Auto blog

'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).

GMC Terrain's first generation could get recalled for headlights

According to Car Sales Base, GMC sold 745,454 Terrain crossovers from the end of 2009 to the end of 2017, all but a few of them representing the first-generation model years of 2010 to 2017. According to the National Highway Traffic Safety Administration, the carmaker will need to recall almost all, due to a problem with excessively bright headlight reflections. NHTSA takes issue with the fact that federal motor vehicle regulations stipulate how bright headlight reflections are allowed to be within a certain arc of the headlight beam axis. In a certain area of the arc, the Terrain throws two small spots of light that are about 450 to 470 candela strong where the legal maximum at that point is 125 candela — one candela being equivalent to the light from one candle. The NHTSA wants the headlights replaced for being close to four times over this reflective limit, alleging this can cause "glare to other motorists driving in proximity." GM discovered the noncompliance in 2019, then filed a notice of noncompliance that requested an exemption from having to recall the crossover. GM's counterpoint to NHTSA was that the two areas of illegality were 80 degrees outboard of the headlight and 45 degrees up. You'd have to be Slenderman or a giraffe standing on the side of the road — our words, not GM's — to be blinded by the light. The automaker hadn't heard of any incidents nor complaints over the issue. The only customer feedback GM received was a Terrain driver saying the "left headlamp seems to have a portion of the light that shines up in the trees at near a 45-degree angle." Note, that's the left headlight, so the tree in question would likely be on the other side of the road. GM said oncoming traffic wasn't impaired by the excessive brightness. Due to these these mitigating factors, GM asked for an exemption from recalling the Terrains.    This week, NHTSA denied GM's petition.

GM recalls full-size truck, SUVs and vans over faulty shifter mechanism

Twelve different General Motors vehicles from the 2013 model year, up to 54,686 units in total, are being recalled over two potential issues with their steering columns. The models in question, all full-size trucks, SUVs or vans, are the: Cadillac Escalade, Escalade ESV, Escalade EXT, Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, and GMC Savana, Sierra, Yukon and Yukon XL.
The affected vehicles were built with a fractured parking lock cable or "a malformed steering column lock actuator gear in the lock module assembly." As a consequence, they could shift out of park without the brake pedal being applied or with the key removed or in the off position.
A bulletin from the National Highway Traffic Safety Administration indicates that the recall should begin on January 17. GM will notify owners, at which time they can take their vehicles to their dealers for repair free of charge. Have a look at the bulletin below for more information.