any more power.

I'm not trying to badmouth the car or engineering behind it, the turbo Ecotec still a blast to drive in any of the cars (thank you working for GM this summer :-D). I'm just seeing people having a lot harder of a time upgrading this car as compared to the more simple supercharged Ecotec...What do you all think?

[sheek360]

simply in awe of that engine.... that tq curve is insane, its like an ion RL's, but better!

[vandy0419]

I'm disappointed in the rwhp #s...

[vandy0419]

If anything is underrated from the factory its that damn 335i Twin Turbo Coupe! 300/300 claimed...dyno shows 275rwhp and 299lb/ft!!!

[NoRemorse]

Originally Posted by vandy0419

I'm disappointed in the rwhp #s...

I am not at all, this engine OCULD NOT have been underated like ours. Any GM engine going into production from 2005+ get indipendently dyno'd. It is an effort to get ALL automakers to do this, so automakers don't make BS claims about HP.

[vandy0419]

Originally Posted by NoRemorse

I am not at all, this engine OCULD NOT have been underated like ours. Any GM engine going into production from 2005+ get indipendently dyno'd. It is an effort to get ALL automakers to do this, so automakers don't make BS claims about HP.

Ah, for insurance reasons and stuff? How did out 06s and 07s stay underrated then? Or is it just when a new model is released they do it? Doesn't make sense with that BMW then.

[NoRemorse]

Originally Posted by vandy0419

Ah, for insurance reasons and stuff? How did out 06s and 07s stay underrated then? Or is it just when a new model is released they do it? Doesn't make sense with that BMW then.

GM is doing it with only ENGINE put into production after 2005.

Like she SRL's LNF.

It is comepltly voluntary though, automakers can choose to do it or not.