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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).

2021 GMC Sierra 1500 Review | More towing, same truck

The 2021 GMC Sierra 1500 and the Chevrolet Silverado 1500 are close siblings, and they’re getting closer every year. One of the SierraÂ’s previous standout features, the Multi-Pro tailgate, can now be found on the Silverado for 2021, providing even fewer reasons to choose the GMC instead of the Chevy. Really, if youÂ’re looking at the more modest SLE and SLT models, the choice between the two largely depends on styling preference. The Sierra Denali is a slightly different story, as its available adaptive suspension is exclusive to GMC and notably improves both the ride and handling.  Of course, it still can't match the Ram 1500 in either regard, plus the Denali cabin continues to be a rather half-hearted attempt at luxury. Especially considering the genuinely high-lux offerings of Ram and Ford. The gap isn't so huge between the Sierra's lower trim levels and its non-Chevy competitors, but the cabin's design, quality and functionality still leave something to be desired. True, that often isn't a priority for truck buyers, but the Sierra isn't superior in enough other ways to balance it out. It's a capable truck with a compelling variety of powertrains, but it generally just doesn't go that extra mile beyond the competition as well as its Silverado sibling. What's new for 2021? Changes for 2021 are mostly equipment-related, but there were some vital towing and pricing changes made for the new year, too. All 2021 Sierra 1500s come with a suite of new towing tech detailed here. New technologies include a trailer length indicator, jack-knife alert, trailer backup guidelines, and camera enhancements that include a rear side view and cargo bed view. GMC expanded availability of the Multi-Pro tailgate, now allowing folks who opt for the lower SLE and Elevation trims to option it. The AT4 adds new Goodyear Wrangler Territory all-terrain tires and an off-road high-clearance step. Diesel buyers will be delighted to hear that GMC has lowered the price by $1,500 to $995, and raised the trailering capacity by 1,900 pounds to a more competitive 9,300. Maximum towing for the 2.7-liter turbo-four-cylinder is also up by 2,300 pounds to 9,200 pounds. GMC says the increase for the diesel is due to “better-than-expected rear axle durability,” and the four-cylinder is up because GM found the engine possesses “better-than-expected cooling performance.” What's the interior and in-car technology like?

2021 GMC Sierra adds towing tech, new HD Black Diamond Edition

Trailer towing is the focus of several new technologies coming to the 2021 GMC Sierra pickup, with the new features available both on the Sierra 1500 and the Sierra HD. The 2021 Sierra also sees expanded availability of GMC's MultiPro tailgate, a price cut for the available 3.0-liter Duramax turbodiesel six, and a new Black Diamond Edition of the Sierra HD. Pickup truck makers are engaged in a trailering-technology arms race. Already, the GMC Sierra offers its ProGrade Trailering package that features a "Transparent Trailer" virtual camera view and a Rear Trailer View that uses an auxiliary camera mounted on the back of the trailer. To that, GMC is adding a Trailer Length Indicator that can alert drivers of another vehicle in the adjoining lane during a signaled lane-change. A new Jack-Knife Alert warns the driver if the front of the trailer approaches the rear of the tow vehicle. The warning appears in the center screen and can also trigger a seat vibration. The previous Rear Side View split-screen now also works when reversing and adjusts for the angle of the trailer. The Cargo Bed View now includes a zoom feature and hitch guidance for connecting gooseneck trailers. Finally, the previous Rear Trailer View adds a trailer-angle indicator and dynamic guidelines. In other equipment news, the six-position MultiPro tailgate is newly available on the Sierra 1500 SEL and Elevation trims and standard on the Sierra HD SLE. The fancy Sierra HD Denali adds Surround Vision and Bed View cameras to the standard-equipment list. Standard and optional engine choices for the Sierra are unchanged for 2021, but the price of the optional 3.0-liter turbodiesel engine in the Sierra 1500 is reduced by $1,500. For 2021, on models where the 5.3-liter V8 is standard (SLT, AT4, and Denali), the upcharge will be $995. For the SLE and Elevation, where the 2.7-liter V6 is standard, the cost to upgrade to the diesel is now $2,390, again a decrease of $1,500. Lastly, the Sierra HD adds a Denali Black Diamond Edition. It includes 20-inch gloss-black wheels, power-retractable side steps, premium audio by Kicker, an Auxiliary Trailer Camera, trailer tire-pressure monitor sensors, and premium floor mats with removable carpet inserts. It comes in any color you want so long as it's Ebony Twilight Metallic. The Black Diamond Edition is pictured above. Related Video: