Automakers have employed cylinder deactivation for years now in an effort to increase fuel economy on large-displacement engines. The process essentially cuts fuel to a set number of cylinders when load on drivetrain is at minimal levels. But what if every cylinder could be deactivated to save fuel, only getting fuel and a spark when it’s needed? That’s what General Motors is exploring with the help of a company called Tula Technologies.
It’s called Dynamic Skip Fire and it basically uses sophisticated computer algorithms to fire only cylinders when needed for generating power and canceling vibrations caused by an imbalance in rotational mass. Though still in development, Tula claims a 15-percent improvement on fuel economy over V-8 engines with GM’s cylinder deactivation technology called Active Fuel Management.
Of course, DSF only works on engines with direct fuel injection like GM’s latest EcoTec3 family of engines.
Modifications to the engine include fully deactivatable lifter on the intake and exhaust valves, along with additional oil galleries in the block to supply the new lifter oil manifold assemblies with a steady steam of oil. The computer does the work beyond that.
No doubt the integration of DSF into a production engine will take time and thousands more hours of testing, but the idea of saving another 15 percent on fuel consumption without sacrificing peak engine output is a tantalizing thought. Hopefully we’ll see more of this system in the future, especially now that GM Ventures has announced its investment into Tula.
Click past the jump for more information
Unlike other oversized pickup trucks, the GMC Topkick had a pretty long life span. The vehicle is basically a rebadged version of the Chevrolet Kodiak and was sold until 2009.
The Topkick pickup was a medium duty truck designed to be able to deal with those loads that were too heavy for a conventional pickup truck and its 6.6 liter V8 unit can tow up to 16.000 pounds.
The vehicle was modified in 2003, when it received a series of new features, some exterior changes and upgraded technologies. The new truck came with both 4x2 and 4x4 configurations and had a starting price of $55.000.
Even since its first launch in 1996, the GMC Savana managed to attract buyers’ interest and for many years was the second best sold van from the US market, after the Ford E Series.
The van received a set of significant modifications in 2003 when it came with upgraded engines and a few style modifications.
The year 2003 has seen the introduction of a four wheel drive system that was a premiere for the Savana. The 2003 GMC Savana was also offered for the first time with four wheel disc brakes.
New driver-side 60/40 access doors have been added as an option together with larger stabilizer bars and a stronger frame. The cabin was slightly revised as well and Chevrolet added new seats, upgraded the lighting and ventilation systems, and also offered dual-stage airbags.
The GMC Savana shared the same design and underpinnings with the Chevrolet Express and was launched for the first time in 1996 as a replacement for the old GMC Vandura.
Thanks to its generous payload capacity and the strong engines, the vehicle was fairly practical and even since its debut, has managed to stay on top of the sales charts.
The van was build with versatility in mind and thanks to its flexible character in could’ve be converted into various commercial vehicles being perfectly suited to be used as an ambulance or bus.
The GMC Savana was offered with a choice of redesigned Vortec petrol engines which developed between 220 and 290 hp. There was also a 6.5 liter turbo diesel V8 unit which came with 190 hp on tap. The van is offered with two wheelbases, three gross vehicle weights and an Extended version.
After it was completely redesigned in 1999, the GMC Sierra has benefited from a few upgrades in 2003. With this occasion, the vehicle received a bolder front end and a few interior modifications.
There were also offered new comfort features which included a new sound system and an optional rear seat DVD entertainment center. Other upgrades were made to the brakes, while the engines were also slightly tweaked to run cleaner.
The entire engine lineup however, remained unchanged and the Sierra continued to be powered by the same units as the old generation.
The 2003 GMC Sierra continues to share the same underpinnings with its Chevrolet Silverado twin, but it’s considered slightly more upscale as it has more luxurious features than its brother.
Between GMC and Chevrolet there was always a strong bound, as these two brands shared a lot of platforms and technologies. It’s the same case for the Sierra truck that even since its inception shared the same design and engines with the Silverado.
A new generation Sierra was launched at the same time with the first Silverado pickup in 1999 and both models were based on the old Chevrolet C/K pickup.
The new Sierra represented a huge step forward in terms of engines and technology, undergoing a lot of upgrades which helped it climb to the top of the pickups food chain.
The 1999 GMC Sierra was offered with a new family of V8 engines and also some upgraded old units. There were various configurations available including regular or extended cabs, short bed or long bed, three trim levels and rear- or four-wheel-drive versions.
The GMC Sonoma was commercialized between 1994 -2004 and served as a base for all the following midsized pickups designed by the company.
The truck had a competitive price, was pretty efficient and was also highly versatile being able to cope with a wide range of arduous applications.
The Sonoma was built in two generations and the second generation can be still seen today, in isolated corners doing some heavy duty jobs.
The old GMC Sonoma however, wasn’t at the same level with its Japanese rivals and this is one of the reasons which made GMC realize that it should leave this model behind and move on.
The latest generation GMC Sonoma was offered in regular, extended and crew cab bodies with short and long beds. Engine choices included a 2.2-liter four-cylinder (118 horsepower), a 4.3-liter V6 (165 hp) and the Vortec 4.3-liter V6 (195 hp).
The GMC Canyon is the rebadged twin of the Chevrolet Colorado and shares every bit of technical and design detail with its sibling. The latest model was launched back in 2004 but, during the years it received a few small upgrades to help it deal better with competition. Though, GMC decided to replace the vehicle in 2013 as despite the continuous upgrades it remained behind its rivals it terms of style and technology.
Similarly with the Chevrolet Colorado, the GMC Canyon is offered with three engines which develop 185 hp, 242 hp and 300 hp with three body styles including regular cab, extended cab and crew cab configurations.
GMC’s vehicles have been around since the begging of pickups history and the newest model in the company’s lineup bears the name Sierra.
The old Sierras were capable workhorses, but were devoid of a proper cabin and the overall build quality was more on the poor side of things. The new generation however (launched in 2011) is a big improvement over the old ones as the vehicle managed to keep its work horse character and to also offer a high class cabin with a decent build quality and adequate comfort.
The GMC Savana is a rebadged version of the Chevrolet Express and is available in two trim levels naming the LS and LT. The chassis cab version of the model can be ordered with both rear-wheel-drive or full-wheel-drive configurations, and thanks to its solid chassis the vehicle can be used for a wide range of light-duty missions. The truck is powered by an inefficient but strong V8 engine and has a GVWR (gross vehicle weight rating) of 12,300 pounds pounds. The GMC Savana received its latest significant updates in 2009 and with a MSPR of $27,780 is among the most affordable cutaway models from the market.