2004 Chevrolet Colorado Z71 Ls Crew Cab Pickup 4-door 3.5l 4wd on 2040-cars

Auto blog

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

Chevy says not to look at the 2019 Silverado's fuel economy rating

The 2019 Chevy Silverado is hitting dealerships soon, and one of the most notable changes for the new full-size pickup is the addition of a 2.7-liter turbocharged inline-four. The engine replaces the naturally-aspirated 4.3-liter V6 in volume consumer models like the Silverado LT and promises more power, less weight and — most importantly — better fuel economy. The thing is, the gains in efficiency haven't been as dramatic as some might have hoped, especially when stacked up against competitors from Ford and Ram. As Automotive News reports, GM's response is a little murky. First, let's talk numbers. We're pulling all figures from FuelEconomy.gov, the official U.S. government source for fuel ratings. Fuel economy numbers on trucks vary greatly based on a number of factors. Bed and cab configuration play a part, but so does a four-wheel-drive system. You also have to factor in tires, transmissions, rear-axle gearing, hybrid systems and cylinder deactivation. Things like that can make the difference between best- and worst-in-class. The EPA's website doesn't give enough information a lot of the time, so there's really no easy way to compare apples-to-apples. First, take a look at the ratings for the 2019 Silverado. A 2.7-liter model with two-wheel drive is rated 20 city, 23 highway and 21 combined. That's both better and worse than a two-wheel drive 2018 Silverado with the 4.3-liter V6 (18 city, 24 highway and 20 combined). The updated 2019 Silverado with a 4.3-liter V6 has yet to be rated. With less weight and a smaller engine, many hoped Chevy would make bigger gains. It's unusual to see any decrease in a fuel economy metric these days. GM says that it's not done tuning the new 2.7-liter engine, so fuel economy could theoretically increase. Expanding further, a V8-powered 2019 Silverado (17 city, 24 highway and 19 combined) actually gets better highway fuel economy than a turbocharged four-cylinder powered truck in certain configurations, even if the latter has a better overall average. But that's only with two-wheel drive, the 8-speed transmission and cylinder deactivation. A Silverado with the 5.3-liter V8 and a 6-speed automatic is rated at 15 city, 22 highway and 17 combined. The biggest issue with the Silverado 2.7-liter doesn't come from within GM itself but from Ford and Ram. GM cites the Ford F-150 with the 3.3-liter V6 and the Ram 1500 with the 3.6-liter V6 as the closest competitors to its new 2.7-liter inline-four.

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.