2007 Gmc Sierra 3500 Crew Cab Diesel Dually W/auxiliary Fuel Tank on 2040-cars

Auto blog

Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.

Chevy and GMC trucks get CNG option pricing

Chevrolet and GMC have clued us in to pricing of the bi-fuel option for the 2015 Silverado and Sierra 2500HD CNG and 3500HD CNG pickups: it starts at $9,500; we're still missing the rest of the pricing inferred by the word "starts," however. If you remember from the Chicago Auto Show introduction, the 6.0-liter V8 puts out 360 horsepower and 380 pound-feet of torque when drinking gas, 301 hp and 333 lb-ft when inhaling CNG.
Chevrolet figures that a bi-fuel Silverado HD is worth $2,000 in savings if driven 19,500 miles on CNG and 7,500 miles on gasoline in the span of a year, a recoup rate easily attainable to high-mileage fleet owners. It can be specced on double- and crew-cab pickups with single rear wheels, not on dualies.
The 2015 Chevrolet Express and GMC Savana short-wheelbase passenger and cargo vans also get CNG options, starting at $10,825 for the three-tank system, and $12,090 for the four-tank system that can only be had on the cargo hauler. You'll find a bit more info on all of the permutations in the press release below.

2013 GMC Acadia Denali

Refreshed, Not Refreshing
I'm probably ill-suited to accurately and fairly take the full measure of a vehicle like the 2013 GMC Acadia Denali. This is a machine conjured around the express notion of corralling and then herding a brood of rafter-swinging hatchlings to and fro in relative comfort, and with no such passel of wee Bowmans to call my own, it's difficult to give this rig a fair shake. While I can certainly weigh cargo capacity, legroom and fuel economy stats with the best of them, I'd be lying to your face if I said the word "crossover" didn't urge some uncontrollable Pavlovian recoil from the murky recesses of my frame. To put it simply, I just can't stand the damn things.
As a rule, the segment is built on a bed of compromise. Manufacturers love nothing more than to spin up a tired yarn about the virtues of this particular neck of the market. We're told the crossbreeds deliver all the ride quality, driving dynamics and fuel economy of a car married with the seating position, capability and interior volume of the SUV set. That all sounds as swell as a sunset, but as the 2013 Acadia Denali so artfully illustrates, the advertising on the box is rarely congruous with the prize inside. Even with an imaginary squad of younglings at my heels, the refreshed luxury crossover doesn't quite manage to scratch the promised itches.