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Nissan's Xtronic CVT in the Altima 3.5 SR changed Michael Vaughan's opinion about CVTs. (MikeDitzPhoto/Nissan)
Nissan's Xtronic CVT in the Altima 3.5 SR changed Michael Vaughan's opinion about CVTs. (MikeDitzPhoto/Nissan)

The Green Highway

Go ahead, give me the gears Add to ...

Okay, I've changed my mind. I'm not saying I was wrong, because no journo ever does. Let's say new facts have come to light. I have reconsidered rather than retracted. I now like CVTs, at least one in particular, and will no longer denigrate them as a category.

A computer controls just about everything in a car today and the software for the computer that controls the CVT in the latest Nissans is very good. You can drive these cars and never be aware that it's a CVT and not an ordinary automatic, yet still get the fuels savings that this simple and now refined device provides. Nissan says a car equipped with a CVT gets eight to 10 per cent better fuel economy compared to the same car with a conventional four-speed automatic transmission.

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Oh, you've caught me. Not all cars these days have conventional four-speed automatic transmissions. Don't buy one if offered. There's a huge change taking place in transmissions. Suddenly there are as many tranny choices as engines. And CVT for most of them should be the right answer.

So what is it? A continuously variable transmission, or CVT, is a type of automatic transmission that provides better fuel economy, more useable power and a drive even smoother than a traditional automatic. Today, automatics usually have four gears but they also come with five, six, seven or eight. Sounds like a lot of hardware whirring around and it is.

Instead of a bunch of gears, CVTs use a pair of variable-diameter pulleys shaped like a pair of cones that have a metal belt or chain running between them. There's a pulley on the engine side and a pulley on the drive wheels side. Moving the chain up and down the pulleys varies the transmission's ratio just like a 10-speed bike moves the chain over larger or smaller gears to change the ratio.

The CVT's computer will change the engine speed to deliver maximum power for accelerating and maximum fuel efficiency for cruising. And the whole thing costs a lot less than all those gears going around in a box somewhere. In a CVT the computer has an infinite number of "gears" from which to choose.

When you get away from the problem of how early cars with CVTs sounded, with the engine racing as you stood on the gas, you discover that CVT provides faster acceleration than a conventional automatic or manual transmission while delivering superior fuel economy. The software programmers have now figured this one out. And if you're saving, let's say six or seven per cent of fuel burn to be on the safe side, why wouldn't you go CVT?

Yes, I remember that the Dodge Caliber, when it first came out, had a horrendous CVT. When you hit the gas, the engine went off like a weed whacker. But that was years ago. The best I've driven lately is Nissan's Xtronic CVT.

I recently did the Muskoka weekend trek in an Altima 3.5 SR. This is a very pretty little coupe, with enough trunk space for several envelopes, powered by a 270-horsepower, 3.5-litre V-6 engine. The knock against CVTs was that they would disintegrate under power, i.e. they were better for motor scooters. However the Altima has power to burn and the transmission was totally unremarkable - barely noticed. And that's what you want if you add something that saves six or seven per cent of fuel.

The other thing I could write about is twin-clutch transmissions, also known as the Direct Shift Gearbox (DSG), but fortunately for you I'm running out of space. These things deliver race-track performance with near-instantaneous gearshifts. They also increase fuel economy, but they are also extremely complex boxes that drive the cost up not down.

Yes, I think the CVT is here to stay and I give Nissan the credit for producing the first one that I would be happy to live with. The rest are coming on fast.

So when faced with a bewildering number of gear ratio, single clutch, double clutch, torque converter options I think you will be soon safe to take the CVT.

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