2011 Mitsubishi Outlander Sport: Mysteries of the CVT
November 15, 2011
Since there are fewer moving parts inside a constantly variable transmission than a manual transmission (or so Ive heard), I once asked an engineer to explain the CVT to me so Id know how it worked. He said it was dumb of me to think I could even begin to figure out the CVT, especially since I was so terrible at figuring out almost everything else about cars already.
First of all, he said, the whole idea of the thing goes against the laws of physics, since the key component is a chain (or belt) that you push instead of pull. If you start out by trying to push a length of string across a table instead of pulling it, he said, then the CVT must be living in an alternate universe.
Plus, he added, a Dutchman invented it.
So my education in the mysteries of the CVT didnt progress very far. But I have been driving cars with CVTs for a long time, and maybe thats worth a little something. They have been mostly Subarus, since the Japanese company popularized (if thats the right word) the CVT concept in the U.S. with the Justy and also brought in some wacky 600cc right-hand-drive hot rods with CVTs from the Japanese home market for journalists to drive (the Rex!). A financial connection with Subaru also brought the CVT to Nissan.
Now of course you stumble across CVTs at lots of different companies and here it is in the Mitsubishi Outlander Sport, just like it is in lots of things with 2.0-liter engines. (Apparently the more horsepower you have, the harder it gets to push the string across the table.) My only useful impression of this trend is that every CVT application seems to turn out different.
Here in the Outlander Sport, Ive grown to appreciate the CVTs performance in low-speed traffic. Aside from the usual drone as the transmission and engine try to get together on a mechanical speed that will balance optimum efficiency with optimum forward progress, I appreciate the stepless ratio effect as speed builds, especially compared to the clumsy ratio cycling that you get from some six-speed automatics (this means you, Audi/Volkswagen and BMW).
The trouble is, the CVT effect becomes less satisfying the faster you go in the Outlander Sport, as the optimum engine rpm always seems a little past the engines torque peak, which is the rpm almost every driver naturally selects while cruising through traffic. As a result, the Outlander Sport always feels like its driving through very deep and slippery mud when you get aggressive with the accelerator between 40 mph and 60 mph. No matter how fast you might be accelerating, the powertrain gives you no confidence.
I dont know why this is. Maybe the Outlander Sport weighs too much. Maybe there is not enough power from the engine. Maybe it is the electronic controls. Maybe its just the noise that is the problem, not the performance. All I really know is that the drivability of CVTs in some other small sedans and utility vehicles from other manufacturers (notably Nissan) is more satisfying.
For now, I continue to think the Mitsubishi Outlander Sport is spectacularly good as an around-town utility vehicle, far more successful than any of us suspected when it arrived in our fleet. Its also a nice vehicle when youre cruising to your destination, even one hundreds of miles away. But those moments when you have to lay into the gas pedal arent very much fun and keep you from embracing this vehicles overall goodness.
Wish that Dutchman were still around so he could explain it all to me.
Michael Jordan, Executive Editor, Edmunds.com @ 18,322 miles