My whole life, we have been taught that large, slow turning engines producing low-end torque more more efficient than smaller high-revving ones. There is no doubt in my mind this is still true. Yet, lately, the trend is towards smaller engines even with turbos. When efficiency is the name of the game, why is this being done?
Let's say we need 250bhp to get the job done. It has always been more efficient to have a 4.0l engine make this at 5,000rpm than a 3.0 at 7,000rpm in terms of fuel economy. But, look what's going on in the industry. Ford and all the others are making these tiny engines with big turbos running high rpm's!
The answer is the government! Whenever something doesn't make sense, the cause is the government. The epa has been changing it's testing procedures in a way that favors small screaming engines. These engines get better mileage in their tests because the tests are gamed by the manufacturers. They set the parameters of the engines so that they can get through the test with using as little boost and rpm's as possible. This gives them a small, unboosted, low rpm engine as the test sees is. They then market the car to you and me with the performance figures based on the high rpm, 10 psi or more boosted results.
The problem is, you aren't going to get anywhere near the mileage the epa claims when you have that thing wound up and boosted like you will in the real world. The driveability sucks too because you have to spin the thing above 4,000rpm just to get it down the street, all the while getting half the mileage you were promised.
I noticed this with my Mustang 3.7 V6. It had 305bhp and was a rocket if you kept it wound up. But, the mileage was crap. If I kept it below 3,000, the mileage was great, but it was slower than a 1980's Rabbit Diesel. Now, they are pushing the 3.7 aside for a 2.3 turbo! They say it makes the same power and gets better mileage. It won't get either under normal conditions. You have to drive the thing like it has two engines to get one or the other. Foot to the floor and shifting at 7,000+rpm for any kind of performance, or lug and loaf around for any kind of mileage.
In 10 years, the epa will change it's testing again and we will see the big, slow turning engines coming.
Ecoboost my ass. You can eco, or boost, not both. The Taco will likely come with turbo at some point. The problem is it will be a 2.0l and we will be told it will be "better".
and I knew the mpg' going in to this deal. I just don't understand why they can't sqeek out a few more miles out of a gallon. Don't get me wrong, I'm lovin my new little truck, and am getting better mileage than my other trucks, (like 7mpg) but this little one is the smallest I have ever had (in size), and I have never owned a "car", just Jeeps, Bronco's and "full size" p/u's, all with hungry V-8's.