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

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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.

wards auto.com

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Excellent...

But who wants to bet me that GM will be late to market with this technology?

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Excellent...

But who wants to bet me that GM will be late to market with this technology?

GM already has the technology out with the 08 CTS, they just don't have it out on a V8. GM doesn't have to play catch-up with their V8s, it's the V6s they are playing catch-up with.
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sweet. the small block lives on........

they should tune a DI version of the small block for fuel efficiency. imagine a simple small block in say, a zeta imapala, that if paired with a dual mode hybrid could get 40mpg highway and 30 in town......

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GM already has the technology out with the 08 CTS, they just don't have it out on a V8. GM doesn't have to play catch-up with their V8s, it's the V6s they are playing catch-up with.

CTS is DOHC, the V8's are OHV. they are different animals.

per FOG's comment, who else is going to get there first with DI in OHV?

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CTS is DOHC, the V8's are OHV. they are different animals.

per FOG's comment, who else is going to get there first with DI in OHV?

I don't think that's what he was referring to. The only other company that makes OHV is Chrysler. I don't see Chrysler introducing it first.
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Funny the article said 'near 60 year old small block'...that's a bit of exaggeration, since the SBC has been around a little over 50 years (1955) and the current Gen IV and Gen V have very little in common with the originals..

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I remember reading where Bob Lutz was disappointed that DI didn't improve mileage as much as they were hoping. But they were just putting DI on existing displacements. Normally, not always, smaller displacements get better mileage than larger displacements. Since mileage is going to be more and more of an issue, would you think that it would be smart for GM to down size their Gen V small blocks to put a bigger emphasis on mileage instead of the big power numbers? (Have roughly the same power levels of the Gen IV, but with better mileage.) They did down sized before when they went to the 5.3, but they still got a large increase in power. THis would distance themselves even more from the competition when it comes to mileage. Or should they go after the prize of most powerful?

What do you think?

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Excellent...

But who wants to bet me that GM will be late to market with this technology?

They'll probably be the only one with DI and OHV. Currently Audi, Lexus, BMW, Mercedes, VW, and Porsche have DI V8s.

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They'll probably be the only one with DI and OHV. Currently Audi, Lexus, BMW, Mercedes, VW, and Porsche have DI V8s.

I wonder when Ford will get in the DI V8 game...

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I remember reading where Bob Lutz was disappointed that DI didn't improve mileage as much as they were hoping. But they were just putting DI on existing displacements. Normally, not always, smaller displacements get better mileage than larger displacements. Since mileage is going to be more and more of an issue, would you think that it would be smart for GM to down size their Gen V small blocks to put a bigger emphasis on mileage instead of the big power numbers? (Have roughly the same power levels of the Gen IV, but with better mileage.) They did down sized before when they went to the 5.3, but they still got a large increase in power. THis would distance themselves even more from the competition when it comes to mileage. Or should they go after the prize of most powerful?

What do you think?

well... direct injection isnt linked to any performance features... the only thing direct injection actually does is provide means to cooler fuel... allowing the fuel to withstand a few more points of compression... this allows the fuel to ignite properly at higher compressions, allowing for more power per unit of fuel... but thats based on extra compression, not more fuel usage... so, technically it could make a smaller engine capable of equal power, so less usage, but currently they've just added the technology to increase compression, in years to come they will probably reduce the size of each motor by say, .2-.5 liters to adjust to upcoming fuel standards... and maintain previous horsepower rates

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I wonder when Ford will get in the DI V8 game...

There have been rumors of a DI twin turbo Boss V8 for the full size trucks at BON as a lower cost alternative to the diesels.
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Imagine what the DI can do to the Corvette...

doubt it would have much effect... the corvette is already the benchmark for gm's engine, valvetrain, and fuel efficency...

the corvettes horsepower per unit of fuel is by far the greatest in the automotive world...

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well... direct injection isnt linked to any performance features... the only thing direct injection actually does is provide means to cooler fuel... allowing the fuel to withstand a few more points of compression... this allows the fuel to ignite properly at higher compressions, allowing for more power per unit of fuel... but thats based on extra compression, not more fuel usage... so, technically it could make a smaller engine capable of equal power, so less usage, but currently they've just added the technology to increase compression, in years to come they will probably reduce the size of each motor by say, .2-.5 liters to adjust to upcoming fuel standards... and maintain previous horsepower rates

Are you sure about the cooler fuel? I thought it was cooler cylinders that enabled them to increase the compression and the cooler cylinder was caused by the better mixture of air and fuel. And with the higher compression ratio, that of course would increase it's combustion efficiency. I think I just repeated you in my own words, I guess. It's just the cooler fuel part where I think we differ.

And DI effect on the Corvette. How could it not? The benchmark is always rising.

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Death of the V8, my ass!

Over one million produced each year?

This kind of tech advancing the world's most successful powerplant several times per generation?

Damn!

Was a certain former poster waaaay off base. :lol:

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Hmmmm, showing off DI technology in V-8's? This could be 2 years out, if that. A DI Corvette would rock, or a DI Camaro? DI Silverado? DI Tahoe? DI Suburban? DI Escalade? DI Enclave V-8? :drool:

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What if GM offered ....

V-8

E85-Capable

Direct Injected

All Aluminum

VVT

300 hp

300 lbft torque

6-speed transmission

25 city / 30 highway

Would there be a market for a truck like that?

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Dude, very cool! I seriously hope they get this out soon to stomp any foreign V8s that are coming...

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Are you sure about the cooler fuel? I thought it was cooler cylinders that enabled them to increase the compression and the cooler cylinder was caused by the better mixture of air and fuel. And with the higher compression ratio, that of course would increase it's combustion efficiency. I think I just repeated you in my own words, I guess. It's just the cooler fuel part where I think we differ.

And DI effect on the Corvette. How could it not? The benchmark is always rising.

sure all i know is its helps to reduce temperatures, so that the compression can heat it back up again, but Direct injection is old technology...

i would highly doubt gm would offer technology first on their cobalts and cts's before they offered it on the corvette if it indeed was going to improve performance on the ls2/ls7...

put perhaps... think the LS2 already runs rather high compression, not as high as the others...

i beleive the tahoe hybrid is a direct injection... but i could be wrong

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Death of the V8, my ass!

Over one million produced each year?

This kind of tech advancing the world's most successful powerplant several times per generation?

Damn!

Was a certain former poster waaaay off base. :lol:

The context was V8s for everyday sedans—CTS, STS, 5-Series, E-Class, Impala etc.. Increasing performance of 4- and 6-cylinder engines would render the V8 a solely niche product in cars (not trucks): i.e. only in top end vehicles such as the M3, S4, Corvette etc.. would there be any real market for a V8 engine.,
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The context was V8s for everyday sedans—CTS, STS, 5-Series, E-Class, Impala etc.. Increasing performance of 4- and 6-cylinder engines would render the V8 a solely niche product in cars (not trucks): i.e. only in top end vehicles such as the M3, S4, Corvette etc.. would there be any real market for a V8 engine.,

I think he was referring to non-luxury cars also.
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I remember that defense of the title very well, and it rings even more empty now than it did then.

Witness:

Camaro

Impala (current and upcoming)

G8

Ute

Lucerne

Monte Carlo

and so on...

Even if you restrict the title to "Death of the v8 in average family sedans", it doesn't hold much value.

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What if GM offered ....

V-8

E85-Capable

Direct Injected

All Aluminum

VVT

300 hp

300 lbft torque

6-speed transmission

25 city / 30 highway

Would there be a market for a truck like that?

There would be a market for a truck like this. With that power rating, I think it would be a Colorado/Canyon sized pickup truck, and with mileage like that, they would sell a ton of them if the quality and reliability was there.

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