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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).

GM can't keep up with most popular pickup orders

With the market for pickup trucks at its best since before the recession, General Motors can't afford any hiccups with the launch of its new 2014 Chevrolet Silverado and GMC Sierra twins, but it sounds like the popularity of V8-powered trucks is causing some supply-chain issues. Bloomberg reports that GM is experiencing a shortage of 5.3-liter V8 engines because an unnamed parts supplier has been unable to keep up with demand. This is leading GM to restrict the number of V8 Silverado and Sierra trucks that Chevrolet and GMC dealers are allowed to order.
Although it's unclear how long it will take to resolve the parts shortage, GM doesn't have much time to sort it out, as a new Ford F-150 looms on the horizon. At launch, GM's fullsize trucks were offered only with a base 4.3-liter V6 and the 5.3-liter V8, but a burlier 6.2-liter V8 will be available soon. Interestingly, at least at the moment, GM truck buyers don't seem as willing to downsize to V6 power as buyers of the F-150, which gets some 42-percent of its sales from trucks equipped with its EcoBoost V6 engine (not including the normally aspirated base V6).
Working out the kinks in the Silverado and Sierra's supply chain couldn't be more important to the health of the company. Full-size pickups are a huge profit driver - in 2012, the trucks were said to make up about two-third of GM's total profits.

GM's MPG overstatement could affect 2 million vehicles

Late last week, GM admitted that three of its large SUVs fuel economy window stickers did not match their actual efficiency ratings, and so the vehicles couldn't be sold. The stickers on the 2016 Chevy Traverse, GMC Acadia, and Buick Enclave said their ratings were one to two miles per gallon better than they should have been. Officially, the number of affected vehicles sits at about 60,000. But Consumer Reports makes a good point: what's up with all of the previous model year SUVs that are basically the same vehicle? To wit: the 2016 model year vehicles are not substantially different than the 2015 or the 2014, or even going all the way back to 2007. On the EPA's fuel economy website, all of these older models will "have better stated fuel economy numbers than the new vehicles in GM's dealerships," Consumer Reports noted. CR's best point, and the one that makes the 60,000 number potentially grow to 2 million if all of the vehicles built on this platform are affected, is that "[i]t seems unlikely that the company would change the powertrain on these carryover models so late in their model cycles in a way that would cause a dramatic, negative impact on fuel economy." GM says that earlier model year SUVs are not affected and the EPA did not respond to CR's question about the potential for more discrepancies. We've seen automakers reverse course before, so if GM has to come out with a mea culpa soon, don't be surprised. GM is rushing corrected stickers to dealers so that the SUVs can be sold again, but a fix for the already-sold vehicles could be trickier to solve. Related Video: Related Gallery 2013 GMC Acadia View 16 Photos News Source: Consumer Reports Government/Legal Green Buick Chevrolet GMC Fuel Efficiency mpg gmc acadia chevy traverse