2005 Chevrolet Cobalt Ls Coupe 2-door 2.2l on 2040-cars

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2016 Chevrolet Colorado Diesel First Drive [w/video]

The first thing you notice inside the diesel Chevy Colorado is that it's quiet. Almost too quiet. A lot has been done to quell noise and vibration with this new powertrain, and it shows – or rather, doesn't. There's some characteristic diesel clatter at idle, but even then it's distant and practically disappears as you start moving down the road. At full throttle, when the engine is at its noisiest, the sound isn't particularly diesel-like, just a pleasant intake breath. The accompanying smoothness is almost eerie. When we ask where all the noise went, Chevy's engineers, marketing guys, and PR reps all explain that this refinement is what Americans want. We're still not sure. This is a truck, after all, and the diesel pickup customer is different from the guy buying a diesel Cruze for his highway commute. Chevy contends that they're also not the same as the buyer of a Silverado HD. Although this 2.8-liter Duramax four-cylinder has been in service elsewhere around the globe, its first US application is in the Colorado and its GMC Canyon twin. The engine puts out 181 horsepower and 369 pound-feet of torque, and it does so unobtrusively as a result of a lot of modifications for our market. To keep normal diesel sensations out of the cabin, the intake and oil pan both get acoustic treatments. A new, thicker material is used for firewall sound deadening. Redesigned balance shafts have tighter tolerances to increase smoothness. The diesel powertrain is smoother than the Colorado's gasoline V6. One of the more interesting and certainly unexpected vibration-reduction changes is a special torque converter from German supplier LuK equipped with a centrifugal pendulum absorber. This pendulum spreads from the center of the torque converter as engine speed increases and is tuned to absorb the four-cylinder's second-order vibrations, not just those in a narrow frequency band. It does an admirable job, especially considering the engine's biggish, 0.7-liter cylinders, which lead to bigger vibrations. The result is a powertrain that's smoother than GM's (not particularly smooth) corporate V6, which is available in the standard Colorado. It's quieter than a Cruze diesel and even out-softens some gas direct-injection engines on the market. Paradoxically, it may be the most refined of all of the Colorados. No vibration comes through the steering wheel, pedals, floorboards, or even the rearview mirror. But you can tell it's a diesel when you hit the throttle.

Before Chevrolet's Redline, there was the Saturn Red Line

While Chevy rolls out Redline special editions across more of the lineup at this year's Chicago Auto Show, we've been eating some 'member berries and started thinking about the last time GM used the term. Back in 2004, Saturn rolled out Red Line (two words) editions of the Ion and Vue. The lineup was joined by the Sky Red Line in 2007, and the second-generation Vue kept the tradition going in 2008. This was in the heady days of the mid-2000s, before the financial crisis and GM's bankruptcy reorganization that saw the end of Saturn. The press release headline for the 2008 Sky is now cringe-worthy: "Hot-selling Sky helps drive Saturn product renaissance." Performance lineups were the hot new thing, as automakers attempted to cash in on the tuner trend popularized by The Fast and the Furious. Chevy had SS models, Pontiac had GXP, and Saturn had Red Line. Across the Detroit Metro area, Dodge had a slew of SRT models, and Ford's Special Vehicle Team brought us the SVT Lightning pickup, the SVT Focus, and a smattering of hopped-up Mustangs. The performance cred of Red Line models varied from car to car. The Ion Red Line shared the same engine as the original Chevy Cobalt SS, a 205-horsepower supercharged 2.0-liter four-cylinder, 65 hp more than stock. Car and Driver tested one with a 0-to-60-mph time of 6.1 seconds and said the Ion "tears down the wall that has separated enthusiasts from the Saturn brand for so long." The Vue Red Line, meanwhile, came with the same optional Honda-sourced 3.5-liter V6 you could get in the regular Vue, and added a stiffer, lower suspension, bigger wheels with more aggressive rubber, and recalibrated steering assist. When the Vue was redesigned for the 2008 model year, the Vue Red Line was a similar proposition. The engine was now from GM, and up 7 horsepower to 257, but you could get it in both Red Line and XE trim. Aside from the tire and suspension upgrades, Red Line models now came with a unique front fascia and rear exhaust cutouts. The most exciting Red Line, of course, was the high-performance version of the Sky roadster, which shared underpinnings with its Pontiac Solstice twin. This model came with GM's hot 2.0-liter Ecotec Turbo, good for 260 horsepower. The extra power was crucial in covering up the Sky's unfortunate manual gearbox ratios, which left the non-turbo model aching for torque in lower gears. As we all know, Saturn was taken by the grim reaper in 2009 after an attempt to sell the brand to the Penske Group.

'Killing a Duramax' Gale Banks YouTube series methodically tunes a diesel to death

Learning or perfecting a skill by watching YouTube videos is known as attending YouTube University. GM Authority picked up on one of the video site's more fascinating courses, hosted by Gale Banks; in a fair world, he should be referred to as Professor Banks when it comes to diesel engines and truck tuning. A few months after GM introduced the updated L5P 6.6-liter Duramax diesel V8 in the 2020 Chevrolet Silverado HD and GMC Sierra HD that ships with 454 horsepower and 910 pound-feet of torque, Banks decided he wanted to methodically tune the engine to death. The purpose of the resulting series, called "Killing a Duramax," is to push more power out of the engine in order to discover which parts break and when — or, as Banks puts it, force-feed the Duramax "until the crank hits the street and the heads hit the hood." With that knowledge, Banks can figure out all the weak points on his way to building what he calls a "Superturbo," that being a supercharged, twin-turbo race engine with more than 1,000 hp. What makes the series fascinating is Banks' knowledge, paired with the company's comprehensive iDash engine monitoring system that keeps tabs on a glut of parameters every step of the way. So for instance, you get Banks explaining the differences between inches of mercury and barometric pressure, how those are different from the water content of the air measured in grains, then showing those readouts on the iDash, then explaining in detail how they affect the air density in the Duramax system. The stock Borg-Warner variable turbo gets a lot of airtime — Banks accuses it of being "out to lunch" because he feels it's the weakest link on the engine. That turns into a turbo teardown and a deep explanation of performance pitfalls, such as when air pressure on the turbine begins to diverge from the boost pressure coming from the compressor. Banks says he can keep close tabs on where power's coming from, because the iDash monitors the horsepower contribution provided by the ambient air, the turbo, and the intercooler separately. The major changes so far are a stouter Precision 7675 turbo and TurboSmart wastegate (episode 5), a twin intake (episode 6), a custom liquid-cooled intercooler from a marine engine, a new GM oil cooler and synthetic oil (episode 10), and new injectors (episode 11).