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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 recalls 8,500 Chevrolet Malibu models for rear suspension glitch

According to a letter from General Motors to the National Highway Traffic Safety Administration, flaws in the build process of the 2013 Chevrolet Malibu have led to the recall of 8,519 cars. Units built between December 6, 2011 and January 15, 2013 may have been assembled with rear suspension cradles that had insufficient torque applied to certain bolts. That out-of-spec assembly could lead to issues ranging from slight noises to a loss of vehicle control.
The problem was first noticed in December of last year by a GM test fleet driver and eventually tracked back to the improperly torqued bolts on the suspension cradle assembled through July 2012 by a supplier located not too far from the Malibu's Detroit/Hamtramck Assembly Plant. Since an official NHTSA recall notice has not been issued yet, it isn't clear whether or not Detroit-built Malibus were the only ones affected (the 2013 Malibu is also built at GM's Fairfax Assembly Plant in Kansas City, Kansas). Dealers will fix the problem by inspecting vehicles for proper torque specs, retightening if not within specs and, in some cases, perform a rear-wheel alignment.

2015 Chevy Volt gets larger battery, though range remains the same

The Chevrolet Volt isn't changing much for the 2015 model year. According to specifications uncovered by Inside EVs, though, the new Volt's battery does have a slightly larger capacity. According to the spec sheet, this doesn't translate to increased range. Real world driving, though, might tell a different story. The 2015 Volt's battery storage is slightly higher than the outgoing model's, up from 16.5 kilowatt-hours to 17.1 kWh. According to GM's manager of electrification technology communications, Kevin Kelly, speaking to Green Car Reports, the increased capacity is "a late change done in the cell... just another continuous improvement to surprise and delight our customers." The stated electric range, however, stays at 38 miles. Inside EVs followed up on its original report, and found that drivers could see some advantage to the battery tweak. When they spoke to Kelly, he told them, "As a result of this change, we would expect that some customers may see a slight improvement in overall EV range." It's worth noting that when battery capacity increased from 16 kWh to 16.5 kWh for the 2013 Volt, electric range increased by three miles to the current 38, while MPGe went from 94 to 98. The price of the 2015 Chevrolet Volt remains steady, at $34,995. The actual cost to the customer is considerably less with the $7,500 federal tax credit, as well as any local incentives.