XTronic CVT on an X-Trail

[Callistus]

I have a 2009-model X-Trail equipped with XTronic CVT and noticed what appears to be a "should-I-stay-or-should-I-go" behavior in the CVT system that makes it spend quite an extra fuel.

Starting from standstill (e.g. stopped at a traffic light), when I accelerate moderately, release the pedal and then accelerate moderately again (as occurs when one's driving behind a clumsy driver) within 4 seconds, the CVT keeps the RPM at 2000 for about another 4 seconds without changing the car speed, which is pretty low in the case.

My guess is that because of the accelerate/release/accelerate sequence the CVT changes implicitly to sport mode, then waits for more throttle, which doesn't happen, so after those 4 seconds it decides to move back to economy mode.

The problem is that it wastes quite a lot of fuel since this situation happens very often in the city. I have test-drived 2 other cars identical to mine an it also happened on both of them.

Is that a way to change/configure this? I'd rather have the CVT chosing the mode based on how deep I depress the accelerator pedal, not based on sequences that occur commonly during heavy traffic, which evidently doesn't match with sportive driving.

I've also observed that, when climbing up a reasonably steep ramp (e.g., from an underground garage) with the CVT at the D position, when I don't step on the pedal at least halfway, the engine will come very close to a stall, choke for a moment and then elevate the RPM to get more power to finish climbing the ramp.

I have a car from another brand, also equipped with CVT, and it desn't show any of these problems.

[SteveTheTech]

Welcome to Nico,

I really do not know how much assistance I can offer you the x-trail is not available in my country but the CVT is. Now if you have the awd model some delay may be understandable as the steel belt inside the needs to change its position of the opposing pulleys. I have only had a chance to drive a few Sentras and a Maxima equipped with a gearless transmission. Below is a link to an interesting article from the Nissan Global library. It is no justification for some of the issues but they do operate on completely different principals than conventional transmissions.

http://www.nissan-global.com/E...4.pdf

http://www.nissan-global.com/E...a.pdf

[Callistus]

Thanks Steve! I'll have a look a that, test and come back with my impressions ASAP.

Again, thanks.

[Callistus]

Hello Steve,

I've studied the first document (the second I had already read previously), the concept is very nice but the application need a little polishment.

In fact XTronic CVT is very sophisticated, but somewhere in the way Nissan tried to make it predict so many driving conditions that it ends up giving ground for some undesired side-effects to spring out. The 4-sec delay is somewhat annoying and actually expensive.

My other car's CVT system is so much more predictable than that of Nissan that it almost feels like a manual-transmission car. The difference is that I can choose whatever "gear" I want just by using my right foot.

Thanks for pointing out the documents.

[SteveTheTech]

The difference between Nissan and other models is the modern Nissans use Infinite gear ratios. Even with "Sport" mode they are only rough pulley positions that output a gear like range. I wish there was something I could tell yu unfortunetly I do not have access to any X-trail information after 2006. Check with your dealer to see if there is a software update I know at least in America there are a few software updates for some of the CVT equipped vehicles.

This is a prime example of Nissan overengineering stuff again. The concept is great for ideal efficency all the time but the down side is the amount of sensors used to alter the pulley logic can cause issues on some demanding surfaces.

[Callistus]

The difference between Nissan and other models is the modern Nissans use Infinite gear ratios.

Steve,

Any CVT system use infinite gear ratios. As I mentioned, my other car is CVT-equipped car (a Honda FIT EX, for that matter) and it is much more predictable/more economical (engine size/weight difference/CX factor already discounted) but I agree with your software update point. Unfortunately I have found none, and that's why I've come to this forum.

Again, thans for your will to help.

[Callistus]

...at the same time I don't do the same regarding Ford.

Ford has chosen to establish a "visual identity". Nissan has not.

Choosing a "visual identity path" restrains creativity and comes from the primitive where "the customer must pursue the brand's identity".

I belive that "the brand must pursue the customer's identity". This is *ALWAYS* true.

In the middle of all that, Nissan could offer an option of engine behavior. A few changes in the software, and the customer has the same choice as a computer user has.

I sincerely suggest that Nissan offer, within XTronic, a choice of using Honda's approach. I've found Honda's CVT behavior much more akin to my linking than that of Nissan.

Matter to think about.

Why the hell not?