1991 Corvette Zr1 7,409 Original Miles on 2040-cars

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'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).

Junkyard Gem: 1987 Chevrolet Turbo Sprint

Fifteen years ago, I wrote my first-ever automotive article under the name Murilee Martin, and it didn't take me long to start writing about one of my favorite automotive subjects: the junkyard. Before I'd refined my system for documenting discarded vehicles, however, I shot a lot of boneyard photos that never got used. For today's Junkyard Gem, I have four shots from early 2007 of one of the rarest turbocharged machines of the 1980s: the Chevrolet Turbo Sprint. The Chevrolet Sprint was really a rebadged Suzuki Cultus, from the pre-Geo era when General Motors sold the Isuzu Gemini as the Chevrolet Spectrum, the Daewoo LeMans as the Pontiac LeMans and the Toyota Corolla as the Chevrolet Nova (soon enough, the Spectrum became a Geo, and the Nova became the Prizm). The second-generation Cultus appeared in 1988, becoming the Geo Metro on our shores the following year. The Turbo Sprint was available for just the last two years of the Sprint's 1985-1988 American sales run, and it appears that just a couple of thousand were sold; if I'd known at the time just how rare they were, I'd have shot more photos of this one at the now-defunct Hayward Pick Your Part. The turbocharged 993cc three-cylinder produced 70 horsepower, 22 better than the naturally-aspirated version. Since the Turbo Sprint weighed just 1,620 pounds (that's about 500 pounds lighter than a barely more powerful '22 Mitsusbishi Mirage), it was plenty of fun to drive. For 1988, the regular Sprint hatchback cost $6,380 while the Turbo Sprint listed at $8,240 (that's about $15,375 and $19,855 today, respectively). Believe it or not, a Turbo Sprint actually raced in the 24 Hours of Lemons 10 years ago, though it didn't end well. This ad is for the regular Cultus, not the Cultus Turbo, but the screaming guitars sound reasonably turbocharged. For the most part, Chevy Sprint marketing was all about cheap purchase price and stingy fuel economy… at a time when gasoline prices were cratering. Related Video:

Next-gen Chevy Silverado and GMC Sierra may use carbon fiber

It's been generally accepted that the next generation of full-size GM trucks will use some sort of strong, lightweight material for the beds while retaining steel for the cab. While aluminum seems like the most obvious choice, according to Automotive News, the Chevy Silverado and GMC Sierra will incorporate both aluminum and carbon fiber in their beds. The publication cites sources from within GM, though it seems the introduction of this comparatively exotic material mix is still a few years off. While carbon fiber is both stronger and lighter than steel and aluminum, it takes significantly more time and money to produce, essentially relegating the material to small-volume cars. The main benefit for trucks is the resulting reduction in weight to improve fuel economy without sacrificing the tough, rugged capabilities truck buyers expect. The Ford F-150 made the switch to aluminum for the 2015 model year and it's proved highly successful. It seemed like it was only a matter of time before the competition followed suit. Automotive News says that the next-gen trucks will launch with aluminum beds and that it will take a couple of years before we'll see any carbon fiber incorporated into the design. Even then, only look for the composite material on higher-trim models, with a trickle down to lower-spec trucks possible further in the future. In 2011, GM announced it was working with Japan-based Teijin Limited on a carbon fiber reinforced thermoplastic. There's a good chance that material's introduction will be on trucks. Related Video: News Source: Automotive News Plants/Manufacturing Rumormill Chevrolet GM GMC Truck