Let the modding begin! (How US carmakers will meet the 35 mpg CAFE target)

[MetroMPG]

The Big 3 threatened (comments from Lutz in particular come to mind) that the only way forward to higher fuel economy would be through expensive technology (hinting at hybrids), and that consumers would pay the price.

But as we already know, there's still a lot of low-hanging fruit yet to be picked:

Industry experts said the first changes will be relatively subtle, relatively cheap and relatively soon. They'll include improved aerodynamics, six-speed automatic automatic transmissions and dual-clutch manual transmissions. Engine-driven components like power steering pumps will give way to electric ones. More efficient gearing and tires with lower rolling resistance will bring still more improvements. The cumulative effect can be significant. Ford says these tactics boosted the fuel efficiency of the V-6 Taurus by 10 percent.

Subcompacts are the fastest-growing segment of the market, but no one expects Detroit to dump SUVs in favor of microcars. Instead, automakers will use a lot more aluminum, magnesium and lightweight steel to reduce the weight of all their cars. Ford has said it will trim 250 to 750 pounds from every car in its lineup between 2012 and 2020.

The most radical changes will come under the hood. Automakers will embrace direct injection -- a more efficient means of getting fuel into the combustion chamber -- in a big way and bring more diesel and hybrid drivetrains to market.

Source: Wired - How Detroit Will Reach 35 mpg

[brucepick]

IHMO the biggest improvement would be to wean American drivers off vehicles that have twice the power needed.

My '89 Euro-beast weighs about 3070 lb and the engine is 115 hp. Any car currently on the US market has a much higher hp/weight ratio - '07 Camry 4-cyl is 158 hp/3263 lb. And the V6 is 268 hp!

True that before mods, I rarely would win the stop light derby in this car, but so what? It always gets me where I'm going.

I have to admit that turning all cars into total gutless powerless slugs would turn the public against the industry. It happened in the '70's; people couldn't wait for more powerful cars to be available again. But 268 hp for a 3300 lb car? People actually think they need that to do battle with freeway traffic or something. Let them learn other ways to get through life.

[brucepick]

OK, I vented my spleen there.

Makers definitely need to use all the low-hanging fruit that's available. I'm sure all the items mentioned in the quote have good potential.

One thing I've noticed is semi-bogus oem front fairings or air dams. Many of them are so full of holes and pockets of various types that they don't help smooth the air flow as much as they could. They could be better.

[DifferentPointofView]

^
But some larger vehicles like vans and stuff would get even more terrible mileage if they didn't have the power. Some trucks that have a v8 get better fuel economy than the v6 version cause they don't have to work as hard to do the same amount of work. True that we don't need all the power, but I think that if we had more torque vs. power we could do better. The AMC 4.0L I6 in my Jeep Makes 190 rated horsepower, but that is because the nice torquey drivetrain makes me never have to do much to get the car to move. They "upgraded" the 4.0L in 96', which got 185 rated horsepower, even less than before, but they got a good boost in torque, the force required to get something moving.

The 06' V Dubb GTi has the peak in torque at 1800 RPM, which is great for city driving and less throttle when accelerating. The less we have our foot on the gas pedal the better, and with more gears we could have a high final drive gear ratio, and a low 1st gear ratio. It'd be a good start at least.

[cfg83]

MetroMPG -

I never heard of "dual-clutch manual transmissions" before :

How Dual-clutch Transmissions Work
http://auto.howstuffworks.com/dual-c...ansmission.htm

Hands-On or Hands-Off
A dual-clutch transmission offers the function of two manual gearboxes in one. To understand what this means, it's helpful to review how a conventional manual gearbox works. When a driver wants to change from one gear to another in a standard stick-shift car, he first presses down the clutch pedal. This operates a single clutch, which disconnects the engine from the gearbox and interrupts power flow to the transmission. Then the driver uses the stick shift to select a new gear, a process that involves moving a toothed collar from one gear wheel to another gear wheel of a different size. Devices called synchronizers match the gears before they are engaged to prevent grinding. Once the new gear is engaged, the driver releases the clutch pedal, which re-connects the engine to the gearbox and transmits power to the wheels.

So, in a conventional manual transmission, there is not a continuous flow of power from the engine to the wheels. Instead, power delivery changes from on to off to on during gearshift, causing a phenomenon known as "shift shock" or "torque interrupt." For an unskilled driver, this can result in passengers being thrown forward and back again as gears are changed.

[diagram of dual-clutch transmission, 6-speed basic design]

A dual-clutch gearbox, by contrast, uses two clutches, but has no clutch pedal. Sophisticated electronics and hydraulics control the clutches, just as they do in a standard automatic transmission. In a DCT, however, the clutches operate independently. One clutch controls the odd gears (first, third, fifth and reverse), while the other controls the even gears (second, fourth and sixth). Using this arrangement, gears can be changed without interrupting the power flow from the engine to the transmission. Sequentially, it works like this: ...

EDIT: Hrmmmm, on second thought, I don't like this. I won't be able to coast in neutral anymore, .

CarloSW2

[brucepick]

OK, I didn't differentiate between hp vs. torque. Torque is more significant in just about every meaningful sense.

For trucks that need to be large and have large load capacities of course the needs are different.

But many large vehicles drive to work daily, carrying only a driver and a lunch or a few papers. I just don't buy the concept that these vehicles need to have a load capacity of one or two tons, and that the engines need to move that load as if the weight weren't there.

I'm still driving a beast I bought when gas was $1.60. I bought my first Volvo wagon when I had a business that required me to be able to lug stuff around and it served very well. Now with gas above $3 and climbing, my next car will be smaller and get better FE - but that's off in the future somewhere.

Meanwhile, I'm doing what I think most of us are doing - attempting to get the best possible FE from our current vehicles.

[MetroMPG]

Originally Posted by brucepick

IHMO the biggest improvement would be to wean American drivers off vehicles that have twice the power needed.

Unfortunately, "the weaning" is only going to happen (for the majority) when fuel costs as a fraction of the household budget become a pressing issue. We're not there yet in North America.

[MetroMPG]

Originally Posted by cfg83

MetroMPG -

I never heard of "dual-clutch manual transmissions" before

...

EDIT: Hrmmmm, on second thought, I don't like this. I won't be able to coast in neutral anymore, .

You know what? I think the writer got the terminology slightly wrong. They're really semi-automatic manuals, or automated manuals.

As for the neutral question - it's a good point. I know, for instance, that the Canadian market smart cars (single clutch automated manuals) can't do ICE-off coasting. (The problem isn't getting neutral, strictly speaking. It's that once there you can't restart the ice if you kill it - until you stop & go to park). Not sure what the situation will be with the next gen ('08) cars.

But I'm thinking you've got to be able to select neutral, even with the dual clutch units, otherwise you couldn't tow or push them.

[MetroMPG]

Originally Posted by DifferentPointofView

Some trucks that have a v8 get better fuel economy than the v6 version cause they don't have to work as hard to do the same amount of work.

That sure sounds like an urban myth to me! (But I'm willing to stand corrected if you can point me to EPA figures that show this.)

[Silveredwings]

Originally Posted by MetroMPG

The Big 3 threatened (comments from Lutz in particular come to mind) that the only way forward to higher fuel economy would be through expensive technology (hinting at hybrids), and that consumers would pay the price.

They have always used that fear tactic to avoid having sensible choices foisted upon them. Meanwhile look at the hole they've dug themselves into. BTW, who else do they suggest will pick up the bill if they have it their way?