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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?

Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.