CVT--Is it working the way it should?

[MadHungarian]

How does this thing work/is mine working correctly? In non-CRT automatics, when one lifts off the gas the car coasts, almost as if it is free-wheeling. In my Rogue it seems more like there is a slight brake drag, with the car seeming to slow more than with a non-CVT transmission. It this the way it should be, or does it explain my less-than-expected low gas milage--less than 20 mpg with very conservative driving (but in much stop-and-go traffic)? Do you experience the same deceleration sensation? Thanks.

[kerrton]

Hi there, basically I'd describe my CVT as performing and feeling the same way as a conventional auto other than not shifting. Can you provide more details, give us an example, does it do this at around-town speeds, highway or both, what do your rpms look like as you are declerating? I coast all the time in my Rogue just as I would in a conventional no problem.

If I had to guess I 'd say you've got brake clearance issues, that's probably the first thing to check

[Pescakl1]

No, that is the way it is supposed to work.
In fact, that is my only complaint about the CVT, they put the engine brake setting on a little bit too strong.
If that is really bother you, it can been changed by the dealer but unfortunetaly, there are only two settings available where it seems they planned for a third one initially.
The other setting is no engine brake at all, and the problem is that you will eat your brakes way too fast.
They seem to have planned a mild engine braking setting, but as Philip found out, it is not available for the Rogue.
Too bad for us, we will have to live with that.
My advice would be to keep your foot slightly on the throttle in order to decrease the engine braking, but it is quite hard to get it right all the time.

[kerrton]

I'm going to have to disagree with Pecakl1 on this one. The engine braking feature of the CVT only kicks in when you start a downhill decent. If you start rolling downhill and aren't pressing on the gas, the CVT will select a lower gear ratio to slow you down, but this DOES NOT happen on flat or gently sloping ground - unless you really hit a significant hill slope you won't experience this. And when it does kick in, you know it because your rpms climb quickly.

From what I gather from MadHungarian's post, he is saying that this happens to him all the time under all circumstances with this Rogue, including on relatively flat ground. I'm assuming that as he's coasting his rpms stay low, around 1200ish, is that right? If so, this indicates you're in a high gearing, but something else is causing you to slow down quickly such as stuck brake calipers causing your brake pads to continuously contact the rotors and slow you down. I don't know if this is the problem or not, but unless you're always driving downhill we can't blame this one on engine braking.

[Pescakl1]

Kerrton, do a test vs a automatic car.
My wife has a Honda Odyssey, and even if her car is quite intelligent at lowering gears when coasting to a stop (first time I see that on an automatic car), the engine braking is not as high as with the Rogue.
With traditional automatic car, we have quite the feeling that the car is sometimes even accelerating (false perception, it is just an impression), but it clearly is more free wheeling than a stick car, and, for me, than the CVT programming in the Rogue.

That doesn't mean that the rpms will go up, as it does when you are going downhill.
Remember that with a CVT you can have no direct relation between rpms and speed as contrary as a stick car for example.
I believe it is just that we don't have the same definition about engine braking (that is quite a subjective matter).
Same thing with engine noise, rattling, wind noise, what is too much, what is acceptable level?

[kerrton]

You could be right that the Rogue has slightly more CVT braking than a typical automatic, but in my experience the difference is quite minimal on relatively flat roads. I could be wrong but it sounds like MadHungarian is experiencing a significant "brake drag", but I'm not totally sure because he hasn't provided a lot of details.

You are absolutely right, these things are very much dependant on perceptions and opininos, so unless we get more specific information such as how abruptly MadHungarian's speed decreases when coasting, it's difficult to say.

[MadHungarian]

Thanks for the comments. I'll do a test drive and try to provide more details in light of the discussion, above.

[MadHungarian]

Test Drive Results

I have not yet been out on the interstates, so here are city-driving numbers (using the human counter: one-hundred, two-hundred, etc). Engine speed is 1000 rpm +/- while coasting. The Rogue is a FWD 2010 SL with 200 miles.

The most notable observation is that as I coast from 30 to 0 in “D” there is a definite and reliable change from engine braking (?) to free-wheeling (or close to it) at 20 mph. Same for you?

On a moderate downhill grade (15 degrees+/-), it takes approx. 10 sec to coast to 20 mph in “D” and 7 sec to do so in “N” (I need a longer hill to get to 30 mph)

On a slight downhill grade (2 degrees) it takes approx 12 sec to coast from 30 mph to 20 mph in “D” and approx 15 sec to do so in “N”

Going uphill on the same grade, it takes approx 8 sec to coast from 30 mph to 20 mph in “D” and approx 12 sec to do so in “N”

So, the major finding is that deceleration in “D” is greater than in “N”—which is not unexpected—and that engine braking appears to cease at 20 mph. I don’t know what to make of that, but I guess I will have to look elsewhere to explain my poor gas mileage (X = 16.6 mpg by the computer) with gentle stop-and-go driving. Suggestions?

[gpsmoucer]

Don't know what to say about your poor MPG. I'm getting 25.1 mpg (per computer) with average of ~33 mph (60/40 city highway).

Add me to the category that really likes the engine breaking feature. Maybe it's because my previous car was a late 90's Buick that was like a runaway roller coaster on hilly terrain. It actually gave you great mileage if you knew the terrain and just how much gas to give it to get to the top of each hill... but I ran through a lot of breaks on that car.

With the Rogue I find it does an awesome job of holding whatever speed I was going on all but the steepest grades (and when it gets too steep and speed increases I use the handy paddle shifters to throw it into "3" for a little more slowing power - I'm determined to get full use of the extended transmission warranty . It's nice seeing other cars I'm following using their breaks while I'm just comfortably coasting down the hill.

[casperfun]

I read the following online about the Versa and it seems to pertain to my Rogue too:

Nissan Versa CVT Coasting Ability

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Quoted from Mudd from Nissasnversa.org forums


Quote:
Made a chance discovery today, at least on my vehicle. Have the 2007 SL with CVT.
I've noticed that when going about 60mph or so and let off, the motor holds rpm and I can feel the drag as the speed decreases. At about 20, the drag stops and the vehicle feels as if it's free-wheeling. Good, that helps with the fuel economy. Was wondering whey Nissan didn't do a little better and let it free-wheel at a higher speed. Would sure be a fuel saver. Had a Buick Rivera that did this at any speed.

By chance at a speed of about 40mph I let off and again just tapped the gas pedal. Surprise the rpm dropped to 1100 and continued to coast at 40 as there was a slight drop in the road. I did this again (tap) at higher speeds but could not get the same result.

So it seems on my car at least, if one taps the pedal at 40mph or less after removing foot it will go into free-wheeling mode. Maybe my vehicle has a Fluke? Don't know but I like this way. I'm going to mention this to the shop man at my next visit.

Would like to hear from anyone else that notices that on their Versa.

sweet! so it acts like N when the user lifts his foot off the gas... this could be the car for me I like how if you apply light throttle it will be in a deadband wannabe mode.... sounds promising!!!

And from what I read about the CVT ride, its almost hybrid like, when coasting you can't hear the engine. There were a few edmund users posting 40 ish tanks and their engines haven't even broken in yet! So I think this car looks promising since its 5000 cheaper (including the hybrid tax refund) than a new hybrid car.

[Pescakl1]

The most notable observation is that as I coast from 30 to 0 in “D” there is a definite and reliable change from engine braking (?) to free-wheeling (or close to it) at 20 mph. Same for you?

It is when the torque converter discouples itself, same thing than with an automatic gear. Therefore, the feeling of acceleration I mention previously.

As for reapplying some gas throttle after lifting of to decrease the engine braking, I will have to test it with the scangauge to see if this is software related (CVT going into higher gearing to decrease engine braking), or if this is due to the fact you put back some fuel to be burnt in the engine (by lifting off from the gas pedal, no fuel is used and engine is used as an air comressor... until reaching about 20 mph where it torque converter is discoupled and fuel is put back to keep the engine running).

Nothing surprises me in all that reading, everything sounds logical.

[MadHungarian]

Thanks again for the input. With 210 miles I am now down to 2 bars and 30 miles to go to empty. I'll refill the tank, compute mileage (assuming the dealer really filled it up--it read full when delivered), and do it all over again before complaining to the dealer about the mileage. I expected better than this . . .

[kerrton]

Yeah in 50/50 highway/city driving I get 8.0L/100km (29 miles/US gallon), in strictly city driving with a conservative style you shouldn't get any less than 25, but also remember that the mileage should increase as the engine breaks in. I didn't notice a big difference but a lot of owners on this forum reported an improvement over time.

[Pescakl1]

I read the following online about the Versa and it seems to pertain to my Rogue too:

Nissan Versa CVT Coasting Ability

--------------------------------------------------------------------------------

Quoted from Mudd from Nissasnversa.org forums


Quote:
Made a chance discovery today, at least on my vehicle. Have the 2007 SL with CVT.
I've noticed that when going about 60mph or so and let off, the motor holds rpm and I can feel the drag as the speed decreases. At about 20, the drag stops and the vehicle feels as if it's free-wheeling. Good, that helps with the fuel economy. Was wondering whey Nissan didn't do a little better and let it free-wheel at a higher speed. Would sure be a fuel saver. Had a Buick Rivera that did this at any speed.

By chance at a speed of about 40mph I let off and again just tapped the gas pedal. Surprise the rpm dropped to 1100 and continued to coast at 40 as there was a slight drop in the road. I did this again (tap) at higher speeds but could not get the same result.

So it seems on my car at least, if one taps the pedal at 40mph or less after removing foot it will go into free-wheeling mode. Maybe my vehicle has a Fluke? Don't know but I like this way. I'm going to mention this to the shop man at my next visit.

Would like to hear from anyone else that notices that on their Versa.

sweet! so it acts like N when the user lifts his foot off the gas... this could be the car for me I like how if you apply light throttle it will be in a deadband wannabe mode.... sounds promising!!!

And from what I read about the CVT ride, its almost hybrid like, when coasting you can't hear the engine. There were a few edmund users posting 40 ish tanks and their engines haven't even broken in yet! So I think this car looks promising since its 5000 cheaper (including the hybrid tax refund) than a new hybrid car.

OK, I had the possibility to do some experimenting yesterday, but not a lot as my drive is only 5 kms to get my daughter at daycare and bring her safely at home.

At 3 occasions after the car was enough warm to allow cutoff fuel while coasting to a stop, I was able to get 0 LPH and 0 LHK on the scangauge (fuel cut off when lifting my foot of the gas).
Even with barely not applying gas again (a few mm on the gas pedal), the scangauge always showed some fuel going back in the engine. And I was always above 20 mph so the torque converter was fully engaged.

Conclusion: Sorry guys, no free wheeling possible on the Rogue (I believe this is the same for the Versa listed above, but he will only know if he has a scangauge plugged to his car).
If you lift your foot off the gas, you will get some engine braking (either you find it moderate or not is your opinion on the matter), and if you apply back some pressure on the gas pedal, you will get some fuel burning.

[MadHungarian]

An up-date and an apology: The up-date: I filled the tank this morning at 222 miles. It took 14.5 gals to the first click for an average of 15 mpg. The computer said 16.5 (but the tank might not have been full to start with).

Now for the apology: I immediately drove 10 miles on I-85 with the cruise control set at 60 mph; the computer reported between 30 and 32 mpg. I drove back without cruise at speeds between 55 and 75 mph; no noteworthy difference in mpg. So I guess all is ok, and that the disappointingly low mpg is a function of hilly terrain, lots of stop-and-go driving, and long waits at stop signs and traffic lights (I see the mpg decreasing as I sit there). My apology is for starting a thread without sufficient data. But it did produce some really interesting stuff. Thank you.

[kerrton]

No need to apologize, if you don't discuss things then you may miss an opportunity to learn something new or to understand if you actually have a problem or not. If through this discussion you've discovered that your Rogue is running properly, then this was definately not a waste of time! And we had a new interesting discussion regarding coasting, freewheeling, fuel efficiency and few others, very good topic!