When will the light duty V8 diesel show up? Mr. White says, “We’ll have one about the same time as everyone else.” He’s also mum on who GM will source the diesel from - whether it will be Isuzu, who supplies the current Duramax for use in the 2500 and 3500 class Silverado and Sierra, or from another supplier.
Mr. White did however tell PickupTruck.com about other GMT900 power and drivetrain news. If diesel prices rise too much and heavy duty buyers start to demand gas engine choices beyond the current 6.0-liter Vortec V8, don’t expect the big block 8.1-liter Vortec V8, discontinued this year, to return to the HD lineup. “We’d look at something other than the 8.1,” says Mr. White.
There’s no plan for GM to offer a dual mode hybrid HD pickup to help obtain improved fuel economy in the 2500 and 3500 models. Only a light duty hybrid will go on sale, by the end of calendar year 2008. But some hybrid technology will still trickle out to trucks with traditional internal combustion powertrains.
“We’re smoking everyone pretty good today in fuel economy,” says Mr. White. “From start to finish with the 800s we picked up 2 miles per gallon, and we picked up another two when we launched the 900s. We’re not going to stop. We’re going to continue to improve fuel economy every year for the life of the truck. We’ve got lots of stuff still coming and we’re going to show that performance and fuel economy don’t have to be mutually exclusive,” he says.
That future “stuff” includes more efficient oil pumps, fuel pumps, and replacing today’s hydraulic-based power steering systems with electrically powered steering (EPS) donated from the dual mode hybrid.
Conventional hydraulic power steering consumes more energy than electromechanical steering because the hydraulics require a constantly running pump, regardless of whether the vehicle is turning or moving in a straight line. Belt driven EPS, in contrast, requires no pump, hoses or fluid. Its power is applied directly to the steering system as needed to help the driver turn – resulting in about 10% of the energy consumption of a conventional steering system, which helps boost fuel economy. Up until recently EPS could only be used on small vehicles because the standard 12-volt power system found in most cars and trucks couldn’t power a big enough motor to assist the steering effort required turning large automobiles. But Mr. White says, “We’ve got some interesting technologies to get EPS costs way, way down to where you could put it across the board.” Could this mean we’ll see a 42-volt power system on all future trucks too, not just the two mode hybrid? We’ll have to wait and see.
In a change from previous reports about the timeline for six-speed transmissions to start showing up in GM’s half-tons, other than GMC’s Sierra Denali, Mr. White says, “We’ll probably roll out the six-speed earlier than 2009. You’ll see them in one model and then another.”
And as six-speed gearboxes deploy, the 367-horsepower / 375 lb-ft 6.0-liter Vortec Max V8 will be retired and replaced with the 403-hp / 417 lb-ft 6.2-liter Vortec V8 across the entire light duty lineup. Today it’s only found in the Sierra Denali. The 6.2 is the most powerful naturally aspirated V8 currently available in the half-ton segment.Page: