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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 mulling off-road variants of fullsize SUVs

According to General Motors, owners "just love off-roading with [its fullsize body-on-frame sport utility vehicles]," namely the 2015 Chevrolet Tahoe and Suburban and GMC Yukon. If that's the case, it's a bit odd that sales of the previous generation of these models with the Z71 off-road package didn't sell particularly well.
Perhaps, considering this disconnect between owner's thoughts and desires with actual sales, it's not surprising that General Motors is reportedly "considering" an off-road specific model. That means the package would include styling changes and badges along with suspension modifications and larger wheels with appropriately sized fender flares.
There's no indication if the off-road model would be called Z71 or when it may potentially go on sale, assuming it ever goes on sale at all.

GM recalls Chevy Express, GMC Savana over rollaway concern

The National Highway Traffic Safety Administration has issued a recall notice for a small number of General Motors fullsize vans due to possible rollaway concerns. On certain 2013 Chevrolet Express and 2013 GMC Savana models, it is possible to remove the key from the ignition without the shifter being in park.
Only 980 total units are being affected by this recall, and GM is fixing the issue by replacing the ignition cylinder and associated keys. Affected Chevy vans were built during most of November and December while its GMC counterpart was only built for a week in November. The recall goes into effect on January 23, and to find out if your vehicle applies to the recall, the GM and NHTSA contact numbers can be found on the official recall notice, which is posted below.