Important: The following is a text only archive!
For full features; Go to Nissan C-V-Transmission
I'm still experimenting with the Nissan Continuous Variable Transmission;
I've driven it about 600 miles so far. I haven't come to a conclusion yet
whether I should just leave it in 'D' and let the automatic transmission do
its thing, or to put it into the manual mode and use the up/down shift
paddle.
For those not familiar, the Nissan CVT has a mode where the shifter lever
is moved over into a special 'manual' zone. When in this zone, tapping the
shifter in one direction shifts up, and in the other direction shifts down.
Since it's a continuous variable transmission and there are therefore no
distinct gears, the paddle moves the transmission belt into 6 preset
positions. When the car comes to a stop, the shifter automatically
downshifts to 1.
I find in 'D' that it tries to keep the RPM around 2000. That's fine most
of the time, but slowing into a turn it seems to drop below 2000 and labors
the engine trying to gently accelerate out of the turn. If I goose the
throttle it jumps into action, but that's not what I'm after ( gas costing
what it does these days! ). If I take manual control, I can downshift to 3
just before a turn and have lots of pep to accelerate out of the turn with
the RPM up around 2500-3000. The automatic mode is just fine from a stop
accelerating to driving speed; it's just the turns that are sluggish.
So far, I've been using the manual mode if I know I'll be in a situation
with lots of turns, then push it back to automatic when I get to the long
straight sections or to the highway. The only down-side with this is
sometimes I get distracted waiting at a light and forget that I need to
upshift until the engine starts getting a little noisy over 4000 RPM in 1st
gear. :doh:
Does anyone have any experience with the CVT? Have you done much with the
manual mode? Any thoughts? Don't tell me I should have bought a manual
transmission if I wanted control; I know that! Been there, done that for
decades.
xsicdn
stick wit the manual it will increase you MPG
DARKtEAGLE
Keeping your RPM too low will result in bogging and even more fuel
consumption from what I hear.
What Nissan is this?
newyorker
It's an Altima 2.5SL. It has an instantaneous readout of fuel economy and
an average trip speed / fuel economy ( resettable ). Once I get the hang of
this strange shifter I'll start taking down the numbers along the commute
to work. In a few weeks the daily variances in traffic flow should have
averaged out and I will see which mode gets better mileage. I'm actually
willing to sacrifice a slight bit of fuel economy for a better 'feel'.
xsicdn
I've heard the same thing but always wondered if it was true. On my ride
home from work I get off the highway and drive about 10mi down a 50mph
road. Generally I leave it in 5th and put the cruise on at 53-55. I've
noticed when going up a steep the hill the motor doesn't really struggle,
but the peddle is about floored from the cruise. I always wondered if I'd
be better off downshifting so it wouldn't be peddled so deep and then going
back into 5th downhill and on the flats.
The car got 31mpg last time I checked it so either way I wasn't too worried
about it.
DBain
I doubt you will notice any significant difference in fuel economy from
manually shifting, the computer usually wont let you get into higher gears
annyway, ive experimented quite a bit with different cars at work. The only
thing I have found close to a full manual was BMW's SMG system, which is a
$7,000 option IIRC.
Basically, you cant get into 6th gear at 30mph with some of these Tiptronic
and Steptronic transmissions, as you can with a full manual. The reason for
this is that when you are in that low of a rev range, you are actually
burning more fuel because you have to push the pedal harder to get moving
and therefore are putting more stress on the engine and actually reducing
fuel economy. The car's ECU knows this and doesnt let you do what you
really want.
I would be more concerned with safety, you may find yourself worrying so
much about your shift points that you will be looking at the tach more than
the road.
newyorker
It's the opposite I'm trying to do; I want to keep the revs up between 2500
and 3000 when cornering so that it doesn't bog down when I try to
accelerate out of the turn. So far, I've found that the automatic setting
takes the turn in what amounts to the 4th "gear" setting and the rpm drops
down well below 2000. If I manually shift it into 3rd position before the
turn, I can use the engine braking to slow down and then it's a much
smoother accel with the rpm over 2500 coming out of the turn. I shift up
when it gets to 3000 RPM unless I know there's another turn just ahead.
How many manual transmission drivers look at the tach to know when to
shift? You just feel when it's right ( use the force Luke ). I'm only
quickly glancing so that I can report the numbers here.
In any case, my observation so far is that the fuel consumption has risen
slightly from ~7.6 L/100Km to ~8.2 L/100Km ( I can't be bothered to
convert to MPG ) an 8% increase. I can't say positively it's because of my
manual shifting or because of all the road construction that keep me idling
in slow moving traffic. More testing needed.
xsicdn
I watch the tach to know when to shift. I kinda have to, it boogies from 4K
to 7K.
Enthusiast
I always watch mine, my gearing is hella short so I have trouble keeping it
under 4krpm even when watchingt he tach
newyorker
