CVT transmissions Love them or Leave them
DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ Pics |
2013-05-10 186905
CVT transmissions have been lauded for higher fuel efficiency and 6 speed transmissions. On the negative side they are criticized for boring performance.
When I drove my brother's 2012 Hyundai Elantra it was really really dull, just like driving the old 2 speed autos from ancient times.
Last year the auto pundits chastised the Subaru Forester because it used a conventional 4 speed automatic rather than a contemporary 6 speed auto. Now that the forester has a brand spanking new CVT 6 speed, the experts say it is dull, and that they do not recommend buying it, you should only lease it :)
So whatever you have it is the opposite that would be more appealing? It is tough writing car reviews after all!
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CVT transmissions Love them or Leave them
hardwood
Join Date: Dec 2002 Posts: 3583 iowa |
2013-05-10 186913
Dennis;
I'm not up to speed, (no pun intended), with CVT's in autos, but am somewhat familliar with them in farm tractors.
A true CVT has no set ratios like four speeds, six speeds, etc, the CV stands for constantly variable just like a hydrostat only it has a true mechanical connection instead of a fluid connection like a hydro. The Fendt Co. has had a CVT for years and others, including Deere that I'm familliar with have jumped on the band wagon. A few years ago I drove a 7000 series Deere with a CVT under load at a field demo. There were all sorts of situations you could set it to automaticly compensate for like max pull, max fuel economy, and I'm sure others that I don't remember now. OK, now I had the same feeling as you did with your brother's car, it was a dull thing to drive, there just wasn't much for the driver to do only steer, and now of course the GPS has taken over most of the steering in the latest tractors. My brother in law drove a GPS Deere for a neighbor doing fall tillage, I don't know if it was CVT, but he said the GPS made it a really boring thing to drive.
They ramble on and on about the effeciency of the six speed automatics, etc., I'd love to have a six speed manual in something just for the "fun" of driving it.
Frank. ....
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CVT transmissions Love them or Leave them
kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon Pics |
2013-05-10 186914
Some misc. rambling follows :)
People who drive automatics are used to a kick down when they punch the accelerator. If the downshift is missing they think the car is sluggish and boring. When CVTs market "speeds" the speeds are programmed set points of the CVT but they still don't feel like the old autos.
I think the new fancy automatics, the ones that deliver mileage equivalent to manual transmissions, are more like manual transmissions than the autos of old. They often advertise single or dual clutch automatics. The difference is that they clutch and shift action is automated so they don't suffer the inefficiencies of old style automatics. Some of the really good ones can shift gears in 10ms or so.
Supposedly Ford and GM are collaborating on development of a new 10-speed automatic. I hope it turns out better than the GM transmissions of the last 30 years.
Anyway, if you have enough speeds then the differences with CVTs blurs. ....
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CVT transmissions Love them or Leave them
greg_g
Join Date: Jan 2004 Posts: 1816 Western Kentucky Pics |
2013-05-11 186921
My 3720 has what John Deere calls eHydro, but to me it's a CVT. Set the throttle, push the pedal. The positive engagement offered by the five geared tractors that preceded it made ME feel in charge. This JD deadens that feeling, almost like IT wants to be in charge.
My two kids drive Nissan CVT, a Murano and a Pathfinder. Compared to the 8-speed autos in my present and previous SUVs, riding in the CVTs is unimpressive. The 8-speed is a Aisin/Borg-Warner collaboration that I unofficially call a "manu-matic". I can move the shift lever out of full auto, and go up and down all 8 gears with a flick of the wrist. Sorta like an 8 speed manual with no clutch pedal where one eyeball on the tach makes the decision of when to shift. The present car has an upgraded version of that basic transmission with the addition of both a Sport mode and an Off-Road mode. Plus I have small "paddles" on the steering wheel to use when in "manu-matic" mode. Better than a boatload of CVTs any day !!
//greg// ....
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CVT transmissions Love them or Leave them
DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ Pics |
2013-05-11 186928
Thanks Greg, I was under the wrong impression that all 6 plus speed transmissions were CVT. ....
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CVT transmissions Love them or Leave them
greg_g
Join Date: Jan 2004 Posts: 1816 Western Kentucky Pics |
2013-05-12 186936
Well, it's advertised as an 8-speed. But if you want to get technical, it's actually a six speed with two overdrives.
Transmission ratios (x:1)
I = 4.97 (part of why I have no trouble towing 7700# from a dead stop. Uphill)
II = 2.84
III = 1.86
IV = 1.44
V = 1.21
VI = 1.00 (top speed reached with gasoline engines)
VII = 0.83 (top speed reached with diesel engines)
VIII = 0.69 (enhances fuel economy)
Final-drive ratio (x:1) 3.27
//greg// ....
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CVT transmissions Love them or Leave them
yooperpete
Join Date: Jan 2004 Posts: 1413 Northern Michigan Pics |
2013-05-13 186955
The CVT (constantly variable transmission) design is very effective for mileage but a real dog with regard to performance. The 6-speed automatic transmissions have been a great improvement over the older 4-speed designs. They are being replaced with 8, 9 & 10 speed designs. I drove an 8 speed in a Dodge Charger with Hemi last year which takes some getting accustomed to. (If you like a performance ride and a full sized car, you owe it to yourself to test drive one of these.) The shifter movement is different. This 8 speed is a German design that is also being used by BMW and a few others.
All of these take a little to get accustomed to, but do give better mileage while performance is decent almost like a manual transmission. The onboard computer has a slight hesitation. My 2012 Dodge Journey has a 6 speed automatic with 283 HP VVT V-6. If at 55 mph you pull out to pass and step on the accelerator nothing happens for a split second (it has to decide how far to shift down) then it kicks in and acceleration is good. As you pull in, you're doing about 80 mph. I found that if you step on it and then step on it more while it is thinking it seems to get confused and the hesitation is slightly longer yet before it kicks down a couple more gears before your head snaps back. Its rated 283 HP acts more like over 300 HP. ....
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