The "W" button - is it okay to drive at highway speeds?

Hi

Just got back from NorthBay... where it was snowing quite a bit, i've never
had such trouble driving a car in my life... Tried the W button and it
helped a bit getting things going... and I used it on the snow covered
highways at speeds from 50-90kph.... When the roads turned dry I turned it
off.... Even when I had to accelerate to get up hills I didn't have any fish
tailing it was good... But was it okay to just leave it on? I under stand it
locks the car in 3rd for starting up... felt like it went into 4th for the
highway tho.... and considering it was a 3rd gear start the car (960 2.9L)
didn't feel sluggish AT ALL.

 

In an earlier contribution to this discussion,

I would only use it in slippery conditions. By blocking out the lower gears,
it reduces the amount of tractive force available at the wheels, preventing
wheel spin and loss of directional control.

Under normal conditions, with W engaged, the torque converter will have to
work a lot harder every time you start off from rest - generating a lot of
heat and burning more fuel than you do when you use the gears for low speed
acceleration.

 

I had it on in town to get me out of parking lots and maneuver around
corners, then resume down the road... On the highway I only had to stop
twice (at the lights in 2 small towns... I needed the W mode as much as in
North Bay at those stops, one was black ice... ABS was kicked in under light
braking from 100m away doing 40-50 kph, the other was snow).... For the most
part on the highway I was driving in 3rd or what felt like 4th gear.... but
going up hills my RPMs were only 1300-2000 rpm.... usually the tranny would
downshift -I'm glad it didn't.

So basically I drove the car really easy, but had the tranny and torque
converter working extra hard under certain conditions (startups and hill
climbs)?

 

Once you are moving at highway speeds, the W setting makes no difference.
In my experience, fish tailing doesn't happen with front wheel drives. If
you also have front wheel traction control, that will help pull you up
hills. And if you are going up a snowy hill at low speed, the W setting
also helps.

 

The 960 was always a rear drive car... i've had experience with this vehicle
starting to slightly fish tail (well, slide its rear end to one side just a
little bit, then have the limited slip diff kick in and straighten things
out) while just giving the car some mild throttle inputs to accelerate while
at-speed to maintain speed up hills or one flat road surfaces.

Basically I was thinking to myself (I wish I was driving my Golf, I wish I
was driving my Golf for about 45 mins while I got really used to operating a
rear drive vehicle in snow - our 960, despite being fitted with snow tires
has rarely seen action in snow... i've driven on snow with it MAYBE twice or
three times... and only for a few minutes, never with ice under the roads
like yesterday... we have never even tried the W button before... my dad
thought it was a differential locking button)

 

I understand the 'W' button disengages the locking ring on the torque
converter. This normally engages after a gearchange so the change is
smooth, but the mechanical efficiency after is as good as a manual clutch.
Without it the converter is only 80-85% efficient & torque transfer would be
limited, hence it is best permanently disengaged when high torque to the
wheels is not needed.

As far as I'm aware there is no limitation on the gear selection when this
is in use in Drive mode. The older style of auto which has manual 1-2-3
selection is intended for towing or driving up/down hills, where unplanned
upshifts could be dangerous.

 

I´m not too shure about the latest models are you ?



Gert C

Sweden (Used to be a Volvo Country).

 

The 960 and the S/V90 were rear drive 6-cylinder cars... Nothing but.

Who cares about the new ones, if we had the XC70 we want we wouldn't have
this winter driving dilema ;-).

 

The W state is just using the higher gear and skipping first and second.
That is best at highway speeds. It is real gutless at low speeds.

 

In an earlier contribution to this discussion,

At highway speeds it doesn't make any difference - because it won't be using
the lower gears anyway!

W is good for low speed use on surfaces with poor adhesion, because it
greatly reduced the risk of wheel spin. However, it *shouldn't* be used on
good adhesion surfaces because it is gutless and inefficient. Using the
lower gears to generate acceleration torque is far more efficient - and
effective - than generating torque by excessive torque converter slip.

 

Thanks everyone who responded... seems I used it correctly, or so it would
seem. Glad to hear.

 

Perhaps different models / autos in the Volvo range deal with it
differently - but AFAIK W(inter) mode makes it start from standing in 3rd
gear.

It probably does prevent lock-up in the torque converter, too - but is
fundamentally for starting off in a higher gear, in order to alleviate
wheelspin.