• Jun 20, 2006
General Motors Vice Chairman Bob Lutz was bitten by the blogging bug again yesterday and uploaded a post to the company's FastLane Blog. Despite his hectic schedule the Chairman got some seat time in a pair of new GM products and wanted the rest of us to know he was impressed.

The two cars in question are the new Saturn Aura and Chevy Impala with the 3.9L Active Fuel Management system. While his impressions of the Aura sound like typical corporate fawning, especially considering few journalists have spent any time behind the wheel of one, Bob's take on the Impala's new powerplant sheds light on what AFM will do for the car's six-cylinder engine.

Like its use in other applications such as the General's V8-powered full-size SUVs, Active Fuel Management will switch off half of the Impala's six-cylinders in certain conditions, which do not include hard acceleration nor idling. Though some larger engines that employ cylinder deactivation can operate with half a motor while idling, that function was nixed for the 3.9L because a trio of pistons pumping makes for a rather rough idle. We'd guess AFM will be most active while crusing at around-town and reasonable highway speeds.

Lutz also points at that the Impala's fuel economy label likely won't change because of the addition of AFM, as the EPA's testing procedure doesn't take into account many situations in which the technology would make the most difference. Because of this, buyers will likely be surprised that their Impala beats the sticker's EPA rating in normal driving situations. In fact, the Impala Bob drove had an average of 29.8 mpg on its trip computer after several thousands of miles of operation.

[Source: GM FastLane Blog]


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  • 17 Comments
      • 8 Years Ago
      Thanks, Phoenix, I was just going to point that out. If fact, I don't think DC even has a presence in the Chrysler Building.
      • 8 Years Ago
      Laserwizard, you are an idiot!!!!! Get a clue ricecake.
      • 8 Years Ago
      "riceballs pretenting to be Americans"

      First, learn how to speak English. Second, being American has nothing to do with having loyalties to a corporation, such as GM; its about having an allegiance to a Country.

      "GM was the 1st to have designed DOD engines as the caddie had it 20 years ago but did not have the electronics back then to make engines run smooth enough when 4 cylinders where shut down."

      True, but GM also didn't invest in the needed R&D 20 years ago to make DOD a viable option until now. In the meantime, Dodge and Honda have already used this technology on a few vehicles.
      • 8 Years Ago
      Which of these engines runs on half the cylinders at idle? As far as I know they all deactivate cylinders only when cruising. Even a V8 on four cylinders would idle roughly. Does the MB or BMW V12 have this feature?

      With many highway miles even the current Impala will break 30 mpg. Fuel economy means nothing without knowing driving conditions. My father-in-law has a 2004 with the old 3.4 that gets 30-35 on the road. Once on the way to Michigan he averaged 33 on my tank and 35 on the other.

      Then again, the 3.9 earned some nasty EPA numbers in the G6, so it needs all the help it can get.
      • 8 Years Ago
      I'll accept Lutz's assertion that the EPA cycle isn't always representative of Americans' driving habits, but how is AFM suited to these patterns in ways the EPA cycle doesn't reflect? Lutz's reference to "idle" doesn't make any sense.

      I'd be ecstatic if Lutz's claims were true and this car pulled off 30mpg combined. I do fear that the car Lutz drove may have been a ringer.
      • 8 Years Ago
      LOL, "my TSX only gets 27 mpg but my mom's Impala gets 30-35 mpg". Obviously the TSX's 2.4 is more efficient you idiot. Look at what your rpms are when your on the highway and then look at your damn Impalas. WOW! The TSX revs alot higher....bring down to the same rpm and see which one gets you better mileage. Dumbass
      • 8 Years Ago
      So is that beautiful Impala SS that keeps showing up on this blog just a photoshopped Civic?
      • 8 Years Ago
      AFM isnt all the way there but at least it shows that there is some spark left in detriot. I would like to see a car that goes the other way. AFM always on and only off in special circumstances.
      • 8 Years Ago
      What Bob wrote was, "When I picked up the car it had several thousand miles on it. And the average fuel economy on the trip computer was 29.8 mpg!" Which means someone could have taken the car to lunch when it had 3324 miles, reset the trip computer, driven 5 miles and gotten 29.8 mpg.
      • 8 Years Ago
      "Where as if an American car built ANYWHERE in the world the profits come back home. This is a not complicated to understand."

      So which is it...are we supposed to support the Big 3 because they employ thousands of workers in US plants? Or since that's not going to be the case for long, should we support them because they bring home 'profits' to American investors. Or since they do not make a profit should we support them because their Executives make enough money to feed most of the third world.

      I can call up my broker (if I had one) and purchase shares of Toyota and get dividends (because they make a profit), a good percentage of which would be from the sale of cars to US customers. If I were concerned about keeping US money in the US then that might be one way to do it. Its certainly more effective then investing in GM stock...
      • 8 Years Ago
      "Look at what your rpms are when your on the highway and then look at your damn Impalas. WOW! The TSX revs alot higher....bring down to the same rpm and see which one gets you better mileage."

      Uh, so you're saying that if he drives his TSX at 50mph he'll get better mileage than an Impala going 70mph? And you're calling HIM an idiot? Wow...
      • 8 Years Ago
      Just because Foriegn car companies make automobiles in the states does not mean the profits stay in the states. Where as if an American car built ANYWHERE in the world the profits come back home. This is a not complicated to understand.
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