GM Reveals Small-Block V-8 with Direct Injection
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GM Reveals Small-Block V-8 with Direct Injection
http://subscribers.wardsauto.com/ar/...v-8/index.html
By Mike Sutton
Aug. 29, 2007
MILFORD, MI – Although General Motors Corp. is dividing its resources to cover all fronts of advanced powertrain development, the future of the auto maker’s foundation OHV small-block V-8 architecture appears secure with the advent of direct-injection gasoline (DIG) technology.
Among the various exhibits of engineering bravado on display at the auto maker’s proving grounds here, including two-mode hybrid-electric drivetrains, ultra-clean turbodiesels and homogeneous charge compression ignition flex-fuel engines, a seemingly untouched Cadillac Escalade stands out.
Emblazoned with giant E85 banners down its flanks, there is little to indicate the industry’s first OHV V-8 with DIG fueling lurks beneath the SUV’s pearl white hood.
The experimental engine is based on GM’s current all-aluminum Gen IV 6.2L V-8 (L92) found in the Escalade, GMC Yukon Denali and Hummer H2. Depending on the application, the powerplant, which sports port fuel injection, variable valve timing (VVT) and dual-cam phasing, is rated between 380-403 hp in stock form.
However, with a little tweaking to accommodate the auto industry’s latest fuel-injection hardware, the prototype V-8 is producing “well north of 450 hp (on gasoline),” says Dave Sczomak, development engineer-GM Powertrain Advanced Engineering.
Running the engine on E85 ethanol allows for even more power to be coaxed from the big V-8, he adds, noting the 85%/15% ethanol/gasoline mix generally carries a race fuel-like 106 octane rating.
Cruising the web of test roads onsite, the Escalade motors along smoothly with a characteristic large-displacement V-8 burble. However, mashing the gas from a standstill produces a wave of power that propels the big truck at a noticeably more rapid pace than the production version.
Along with the substantial increase in horsepower, DIG also contributes to about a 10% increase in low-end torque, Sczomak says. In addition, fuel economy is moderately improved (3-6%), as are cold-start emissions of hydrocarbons.
To accommodate the DIG fueling system, GM redesigned the L92 cylinder heads, rearranging the intake ports to make room for the eight high-pressure injectors that squirt fuel directly into the side of the combustion chamber at 2,250 psi (155 bar).
New dished pistons – similar to a diesel’s – were installed for added clearance of the injectors. They also contribute to a greater compression ratio (11.5:1 vs. 10.5:1), which can be employed because of the high-octane composition of E85 and the knock-reducing cooling effect of introducing fuel directly into the cylinder.
A modified engine controller manages the engine’s operation, while VVT and Active Fuel Management cylinder deactivation contribute to efficiency and refinement.
The development sounds like a no-brainer for improving nearly every aspect of the near-60-year-old small block’s performance.
However, Tom Stephens, group vice president-GM Powertrain and Quality, notes introducing a production DIG small block would “require the next-generation architecture” of the engine, or Gen V.
This primarily is due to the huge volumes of V-8 engines GM produces, Sczomak says, noting a radical change in cylinder-head design, for example, becomes a monumental undertaking when taking into account GM’s annual build of more than 1 million small block V-8s.
Fortunately, timing is on the auto maker’s side. The recent introduction of the ’08 Corvette’s 430-hp LS3 V-8, along with the release later this year of the ’08 Chevrolet Tahoe Hybrid’s 6.0L V-8, represent the last editions of the Gen IV engine family, Stephens says.
All subsequent introductions will be of the Gen V architecture and could have DIG fueling integrated from the ground up, especially considering the refinement of the current test engine’s operation. The greater specific output provided by DIG also would allow for greater engine downsizing, thereby improving fuel economy even further.
“GM would want to introduce this (DIG) on a high-profile vehicle, such as the new (Chevrolet) Camaro or (rear-wheel-drive) Impala,” Global Insight analyst John Wolkonowicz says, referring to the auto maker’s plans for new volume models based on its global RWD platform developed by GM Holden Ltd. in Australia.
The new Camaro, which originally was shown at the 2005 North American International Auto Show in Detroit, is expected to appear later next year as an ’09 model, with the all-new RWD Impala taking form sometime early in the next decade. Revisions for future generations of the Corvette and Chevrolet Silverado/GMC Sierra pickups are expected in the same timeframe, Wolkonowicz says.
By capitalizing on areas of significant improvement that remain untapped in its core engine lineup, while simultaneously amping up the arrival of its new hybrid-electric vehicles, clean diesels and hydrogen fuel cells, GM clearly is betting on an ever-fracturing market for advanced powertrains.
As a result, the iconic grumble of the small-block V-8 appears poised to remain a fixture of the automotive landscape for the foreseeable future.
By Mike Sutton
Aug. 29, 2007
MILFORD, MI – Although General Motors Corp. is dividing its resources to cover all fronts of advanced powertrain development, the future of the auto maker’s foundation OHV small-block V-8 architecture appears secure with the advent of direct-injection gasoline (DIG) technology.
Among the various exhibits of engineering bravado on display at the auto maker’s proving grounds here, including two-mode hybrid-electric drivetrains, ultra-clean turbodiesels and homogeneous charge compression ignition flex-fuel engines, a seemingly untouched Cadillac Escalade stands out.
Emblazoned with giant E85 banners down its flanks, there is little to indicate the industry’s first OHV V-8 with DIG fueling lurks beneath the SUV’s pearl white hood.
The experimental engine is based on GM’s current all-aluminum Gen IV 6.2L V-8 (L92) found in the Escalade, GMC Yukon Denali and Hummer H2. Depending on the application, the powerplant, which sports port fuel injection, variable valve timing (VVT) and dual-cam phasing, is rated between 380-403 hp in stock form.
However, with a little tweaking to accommodate the auto industry’s latest fuel-injection hardware, the prototype V-8 is producing “well north of 450 hp (on gasoline),” says Dave Sczomak, development engineer-GM Powertrain Advanced Engineering.
Running the engine on E85 ethanol allows for even more power to be coaxed from the big V-8, he adds, noting the 85%/15% ethanol/gasoline mix generally carries a race fuel-like 106 octane rating.
Cruising the web of test roads onsite, the Escalade motors along smoothly with a characteristic large-displacement V-8 burble. However, mashing the gas from a standstill produces a wave of power that propels the big truck at a noticeably more rapid pace than the production version.
Along with the substantial increase in horsepower, DIG also contributes to about a 10% increase in low-end torque, Sczomak says. In addition, fuel economy is moderately improved (3-6%), as are cold-start emissions of hydrocarbons.
To accommodate the DIG fueling system, GM redesigned the L92 cylinder heads, rearranging the intake ports to make room for the eight high-pressure injectors that squirt fuel directly into the side of the combustion chamber at 2,250 psi (155 bar).
New dished pistons – similar to a diesel’s – were installed for added clearance of the injectors. They also contribute to a greater compression ratio (11.5:1 vs. 10.5:1), which can be employed because of the high-octane composition of E85 and the knock-reducing cooling effect of introducing fuel directly into the cylinder.
A modified engine controller manages the engine’s operation, while VVT and Active Fuel Management cylinder deactivation contribute to efficiency and refinement.
The development sounds like a no-brainer for improving nearly every aspect of the near-60-year-old small block’s performance.
However, Tom Stephens, group vice president-GM Powertrain and Quality, notes introducing a production DIG small block would “require the next-generation architecture” of the engine, or Gen V.
This primarily is due to the huge volumes of V-8 engines GM produces, Sczomak says, noting a radical change in cylinder-head design, for example, becomes a monumental undertaking when taking into account GM’s annual build of more than 1 million small block V-8s.
Fortunately, timing is on the auto maker’s side. The recent introduction of the ’08 Corvette’s 430-hp LS3 V-8, along with the release later this year of the ’08 Chevrolet Tahoe Hybrid’s 6.0L V-8, represent the last editions of the Gen IV engine family, Stephens says.
All subsequent introductions will be of the Gen V architecture and could have DIG fueling integrated from the ground up, especially considering the refinement of the current test engine’s operation. The greater specific output provided by DIG also would allow for greater engine downsizing, thereby improving fuel economy even further.
“GM would want to introduce this (DIG) on a high-profile vehicle, such as the new (Chevrolet) Camaro or (rear-wheel-drive) Impala,” Global Insight analyst John Wolkonowicz says, referring to the auto maker’s plans for new volume models based on its global RWD platform developed by GM Holden Ltd. in Australia.
The new Camaro, which originally was shown at the 2005 North American International Auto Show in Detroit, is expected to appear later next year as an ’09 model, with the all-new RWD Impala taking form sometime early in the next decade. Revisions for future generations of the Corvette and Chevrolet Silverado/GMC Sierra pickups are expected in the same timeframe, Wolkonowicz says.
By capitalizing on areas of significant improvement that remain untapped in its core engine lineup, while simultaneously amping up the arrival of its new hybrid-electric vehicles, clean diesels and hydrogen fuel cells, GM clearly is betting on an ever-fracturing market for advanced powertrains.
As a result, the iconic grumble of the small-block V-8 appears poised to remain a fixture of the automotive landscape for the foreseeable future.
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Joined: Apr 2002
Posts: 384
From: Australia
Actually this article brings up some interesting stuff other than the DIG.
First if the LS3 is the last of the GenIV engines what about the LS8, LS9, LSA? Does this mean these engines are going to be GenV and therefore DIG standard? It would explain the reports of GM struggling to keep the power down on the blue devil....
Second, Who was it that said that the Camaro engines don't exist yet (awhile ago)......
Third,
First if the LS3 is the last of the GenIV engines what about the LS8, LS9, LSA? Does this mean these engines are going to be GenV and therefore DIG standard? It would explain the reports of GM struggling to keep the power down on the blue devil....
Second, Who was it that said that the Camaro engines don't exist yet (awhile ago)......
Third,
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From: The Golden State
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Awesome, but.....
Sounds like fantastic engines, and I'm a lifetime member to the "you can never have enough power" club, but....
...with times, sensibilities, and global outlooks changing, I'd much rather see power stay where it's at and milage increase substantially.
I don't mean to be a wet blanket, expecially with this crowd, but to me something truely Amercian would be a "400hp/35mpg highway" small block, literally demonstrating to the rest of the world how to have your cake and eat it too. I'm not an engineer, so perhaps with I.C. dynamics increased power with the same milage is the only advance that can be made.
Dunno, color me contrarian I guess.
...with times, sensibilities, and global outlooks changing, I'd much rather see power stay where it's at and milage increase substantially.
I don't mean to be a wet blanket, expecially with this crowd, but to me something truely Amercian would be a "400hp/35mpg highway" small block, literally demonstrating to the rest of the world how to have your cake and eat it too. I'm not an engineer, so perhaps with I.C. dynamics increased power with the same milage is the only advance that can be made.
Dunno, color me contrarian I guess.
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Joined: Jun 2003
Posts: 3,620
From: Saginaw, Michigan
Originally Posted by SSbaby
“GM would want to introduce this (DIG) on a high-profile vehicle, such as the new (Chevrolet) Camaro or (rear-wheel-drive) Impala,” Global Insight analyst John Wolkonowicz says, referring to the auto maker’s plans for new volume models based on its global RWD platform developed by GM Holden Ltd. in Australia.
Dan
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Joined: Aug 2007
Posts: 69
From: Philly Burbs, PA
Sounds like fantastic engines, and I'm a lifetime member to the "you can never have enough power" club, but....
...with times, sensibilities, and global outlooks changing, I'd much rather see power stay where it's at and milage increase substantially.
I don't mean to be a wet blanket, expecially with this crowd, but to me something truely Amercian would be a "400hp/35mpg highway" small block, literally demonstrating to the rest of the world how to have your cake and eat it too. I'm not an engineer, so perhaps with I.C. dynamics increased power with the same milage is the only advance that can be made.
Dunno, color me contrarian I guess.
...with times, sensibilities, and global outlooks changing, I'd much rather see power stay where it's at and milage increase substantially.
I don't mean to be a wet blanket, expecially with this crowd, but to me something truely Amercian would be a "400hp/35mpg highway" small block, literally demonstrating to the rest of the world how to have your cake and eat it too. I'm not an engineer, so perhaps with I.C. dynamics increased power with the same milage is the only advance that can be made.
Dunno, color me contrarian I guess.
5.3 sounds like the perfect size to slot below the LS3 outfitted high output trims?! This leaves a SC LS3 insane edition for those of you blessed with gold-trimmed wallets.
