There must have been a minor change to the power train in the 2009 G8 GT, as the 2009 model lost 6hp and 1 lb ft of torque.

Not that anyone will notice from behind the wheel.

Also, apparently the truck version of the L76 has VVT, but the car version does not. Does anyone know why they're not using VVT in the G8's L76?

 

Just a minor retune for the automatic version, which now has AFM standard. Meanwhile, the manual version continues with 270kW... which you don't get over there!

 

270kw is still 367hp.

Not a big difference between our 362 horse version.

 

Power didn't change. Both the 2008 and 2009 are rated at 361 HP (although sometimes you'll see 362 HP quoted).

As to why there's no VVT, I never found a definitive answer although I've heard it was due to packaging contraints.

 

There is no change or loss of power. The engine was recertified using regular fuel for 2009 in order to change the suggested fuel type to "regular unleaded" from "premium recommended" in 2008. (Remember near $5 a gallon premium fuel this summer?) If you do fill it with premium, you still get all 361 horses.

 

It's down to 355 for 2009. It was a very quiet change, but if you go to GM sales websites, or if you look on the GM Powertrain website, it's down to 355, which is only 265 KW. Is there a 265 KW 6.0 liter model in Oz now?



http://media.gm.com/us/powertrain/en...76_G8_GT_n.pdf

 

Thanks. That makes sense. So the engine is identical, but it's 355 with 87 octane and 361 with 91 octane, then?

 

Hmm, GM Canada's website still advertises 361 HP while recommending regular fuel (link). And reading the owner's manual for my 2009 G8 GT also confirms the use of regular fuel, saying "If the vehicle has a V8 engine, use regular unleaded gasoline with a posted octane rating of 87 or higher." Note that we only had 2009 models up here so this shouldn't just be a case of carrying stuff over from 2008.

 

You can tell that's old data, as it still has the 402 number for GXP horsepower. The '355' number only started showing up recently. I guess it was a case of GM dotting i's and crossing t's, and it explains the 87/91 confusion over the last year.

 

Pretty good article:

Holden division adds Active Fuel Management at the expense of horsepower

For the past decade, car manufacturers have steadily increased the power available in everyday sedans, trucks, and SUVs. It’s not uncommon to see full-size pickup trucks sporting large 5.7-liter V8 engines with over 380 HP and ordinary V6 family sedans are frowned upon if they don’t bring at least 260 HP to the table.

While the increase in power is no doubt helpful for those looking to race from stoplight to stoplight on the way from Target to Starbucks, increasing government regulations on fuel economy are forcing auto manufacturers to rethink their penchant for increasing the power of volume sellers at the expense of fuel economy.

General Motors’ Holden division in Australia is taking the opposite approach and is actually reducing the power output of its V8 engines in order to save a fuel MPG.

In Australia, the Holden Commodore -- known here in the U.S. as the Pontiac G8 -- uses a 6.0-liter V8 engine which produces 362 HP. However, the engine is being updated to include GM's Active Fuel Management (AFM) technology which allows the engine to run on four cylinders under light acceleration and while cruising on the highway. The APM feature drops maximum horsepower from 362 HP to 349 HP according to Autoblog Green.

The resultant combined fuel economy (city/highway) slightly rises from 16.44 MPG to 18.23 MPG.

Drive.com.au notes that Holden has stated on numerous occasions in the past that power increases of as little as 7 HP can make a difference in performance while driving. However, now that Holden is trying to tout its fuel efficiency benefits, it is singing a different tune.

"You've got 260kW of power there, you've got ample torque, I don't think anyone is going to complain about the fact that they've lost 10kW," said Ernie Tamburrini, Holden's Director of Powertrain Engineering. "If you didn't know the figures, I doubt you'd be able to tell that this car has 10kW less."

Holden Commodores with AFM functionality will be available in March.

http://www.dailytech.com/GMs+Holden+...ticle13851.htm

Looks like they're getting about 2 mpg combined with AFM, which I've done a 180 on. Too bad you can't get a G8 GT with a 6-speed