Originally Posted By: Garak
Originally Posted By: R2d2
However in my opinion (never claimed fact), direct injection has been dusted off in the US to meet EPA requirements and NO other reason.
I agree with both of you. There are a few cogent reasons to go with DI. An automaker could choose it for fuel economy, emissions, or even performance advantages. Simply put, though, in North America, we're stuck with automakers trying to find incremental gains in fuel economy and emissions savings, and having the average North American deathly afraid of diesels and the ridiculous political taint that is placed on hybrids.
And Shannow is dead right about fuel economy trends over the last several decades. Part of the problem, and that's another issue, is that there are so many vehicles that are grossly overweight. Additionally, we as consumers want power.
My G, a relatively small car, is only about 1000 pounds lighter than my F-150 Lightning was. Of course, it gets better fuel economy than the Lightning did, and has better performance. To put matters in more perspective, my G is only 200 to 300 pounds lighter than was my 1990 Town Car, which got comparable fuel economy. A two door sport coupe that weighs only 200 to 300 pounds less than North America's last land yacht? Yeesh.
So, tell me again, why did the 5.0 L Ford and the Panther platform disappear? So we could have much smaller vehicles that were just as heavy, had smaller engines with more power, and burned just as much fuel, on premium to boot?
But, as for direct injection, I think it's like a lot of technologies. All the bugs need to be worked out. I have faith they will be, but that doesn't mean I want to be a guinea pig, either.
I agree that the benefits of DI accrue in multiple ways simultaneously. DI allows for higher compression which gives higher thermodynamic efficiency, helping horsepower and fuel economy simultaneously. Take a look at the 2012+ Focus compared to the old Contour which occupied a similar place in Ford's lineup. The current Focus has the horsepower of a Contour V6 (after the 2007 SAE power revisions), and gets better fuel economy than the old Contour 4cyl. The Focus has 12:1 compression and runs happily on 87 Octane regular. Curiously the Focus weighs about the same as the old Contour.
The common wisdom is that modern cars are heavier than their forebears, and that this can be attributed to crash safety requirements, this is not the case, cars today are generally
bigger than their nameplate forebears. The additional deadening materials and luxury options we all desire also contribute to the problem.
Your G is heavy because it's a luxury car, not because it's new. It's slathered with copious amounts of heavy sound deadening material. That of course is a consequence of market forces, everybody want's a car that cruises at 75 mph at an interior noise level of 65 db, but the physics of sound propagation guarantee that's hard to achieve in a lightweight car. It's been this way for a long time. Compare the weight of a luxury car to the equivalent "regular" car from an interior size perspective, they're always a couple hundred pounds heavier at least. The spiritual predecessor to your G was no lightweight either, a 1992 300ZX Turbo weighed ~3,400lb. Bob Lutz was asked why GM's cars were always heavier than their competitors, consumer preference for quieter cars was his answer. I suspect the reason your G doesn't get any better MPG than your Town Car in the real world is that you actually use the substantially better performance available in the G.
My favorite old vs. new example is Honda products. Compare the interior volume of the 1992
Accord to the 2012
Civic, you'll find they're nearly identical in size. Curiously they're also identical in weight. In other words the Civic is no heavier than older cars of the same size, despite being much safer. The cars also have similar power, and yet the 2012 Civic gets markedly better fuel economy. Of course the 2012 Civic was panned for being noisy, and for 2013 they added sound deadening and weight. Now if you were to compare the 2012 Accord to the 1992 Accord you might think cars have gained lots of weight, but the 2012 Accord is HUGE compared to it's forebear.
