Just taking off from the 5 or 6 speed topic, how come all automatic transmissions don't go to a CVT? Wouldn't this be the most efficient method to use in any vehicle? Would it not also solve the problem of "one upping" each other with another gear which could be good or bad?

 

The problem so far is they can't make a CVT handle 300-400+ lb ft of torque.

 

what is the weight comparison between a CVT and conventional auto?

 

Plus, I don't know that they offer much of a fuel economy advantage over a more traditional automatic with 6 gears (let alone 7 or 8).

They fall short of manual tranny fuel economy, and I don't think they are much ahead of the good autos. Combine that with the torque capacity issues, as mentioned above, and ...

 

I have heard 10% better fuel economy over auto's, but was a year or two ago and probably compared against an a4. I would prefer an A6-8 over a cvt.

 

Torque capacity and durability are the main ones. Also, because of the 'rubber band effect', they feel very funny to people used to discrete gear ratios and it tends to turn consumers off. Another disadvantage is that you need some kind of clutching device to get going from a stop, but because CVTs are perceived as "automatics", no one wants to deal with a clutch. That leads to either a powdered metal clutch (like Subaru used) or a conventional torque converter, but then you lose some of the efficiency you were trying to gain.

 

I wouldnt want to own a car with a CVT . A auto is bad enuff , but the CVT expirience is definately odd ...ick .

 

Subaru and Honda have both used CVT transmissions with very little success. I know if a Honda unit fails, you throw it away and buy another from the dealer. No parts are available for them.
The theory/operation looks good "on paper". Let's see if Nissan can get them to work/last.

Frank
CPT

 

Many buyers do not like the CVT and how it feels compared to a conventional automatic.

 

GM dropped the CVT in the Vue because of customer concerns. It just seems like it needed a little more time to develop and iron out any shortfalls.

 

Actually, they dropped the CVT because it was the #1 warranty item in all of GM. Not propotionally to sales, but #1 period. I was on the team that launched the 4T45.

 

The system seems to work well in snowmobiles . But maybe that's where it should remain??

 

The Nissan Murano has CVT. If it gets better fuel economy with the CVT I'd hate to see what it gets without it. My friend has one and it gets about the same fuel economy as most Yukons I know.

 

That can't be! GM = teh big, evil dino-oil pusher who uses baby seal blood in its paint process and human remains in its interior materials, while the Japanese companies are green and friendly and will help your Grandma if she has fallen and can't get up!

No way they build a fancy-pants midsize crossover SUV that gets mileage on par with a hulking monstrosity like the Tahoe!!

 

Doesn't the Nissan CVT "simulate" a set of normal gear ratios, essentially eliminating any advantage it might have over a conventional automatic?