What do you think of CVT transmissions?
Discussion
What is your experience with these? The Japanese manufacturers seem to have adopted them (Toyota, Honda, Nissan, Subaru) because I'm guessing they are more efficient but others are sticking to dual clutch or torque converter systems. Is CVT going to be the future or do they detract from the driving experience?
My wife has a CVT transmission in her new Toyota. I preferred it to the one in the Honda (Civic) but on balance still prefer the 4-speed torque converter auto in my car. The Toyota CVT is a strange one though. Sometimes it feels like a CVT i.e. the engine revs up and as a result I find it quite noisy and other times it steps like a "normal" auto. When you use the paddles (not very often to be honest) it drives like a Tiptronic with 7 pre-set ratios. I'm not really sure if I like it though really, although it is very responsive. My car with the torque converter can be sluggish to respond to the right foot, which means that the Toyota can accelerate as quick/a bit quicker despite having 60 less bhp and probably being a bit heavier. To be fair, my car is 10 years old now, so probably not fair to criticise but I think I would still favour a good torque converter auto over a CVT or probably a twin clutch box in something more sporting.
My wife has a CVT transmission in her new Toyota. I preferred it to the one in the Honda (Civic) but on balance still prefer the 4-speed torque converter auto in my car. The Toyota CVT is a strange one though. Sometimes it feels like a CVT i.e. the engine revs up and as a result I find it quite noisy and other times it steps like a "normal" auto. When you use the paddles (not very often to be honest) it drives like a Tiptronic with 7 pre-set ratios. I'm not really sure if I like it though really, although it is very responsive. My car with the torque converter can be sluggish to respond to the right foot, which means that the Toyota can accelerate as quick/a bit quicker despite having 60 less bhp and probably being a bit heavier. To be fair, my car is 10 years old now, so probably not fair to criticise but I think I would still favour a good torque converter auto over a CVT or probably a twin clutch box in something more sporting.
In theory they should be great, like constant speed propellers. In practise they seem a bit pants though.
Constant speed propellers have an additional control which let you decide whether you're aiming for power or economy. A car CVT has to second guess the driver and I think that's where it falls down.
Constant speed propellers have an additional control which let you decide whether you're aiming for power or economy. A car CVT has to second guess the driver and I think that's where it falls down.
They're ok for economy, rubbish for everything else, much like most things about modern cars.
The ones I've driven are a Prius (CVT without "stepped" gear simulation) and a Juke 2.0L petrol, turbocharged 4WD variant with the stepped CVT controlled by a + and - gear lever thing. Neither were up to much tbh. The Prius just makes a single pitch as it operates, but gets more groaning and harsh as the engine load increases. The Juke had a very artificial feel to the steps in the gears.
The ones I've driven are a Prius (CVT without "stepped" gear simulation) and a Juke 2.0L petrol, turbocharged 4WD variant with the stepped CVT controlled by a + and - gear lever thing. Neither were up to much tbh. The Prius just makes a single pitch as it operates, but gets more groaning and harsh as the engine load increases. The Juke had a very artificial feel to the steps in the gears.
I spent 3 weeks and about 4.5K miles driving around Utah, Nevada, Wyoming and Montana in a Nissan Murano in 2007. By the end of the trip, I quite liked the CVT in that. 245 bhp seemed to propel it along quite reasonably and it averaged 24 mpg US, so nearly 29 mpg Imp. That included quite a lot of cruising along Montana's two lane blacktop at 85 mph on the scarily accurate speedo. From memory, the only other CVT machine that I've been in was an old DAF 33 back in the 70's and ISTR that was remarkably nippy for what it was and at that time.
Claudia Skies said:
Nissan have got it pretty well sorted.
Who looks more stupid, the guy with a £150k Lambo and a "sports zorst" or the guy in a Nissan mushbox doing the same speed at 45 mpg?
Erm.....Who looks more stupid, the guy with a £150k Lambo and a "sports zorst" or the guy in a Nissan mushbox doing the same speed at 45 mpg?
Im in the USA these days and have driven a few Nissans (nothing special) with CVT 'transmission', not really an auto driver so hard to compare for me but what I do like is how you can't feel it changing gears especially when coasting down hill.
Oh and I hear it has KERS, so I can practice my f1.
Edited by dench on Friday 5th December 21:41
Claudia Skies said:
Nissan have got it pretty well sorted.
Who looks more stupid, the guy with a £150k Lambo and a "sports zorst" or the guy in a Nissan mushbox doing the same speed at 45 mpg?
Erm.....Who looks more stupid, the guy with a £150k Lambo and a "sports zorst" or the guy in a Nissan mushbox doing the same speed at 45 mpg?
Im in the USA these days and have driven a few Nissans (nothing special) with CVT 'transmission', not really an auto driver so hard to compare for me but what I do like is how you can't feel it changing gears especially when coasting down hill.
Oh and I hear it has KERS, so I can practice my f1.
Edited by dench on Friday 5th December 21:42
Claudia Skies said:
Nissan have got it pretty well sorted.
Who looks more stupid, the guy with a £150k Lambo and a "sports zorst" or the guy in a Nissan mushbox doing the same speed at 45 mpg?
Erm.....Who looks more stupid, the guy with a £150k Lambo and a "sports zorst" or the guy in a Nissan mushbox doing the same speed at 45 mpg?
Im in the USA these days and have driven a few Nissans (nothing special) with CVT 'transmission', not really an auto driver so hard to compare for me but what I do like is how you can't feel it changing gears especially when coasting down hill.
Oh and I hear it has KERS, so I can practice my f1.
Edited by dench on Friday 5th December 21:42
I generally prefer autos to manuals.
Have driven a few CVTs (including the '70s DAFs) and been in more as a passenger.
I think the main intended advantage of CVTs is that the engine can stay at its most efficient operating speed for the speed/load/acceleration needed at the time, but strangely that is the very thing most drivers don't like.
And - er - once again, the Prius doesn't have a ratio-changing gearbox, be it CVT or anything else. It's more of an epicyclic differential.
Have driven a few CVTs (including the '70s DAFs) and been in more as a passenger.
I think the main intended advantage of CVTs is that the engine can stay at its most efficient operating speed for the speed/load/acceleration needed at the time, but strangely that is the very thing most drivers don't like.
And - er - once again, the Prius doesn't have a ratio-changing gearbox, be it CVT or anything else. It's more of an epicyclic differential.
Had one on an Estima Hybrid in Japan and it was pretty suited to the car. Remember it being a bit slow and thrashy getting up to speed, but that's probably more down to the sensation created by the rev holding CVT, the slightly underpowered petrol part of the equation and the utterly massive body jammed to the brim with toys it was lugging.
Nothing specifically wrong with it but it was utility motoring at it's finest. Not a fun drive, but that wasn't really what the car was about (it was a fine ownership proposition and the most practical car we've owned by some distance).
CVT, though not a patch on a modern ZF for auto driving seamlessness, was not really notably different than a torque convertor or dual clutch automated manual in stop start traffic.
It wouldn't work in a performance car for me where the feel of changing gears is part of the fun but was otherwise OK.
Nothing specifically wrong with it but it was utility motoring at it's finest. Not a fun drive, but that wasn't really what the car was about (it was a fine ownership proposition and the most practical car we've owned by some distance).
CVT, though not a patch on a modern ZF for auto driving seamlessness, was not really notably different than a torque convertor or dual clutch automated manual in stop start traffic.
It wouldn't work in a performance car for me where the feel of changing gears is part of the fun but was otherwise OK.
The major problems with CVTs - other than the sound, which is a matter of mechanical refinement and user perception - is their inefficiency compared with a manual gearbox as all currently-available CVTs work by either friction or hydraulic means. The extra losses in the transmission counteract the efficiency gained by keeping the engine at its optimum operating point for the required power.
Incidentally: the Toyota Hybrid setup (as used in the Prius, CT200h, etc) isn't actually a CVT at all. It's a fixed-ratio gearbox that uses a single epicyclic gearset driven by two independent sources (one being an electric motor-generator, the other a petrol engine with a second motor-generator directly connected to its crankshaft) which approximates the operation of a CVT, but with much greater efficiency as there are no frictional losses.
(ETA: I believe that the bigger Toyota and Lexus hybrids such as LS600h and RX450h use a conventional CVT in conjunction with the electric motors and such.)
Incidentally: the Toyota Hybrid setup (as used in the Prius, CT200h, etc) isn't actually a CVT at all. It's a fixed-ratio gearbox that uses a single epicyclic gearset driven by two independent sources (one being an electric motor-generator, the other a petrol engine with a second motor-generator directly connected to its crankshaft) which approximates the operation of a CVT, but with much greater efficiency as there are no frictional losses.
(ETA: I believe that the bigger Toyota and Lexus hybrids such as LS600h and RX450h use a conventional CVT in conjunction with the electric motors and such.)
Edited by Jonny_ on Friday 5th December 22:26
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