GM Reveals Small-Block V-8 with Direct Injection - wardsauto.com

[lusterblade]

GM Reveals Small-Block V-8 with Direct Injection - wardsauto.com
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.

[SuperSS27]

Yes!!! Finally intorduction of High compression engines with E85 and direct injection. This is going to be the new thing for GM to trump everyone else on.

[unkillsam]

Originally Posted by SuperSS27

Yes!!! Finally intorduction of High compression engines with E85 and direct injection. This is going to be the new thing for GM to trump everyone else on.

He mentions the Camaro.

How cool would it be if the Z28 was introduced with a 5.0 (302) LS motor making 350-375 horsepower with 30 mpg.

[Michael_S]

So the prototype 6.2 for the Escalade is producing over 450 horsepower (at least 12% above the standard engine's 403 horsepower) and 10% more low end torque (although not necessarily 10% more peak torque, as the 6.2 makes peak torque at a relatively high 4300 RPMs) while getting 3-6% better fuel economy.

That's absolutely outstanding. It looks like a Gen V smallblock Vortec 5300 with direct injection would be every bit as powerful as the current Vortec Max.

Hopefully the LS engines get a similar power bump.

[unkillsam]

Originally Posted by Michael_S

So the prototype 6.2 for the Escalade is producing over 450 horsepower (at least 12% above the standard engine's 403 horsepower) and 10% more low end torque (although not necessarily 10% more peak torque, as the 6.2 makes peak torque at a relatively high 4300 RPMs) while getting 3-6% better fuel economy.

That's absolutely outstanding. It looks like a Gen V smallblock Vortec 5300 with direct injection would be every bit as powerful as the current Vortec Max.

Hopefully the LS engines get a similar power bump.

That's so true. Hopefully there are no plans to add DI to the Tundra any time soon.

[SuperSS27]

Originally Posted by Michael_S

So the prototype 6.2 for the Escalade is producing over 450 horsepower (at least 12% above the standard engine's 403 horsepower) and 10% more low end torque (although not necessarily 10% more peak torque, as the 6.2 makes peak torque at a relatively high 4300 RPMs) while getting 3-6% better fuel economy.

That's absolutely outstanding. It looks like a Gen V smallblock Vortec 5300 with direct injection would be every bit as powerful as the current Vortec Max.

Hopefully the LS engines get a similar power bump.

I dont see why they wouldn't get a similar power increase. Even if they do it for just the gas mileage increase, it would be worth it.

[supraracer]

Sweet!

[vdoh182]

Direct Injection is well suited to forced induction, isn't it. I wouldn't be surprised to see this in the technology in the blue devil or CTS-V (a DI LS7 would probably rape, well, everything).

[nsap]

Awesome news. It sounds like GM is getting ready to get back at Toyota for the Tundra 5.7.

[CBECK]

Nothing beats a GM V-8. And it looks like nothing going to change.

[jkennedy293]

I love the possibility of a Yukon with a 5.3L DI engine and Hybrid drivetrain. This combo could realistically make 30mpg on the highway, and you would still be able to tow a decent sized boat.

[Z06ified]

E85 and DI are making for a good combination. More power, cleaner air, fuel from a renewable home grown resource, and being able to tell the oil rich Arabs to go eat sand are all wonderful things.

[mbukukanyau]

Lets have that DOHC vs. OHV arguement. This is great.

[kodos78]

Very cool. GM once again proves it is the master of the small block V8.
Big power + great fuel efficiency.

What's not to love?

Don't mind my puny 300hp 4.6L. Gah, I wish Ford were more competitive in this area!

[JBsZ06]

With the pontiac solstice GXP having Direct Injection I was wondering when it would hit the Corvette.

450hp in the base vehicle would be awesome. Assuming the 40 extra hp the cadillac CTS has over the port injection version of the 3.6 ..theorically the base covette could move from the already impressive 436 hp to 476 hp..

I'd buy one.

Thnaks for the headsup.