Just as most enthusiasts prefer manuals to autos, I wouldn't expect them to like CVTs either (or even as much as autos).

Even so, I think you are going to see a gradual acceptance of CVTs by the public at large just as we did with autos over manuals (very, very few cars today even offer manuals and fewer still are sold with manuals).

As to their fuel economy, I think the gains are modest but are there nevertheless...as with most MPG gains, evey tiny bit helps overall and most of the gains of the past 20 years have been a little bit at a time.

 

CVTs in snowmobiles and the like run belts. The friction a rubber belt provides is enough to keep things in check- but with over 60hp and wanting to see something last under constant strain on the road (reliability) you need to use a metal belt. The metal "chain link" CVT's arent efficient by any stretch of the imagination because of the tensioners and friction loads on them.

I was talking to John Bucknell (power train development for Daimler Chrysler) about them at an SAE conference, and even mentioning a CVT for a car made him wince. According to the work they've done on them, when you have less than 200hp, the drivetrain loss was about double that of a manual transmission variant - and with anything over 200hp, that loss just keeps going. He mentioned that the 300hp SRT4 was prototyped with one, and under high rpms was loosing nearly 30% of its output and pretty much tearing the transmission apart. When "factory modded" to nearly 400hp, when the turbo hit full spool it broke the belt or one of the pulleys every time.

He was convinced that good gear selection made a 6 speed auto better for anything other than an econobox - as some small, lightweight, low power cars do get better fuel economy with them. Also the Mini Cooper has a CVT with "preset gear ratios" which seems so rediculous to me... perhaps one of the actual auto engineers can chime in on why CVTs are being used.

 

FYI, 60hp is on the very low end for a modern snowmobile engine. 120+ is not unheard of nowadays (and to nitpick, transmissions are rated in terms of torque capacity not HP). Of course belts in snowmobiles are a maintenance item and usually get replaced every 1000 miles or so.

 

My friend has bombardia Outlander 800 HO ATV that has 75-80 HP and it has a CVT. It's made in Austaria. Very fast by the way... Top speed is like 91 MPH I think. Just insane for a ATV. We'll see how good it holds up.

http://www.can-am.brp.com/en-US/Vehicles/Outlander.800/

 

Like "R377" mentioned, an average (newer) snowmobile puts out well over 100 HP, but this is spinning ~8000 RPM or more (~10k for some of the Yamaha 4-stroke engines) but the clutches are only rated to approx. ~8500 RPM, then they'll start spitting belts off (so the high-revving Yamaha's are geared down). These machines are easily capable of speeds of ~100 MPH or more (high HP, ~150+ HP machines are capable of ~130's MPH!! ).

...but again, we're talking about something that weighs ~500 - 600 lbs, not a car/truck weighing ~3000 lbs MORE than that! And the TORQUE produced from snowmobile engines isn't nearly as high as a typical car/truck engine. And yes, the belts are part of "regular maintenance" ..... this wouldn't be cheap or easy in a car .

 

I picked 60hp because thats about the base-ish amount for the european and asian market mini cars, and some *might* actually survive for a thousand miles on a rubber-belt CVT, even with the weight of the car.

So what gets me is everything in the media thats put out onto webpages mentions how efficient and effective CVT's are. From everything that was discussed at the SAE conference, those great numbers only appear at lower load, lower rpm situations, and get terrible on the top end. I could understand their advantage for use in hybrids, as the computer gets more control of things for fuel economy, but otherwise?

And for grins, this is an image of the CVT belt Audi is using:

 

CVT can be made for high HP or high TQ engines, but I think a large concern is size in those cases.

The CVT's in Agco tractors and IVT in John Deere Tractors have proved hugely successful, and some of the John Deere's in testing are running numbers WAY above 300HP and HUGE torque. But as I was saying, it is hard to make small transmissions that can handle these sorts of abuse.

 

Nissan is using various CVTs in many applications now including some that put down some significant HP/Tq and some have been out there long enough that any special problems should have started to show up. But, as far as I know, they haven't experienced any abnormal warranty claims or special problems above traditional automatics.

Next time I'm at my dealer, I'll ask the service manager if they've noticed any increase in service on CVTs compared to standard autos.

 

OMG! That's a chain, not a belt?!?!