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Discussion Starter · #1 ·
Just wondering, If the CVT doesn't "shift" gears, what is happening when you downshift to "S" or "L" ??? It feels like you drop into a lower gear ?
 

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ShaginWagon-

The CVT doesn't "shift gears" in the normal sense. What is does do is shift pulley ratios.

There are basically three main components in the CVT - two variable-diameter pulleys connected by a steel belt.

When you move the gear selector from D to Ds, a stepper motor in the CVT will decrease the effective diameter of the primary (input) pulley and increase the diameter of the secondary (output) pulley.

It's kind of like changing the gears on a ten-speed bike. By selecting different "gears" you are changing the diameters of the front and rear gear sprockets, and effectively changing the ratio. Instead of pulling on the chain the MO pushes on a segmented steel belt.

Does that make sense to you?

-njjoe
 

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To add to the excellent replies, to simplify it down even more, the CVT can set the positions of the cones such that it creates a discrete ratio much like a step automatic transmission - I read somewhere that there are something like 700 discrete ratios the CVT can set, and it "shifts through" these ratios in a "continuous" manner while you are driving.

Ds and L just tells the CVT computer to use lower ratios to keep the RPMs up.
 

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SHIFT_FASTER
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It's only 211 ratios, but it's pretty impossible to notice step changes :)

Also, you can "downshift" at any speed, and the computer will select the correct ratio, and you'll never bump the rev limiter :)
 

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Tyler_Canada said:
It's only 211 ratios, but it's pretty impossible to notice step changes :)
211 ratios? I wonder how Nissan came up with that number.

I have always been intrigued by the CVT, ever since owning a mini-bike with a belt-driven CVT as a kid.

I would loved to have seen Nissan incorporate a readout of the CVT ratio in a some sort of gauge or even a graphic on the display. It would be interesting to graphically see how the CVT reacts to changing conditions.

-njjoe
 

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njjoe said:
I would loved to have seen Nissan incorporate a readout of the CVT ratio in a some sort of gauge or even a graphic on the display. It would be interesting to graphically see how the CVT reacts to changing conditions.
Yeah, that would be pretty sweet.

On the old Skylines, there was a display of the torque split between the front and rear wheels.
 

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Tyler_Canada said:


Yeah, that would be pretty sweet.

On the old Skylines, there was a display of the torque split between the front and rear wheels.

It would be neat but in this era of "multitasking" in the car with people eating, drinking, yapping on the cell phone, the last thing we need is another moving display to distract drivers.
 

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Eric-

You can always ignore it (as I am sure most people would), but I would find it very interesting to see how the CVT adjusts to different conditions, especially in city driving. Or in Gonzo's case it would be interesting to see what "gear" the MO is in during high-speed runs.

I like gauges and meters. I like to understand the "inner-workings" of machines and mechanisms. Some people are content to know they turn a key and the car runs. I like to know why and how it runs.

-njjoe
 

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njjoe said:
Eric-

You can always ignore it (as I am sure most people would), but I would find it very interesting to see how the CVT adjusts to different conditions, especially in city driving. Or in Gonzo's case it would be interesting to see what "gear" the MO is in during high-speed runs.

I like gauges and meters. I like to understand the "inner-workings" of machines and mechanisms. Some people are content to know they turn a key and the car runs. I like to know why and how it runs.

-njjoe
I'm sure you can get the effect by driving around with a Consult-II hooked up to the diagnostic port.
 

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Eric L. said:


I'm sure you can get the effect by driving around with a Consult-II hooked up to the diagnostic port.
Eric-

Seriously, do you think that data is available through the Consult-II or one of the tools available to the public? I would love to see one of our inventive members develop a readout of some sort. Do you think it is feasible?

-njjoe
 

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njjoe said:

Eric-

Seriously, do you think that data is available through the Consult-II or one of the tools available to the public? I would love to see one of our inventive members develop a readout of some sort. Do you think it is feasible?

-njjoe
I'm sure that Consult-II can take the voltage from some sensor in the CVT (I'll make one up here, the "pulley position sensor") and output a ratio.

jaak found a way to manually shift through all the preset ratios (all 211 i guess) - search for that thread.
 

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Actually Jaak found a way to add the "5 speed manual shift" to Muranos that didn't already have it.

A Consult-II can definately read the CVT ratio, despite not being available to the public.

A publicly available OBD-II reader might be able to read the CVT ratio, but it would definately require custom code, as none out there yet have this ability.
 
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