Rotisserie Resortation - Modification - Panty Dropper - on 2040-cars

Auto blog

Why an independent rear suspension for GM's new, full-sized SUVs wasn't easy

A Motor Trend report last month laid out how Cadillac's 4.2-lier twin-turbo Blackwing V8 could be an orphan due to cost concerns in the GM empire. Last-minute chassis changes to Cadillac's new sedans and XT6 crossover led to engine bays that couldn't fit the Blackwing. On the SUV side, according to the report, the new independent rear suspension for big people haulers cost so much to implement that GM ruled out reworking the Escalade to accept the Blackwing. At least one commenter rightly asked how could a suspension swallow that much money. A new piece in Motor Trend has the answer. The excellent Alissa Priddle spoke to Tim Herrick, GM's executive chief engineer for full-size trucks, about why the clean-sheet IRS cost "multimillions of dollars."  First, GM would need to build a new body shop at the Arlington, Texas plant that assembles the automaker's big SUVs to stamp the numerous wholly new parts and panels accommodating an IRS. Then GM would need to design and pay for a new assembly process. On top of those up-front costs, there was the incremental cost of the four-link IRS components being more expensive than those in the trucks' former leaf-sprung solid axles. Herrick endured so many rejections for so long that he remembers the date and time when he got approval for the new unit. He said it came down to a meeting where he told a higher-up, "I'll make you a deal: If we get to the reveal, or if we launch this and you think this was a dumb idea, I'll hand you my badge and let you walk me out." Head to Motor Trend to read the full story. Based on Herrick being on stage to help present the new SUVs to the press, and on our First Ride in the new Chevrolet Tahoe and Suburban at GM's Milford Proving Grounds, it appears this will have a happy ending for all involved. Furthermore, since Herrick worked on the T1 platform that supports the big SUVs as well as the light- and heavy-duty pickups, he understood the demands on the commercial side, too. That could be why when Roadshow asked Tim Asoklis, chief engineer of the Tahoe and Suburban, if the new IRS could endure life in the Chevrolet Silverado and GMC Sierra, Asoklis answered, "Oh, absolutely." Related Video:    

GM patent reveals new two-stage turbocharger

Modern turbochargers may be some of the best ever made, but performance is something that engineers are always trying to improve. According to GM Inside News, General Motors (GM) is hoping to alleviate some of the negative aspects of a two-stage turbocharger setup with a newly-patented design. The patent, that was filed on May 19, 2016, reveals a clever bypass system that allows the engine, a four-cylinder unit, to optimize both the low-pressure and high-pressure inlets for its respective functions. According to the filing, a conventional two-stage turbocharger setup is engineered to allow both turbines to operate simultaneously at low and mid engine speeds. At high engine speeds, only the low-pressure turbine works. The setup can't isolate either the low or high pressure side, which can impair low-end performance. GM's new two-stage turbocharger setup looks to eliminate this by linking the high-pressure turbo to the exhaust manifold through the high-pressure inlet duct. The low-pressure turbo is attached to the high-pressure turbo by a low-pressure inlet duct, which is linked to a connecting channel. A single actuator that is housed in the exhaust manifold creates a bypass that can opens the high-pressure inlet or close the connecting channel. Depending on what the engine load and speed is, the ECU guides the actuator—a single rotating spindle with discs corresponding to flanges on the high and low pressure sides—to isolate one of the two turbos. Isolating the turbos allow the respective inlets to be engineered for the best possible fluid dynamic performance. The setup should increase performance and decrease lag. There's no word on what car this setup will make an appearance on, but it will most likely be used in premium vehicles before trickling down to the rest of GM's vehicles. Related Video: News Source: GM Inside News, AutoGuide via GM Authority Cadillac Chevrolet GM Technology Sedan turbo patent engine turbocharging

2022 Chevy Tahoe, Suburban and GMC Yukon get updated transmission

General Motors' full-sized SUVs have slipped in one more change before the year turns. GM Authority reports that the 2022 Chevrolet Tahoe and Suburban, and the 2022 GMC Yukon and Yukon XL equipped with gas V8 engines, will pick up a revised ten-speed automatic transmission. The new unit carries RPO code MHS, and Chevrolet communications rep Catherine Scales told GMA the updated gearbox "allows our manufacturing and dealer teams to more easily align the specific calibration needed for the transmission and can enable OTA updates in the future." It seems GM wants to make it easier to update the transmission's tuning and calibration in the future with the automaker's networked Vehicle Intelligence Platform/Global B electronic architecture. The 10-speed auto comes bolted to the 5.3-liter V8 and the 6.2-liter V8. The 3.0-liter inline-six Duramax diesel continues with the 10-speed automatic already in use. To recap the other changes for the full-sizers, we'll start with the 2022 Tahoe and Suburban, which get a new 12.3-inch digital instrument display to replace the former 8-inch unit and physical gauges. Navigation will be standard equipment displayed on the 10.2-inch infotainment touchscreen on all trims barring the base LS. Lane-keeping assist and parking sensors are also now standard, while reverse automatic braking is added to the Enhanced Display and Alert package on the top trims. Finally, the 6.2-liter V8 option is expanded to the Z71, RST and Premier trim levels, but it requires selecting one or more packages on the Z71 and RST. Moving onto the 2022 Yukon, availability of the 6.2-liter V8 expands to the AT4 trim, and the big V8 comes with a shiny pair of exhaust finishers. Redwood Metallic paint joins the exterior color palette, more wheel options are on offer, and illuminated sill plates can gussy up the rocker panels . An Enhanced Trailering Technology Package adds 13 cameras with the option for an interior accessory camera for those with enclosed haulers. On the safety side, expect reverse automatic braking to join the list of available driver assistance features. Inside, the Yukon welcomes the 12.3-inch digital cluster, the Yukon Denali welcomes the power sliding console as a standard feature instead of a $350 option.  Related Video: