How to drive your CVT instead of it driving you
It has taken about 6,000 miles on my 2012 Altima 3.5 SR for me to figure out how to operate the CVT transmission. Due to the general confusion and criticism of the CVT, I decided to share my experiences by writing down some driving techniques I have learned. Some of this I learned by reading what other people have written on various forums. Although I have a strong mechanical background, I have never taken apart a CVT, nor do I have any training from Nissan. I can only assume the way I use the Sport or Manual modes does not cause any long term damage to the transmission. Some of this won’t be new information, but hopefully, it will help guys new to CVTs.
The owners’ manual states three specific things about the CVT. Do not tow any distance with the wheels on the ground, and do not coast with the transmission in neutral. It also says if you overheat the trany fluid, the computer will go into a limp mode.
Idle in neutral
I always shift to neutral after stopped. In my opinion, this takes the stress off engine and trany parts and lets the fluid in both cool down a bit. Other people say don’t do it, but offer no explanation of why.
Lock up occurs at about 5 mph when in Drive or Sport mode. If you are very light on the throttle, and keep the tach at 1,000 rpm as the car accelerates, you will see a dip in the rpm when the TC locks up at about 5 mph. I found this out after stopping on a steep hill. By chance, I started to accelerate slowly. Then I felt the car do a big jerk which I assume was caused by the TC locking up, but then immediately unlocking, in attempt to slowly accelerate up the hill. In order to avoid excessive or harsh lock ups, I will drive in Manual mode in stop and go traffic like parking lots under 5 mph, and when starting from a stop up a steep hill.
In Manual mode, the TC lock up occurs differently. It does not lock up at 5 mph like in D or S modes. I think it locks up at higher speeds. I did find an article that mentions the TC has a soft lock up mechanism where the lock up can change depending on conditions.
Gas Peddle Control of CVT
Nissan says a minor vibration and rumble at about 1,200 rpm is normal and doesn’t hurt anything. However, it can get pretty bad and annoy some drivers. If it becomes bad or annoying to you, see if the Nissan dealer will update your CVT under warranty.
A lot of guys don’t like it when the CVT pulls the engine rpm down too low, causing the vibration and rumble at about 1,200 rpm which also bogs the engine down and the car won’t accelerate. This is frequently referred to as the “rubber band” effect of the CVT. I think they are describing the main feature of the CVT which is meant to improve gas mileage.
If you accelerate lightly from a stop, the engine rpm will go up initially, but as the car speeds up, the computer starts to increase the CVT gear ratio which pulls the engine rpm back down. I look at this as one feature of the CVT which I can choose to use or not. I will use it if I want to drive for best fuel economy, but I will not use it if I want to drive more aggressively.
Try this little experiment. From a stop on flat ground, use just enough throttle to keep the rpm at 1,000 while you accelerate. Then practice using a bit more gas to keep the rpm at 2,000 while you accelerate from a stop. (These rpm numbers work on my 3.5 engine; I don’t know what they would be on a 2.5 engine.)
In both cases, the car will accelerate without the 1200 rpm vibration and rumble. Accelerating at 1,000 rpm is very slow, slower than normal traffic. Accelerating at 2,000 rpm tends to be a bit faster than normal traffic, which frequently ends up with me getting too close to the car ahead of me. When starting from a stop, I avoid this by letting the car in front of me get a few car lengths ahead, and then I let off the brakes and start to accelerate. This extra space allows me to accelerate from a stop at 2,000 engine rpm to avoid the 1,200 rpm vibration, rumble and rubber band effect. Once my car has enough speed and momentum, I will let off the gas and let the CVT shift to a higher ratio which lowers engine rpm and improves fuel economy.
The key point here is I am using the gas peddle to control when the CVT pulls into a higher gear ratio and avoiding the 1,200 rpm vibration, rumble and rubber band effect, rather than letting it happen automatically.
Going up a hill is another good example of how I use the throttle to control the CVT. To maximize fuel economy while on the flat road before the hill, I will be coasting along with just enough throttle to keep the car moving with the CVT in a high ratio and low engine rpm. Before the car starts to slow as it starts to go up hill, I will push in more throttle to get the CVT to down shift to a lower ratio, get the rpms up and climb the hill. As I go over the top, I will let off the gas, let the CVT pull into a higher ratio, drop the engine rpms to maximize fuel economy, and then stay off the gas as I coast down hill. The idea is to push the throttle down and down shift the CVT before it bogs down the engine. If you wait too long before pushing in more throttle, the engine bogs, the car slows, and it takes longer for the CVT to downshift and accelerate up the hill. That is not so different that down shifting a normal automatic or manual trany,
3 More Hints
1. Stay on the throttle when you up shift the CVT. I think this keeps higher hydraulic pressure needed to control the pulleys. This is opposite older style automatic transmissions where you let off the throttle to cause an up shift.
2. Constantly adjust the gas pedal. Back in the good old days of carburetors, being steady on the throttle provided the best fuel economy. With the CVT, I have to constantly change the position of the gas peddle to get the CVT to do what I want. For example, if I want to keep the engine rpm’s at 2,000 while I accelerate from a stop as the car speeds up, I have to keep adding a bit more throttle as the car speeds up to keep the rpms at 2,000 and prevent the CVT from shifting to a higher ratio and bogging down the engine rpm too soon. If the revs go over 2000 rpms, I let off the gas pedal a bit.
3. Watch the mile per gallon bar graph to get an idea how to be soft on the gas peddle. My old car did not have the mpg bar graph, but did have a normal automatic transmission. Without realizing it, I had developed a habit of just mashing on the gas to go as fast as I wanted. However, by watching the mpg bar graph, I was able to see how sensitive the throttle was to small movements. This helped me learn to constantly adjust the throttle to control the CVT.
4. The operation of the CVT will change at different throttle positions.
Here’s one example. Put the tranny in Sport mode. Sport mode tells the computer to insert artificial shift points in the rpm curve to mimic normal automatic transmissions. However, if you are light on the throttle, the shift points will be low in the rpm curve, or you may not feel them at all. If you are heavy on the throttle, the shift points will be higher in the rpm curve.
The Fun Stuff with Different Shift Modes
I rarely use Drive mode. In my opinion, it is there just to provide the best fuel economy. In this mode, the CVT is always trying to pull the engine rpm down. There are no actual shift points like a normal automatic transmission.
There are two exceptions. If you are cruising in Drive mode and want to accelerate quickly, you can hit the gas and push the shift lever left, into Sport mode. This forces the CVT to do a quick down shift, get the engine rpms up, and is very effective as a passing gear.
The gas peddle has a mechanical detent and click built into it about ¾ of the way to full throttle. With the engine off, push the throttle past ¾, you can feel the click. If you are cruising in Drive mode, assume 6th gear and low engine rpm, and do not push the throttle past the ¾ click, the CVT will stay in 6th gear and accelerate slowly. However, if you push the gas peddle past the ¾ click, the CVT will downsift, increase engine rpms, and accelerate much more quickly.
I normally drive in Sport mode which is where the CVT computer inserts artificial shift points. The harder I push the throttle, the higher in the rpm curve the shift points are. I cannot feel the shift points at all if I am very light on the throttle. When I feel like driving heavy on the throttle, this mode feels like a close ratio transmission. The other advantage of Sport mode, is I can downshift whenever needed to get the rpms up and prevent the CVT from lugging the engine down too much. The disadvantage is that gas mileage drops dramatically if I am really hard on the throttle.
I did the following tests under full throttle acceleration from a slow speed, such as entering a freeway.
In Drive mode, the engine rpm would stay at red line and did not pull down the rpm. I left off the gas at 80 mph, so maybe you have to go faster than that before the CVT starts to pull into a higher ratio to reduce engine rpm.
In Sport mode at full throttle, the artificial shift points were very close to the red line. When shifting, the rpms would drop a bit just like a normal transmission, but just enough to allow the engine torque to continue pulling hard.
In Manual mode, the rpms would go to red line. However, like a normal transmission, you should shift up a gear before the engine rpms hit the red line. If you didn’t, the car would not accelerate any further. If you actually hit the red line in manual mode, the CVT would up shift automatically. If you let off the gas after that, you will find the gear indicator on the dash in a lower gear.
When in Manual mode, and staying under the red line, the CVT holds a constant ratio, so the rpms will correspond directly with the throttle position. To me, Manual mode is just like a manual transmission without a foot clutch. I can go anywhere in the rpm curve I want, at any speed, in any CVT gear ratio I select.
One other aspect of Manual mode is that the CVT will automatically down shift as you slow down and let off the gas. If you are in Manual mode in 6th gear and slow to a stop, the CVT will automatically shift down to first.
I know this all sounds complicated the first time you read it. If you practice a bit to understand how to make the CVT do what you want, it will become second nature over time. The CVT does give you the choice of driving for economy or pushing it as hard as you want.
Feel free to add any comments or correct any oversights I have made.
Last edited by XLXR; 01-08-2012 at 03:04 AM.