2013 Chevrolet Tahoe Ls on 2040-cars

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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:    

Next-gen Chevy Camaro ZL1 teases big changes under its camo

With work complete on the lighter, stiffer 2016 Camaro, it's time for Chevrolet's engineers to really start having fun by developing the next, ZL1 version. Here it is for the first time. Unfortunately, the muscle car is still wearing quite a bit of camouflage, but the concealment isn't enough to hide some of the meaner model's more obvious performance tweaks. Starting from the front, this Camaro now wears a much more aggressive front fascia with bigger air inlets. Managing the airflow around the engine bay is clearly a big deal because another photo reveals a fairly large extractor in the hood, as well. Moving down the profile, the lower side sills and orientation of the camo suggest some blistered fenders in the back to cover wider rubber, and at the very rear a much larger wing further suggests the need to keep things planted to the road. Check out the comparison images in the gallery for a better look at the tweaks. What will power the next ZL1 is still entirely a mystery, although sticking with a supercharged 6.2-liter V8 could be a possibility, especially if you take the big extractor in the hood as a hint. Whereas the current ZL1 makes 580 horsepower and 556 pound-feet of torque, the LT4 in the latest Cadillac CTS-V pumps out 640 hp and 630 lb-ft. Combined with the Camaro's other improvements, we're thinking that this new ZL1 will be quite a hot ticket, and based on these spy shots, we can't wait to find out.

2015 Callaway Corvette Z06 gets new supercharger, adds $17K to starting price

Callaway's proud tradition of modifying Chevrolets is about to add a very significant chapter this weekend, as the company prepares to unveil a modified version of the 2015 Corvette Z06. The engine mods are simple, though we expect them to be very potent. That's because Chevy has replaced the factory supercharger with a new "GenThree" unit that's nearly a third larger than what's bolted on in Bowling Green. A new intercooler is also added, along with a new high-flow intake system. Beyond that, the changes are exclusively of the subtle cosmetic variety. There's new badging inside and out, as well as new engine covers, floormats and an underhood plaque. Naturally, there's documentation to verify the Callaway Z06's authenticity, and the comfort that comes with a three-year, 36,000-mile warranty. Callaway has priced the upgrade package at $16,995, in addition to the price of the stock Z06. While we're still waiting to hear official power figures, that seems like a reasonable asking price for what were wagering will be a major increase in power. The Callaway Z06 will debut this weekend at the National Corvette Museum's C7 Bash in Bowling Green, KY. Expect more details following the debut. Scroll down for the official press release. Related Video: 2015 Callaway Corvette Z06 to Debut at National Corvette Museum The 2015 Callaway Corvette Z06 will debut at the National Corvette Museum C7 Bash in Bowling Green, Kentucky, April 23 through April 25. Here's a sneak peek at the new package. Based on Chevrolet's track-proven Z06, Callaway engineers' no-compromise approach takes this Corvette to an astounding power level. While advertised Callaway horsepower and torque are pending final validation, the Callaway package adds Callaway's new GenThree supercharger system with 32% more displacement than the stock Z06 supercharger, improved manifold design and unique triple-element intercooling system. Callaway engineers recognize that a key contributor to maximizing power is reduction of inlet air temperature. By exposing the supercharger's large plenum area to outside ambient airflow, the design takes advantage of the significant charge air temperature reduction provided by convective cooling. The completely redesigned intercooling system also helps maintain nearly ambient charge air temperature with exceptionally low air restriction.