Hi,

Have a loan auto version of my own car whilst that is having lots of
money spent on repairs. Not really driven many autos in the past and
never the same make/model/engine.

What does an auto box, in conjunction with the engine management, get
up to? I find that the revs go up to 2,500 +/- 100 rpm (ish) and stay
there over quite a speed and load range. "Load" either being ordinary
acceleration or maintaining speed going up hill (with/without
kickdown).

Is the system going for torque or power? Trying to work out the RPM
range that I ought to aiming for in my manual or cruise at on long
motorway runs, I normally sit at the low 60's and 2,250 ish. I'm
wondering if 2,500 and a few MPH faster will get a noticeable
improvement in MPG. Even 1 MPG better would be over 3% ...

--
Cheers
Dave.

On 19/09/2014 10:13, Dave Liquorice wrote:
Hi,

Have a loan auto version of my own car whilst that is having lots of
money spent on repairs. Not really driven many autos in the past and
never the same make/model/engine.

What does an auto box, in conjunction with the engine management, get
up to? I find that the revs go up to 2,500 +/- 100 rpm (ish) and stay
there over quite a speed and load range. "Load" either being ordinary
acceleration or maintaining speed going up hill (with/without
kickdown).

Is the system going for torque or power? Trying to work out the RPM
range that I ought to aiming for in my manual or cruise at on long
motorway runs, I normally sit at the low 60's and 2,250 ish. I'm
wondering if 2,500 and a few MPH faster will get a noticeable
improvement in MPG. Even 1 MPG better would be over 3% ...

In these days of engine management systems I *guess* they may be trying
to economise on fuel.

Think about a manual; you can maintain a given speed up hill with low
revs high gear more throttle or higher revs lower gear and less
throttle. It isn't immediately obvious which is more economical. But the
EMS knows.

I've just got a Jazz hybrid which is supposed to think about economy all
the time. This has continuously variable transmission and I havn't
driven it far enough to figure it all out. It has an "eco" mode as well
as Drive or Sports on the transmission lever. In Eco, cruise control
does *not* maintain speed up steeper hills, it decides it would be
better to slow down.

In article o.uk,
Dave Liquorice wrote:
Hi,

Have a loan auto version of my own car whilst that is having lots of
money spent on repairs. Not really driven many autos in the past and
never the same make/model/engine.

What does an auto box, in conjunction with the engine management, get
up to? I find that the revs go up to 2,500 +/- 100 rpm (ish) and stay
there over quite a speed and load range. "Load" either being ordinary
acceleration or maintaining speed going up hill (with/without
kickdown).

Is the system going for torque or power? Trying to work out the RPM
range that I ought to aiming for in my manual or cruise at on long
motorway runs, I normally sit at the low 60's and 2,250 ish. I'm
wondering if 2,500 and a few MPH faster will get a noticeable
improvement in MPG. Even 1 MPG better would be over 3% ...

Just wondering what auto it is? The old and now luckily defunct CVT
(rubber band) transmissions did that, but these days most are multi-ratio
types. Either conventional epicyclic gears with torque convertor, or
robotised synchromesh boxes with a conventional but automated clutch. And
neither tends to stay at constant revs. Most conventional ones now lock up
the torque convertor when possible to save energy - it's only really used
at low engine revs and to cushion a change. However, with 5-8 gears there
is more chance of keeping the engine at its most efficient speed, if not
driving hard.

But with a decent modern box it can be hard to tell when it changes gear -
especially if you're not used to an auto.

--
*Bills travel through the mail at twice the speed of cheques *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:

Dave Liquorice wrote:

What does an auto box, in conjunction with the engine management, get
up to? I find that the revs go up to 2,500 +/- 100 rpm (ish) and stay
there over quite a speed and load range. "Load" either being ordinary
acceleration or maintaining speed going up hill (with/without
kickdown).

My car is 3.0 v6 diesel with 7 speed auto, I had a 2.0 v4 diesel with
CVT as a loaner, the smaller engine wasn't particularly underpowered but
it *sounded* like it was labouring, fairly constant high revs, like a
taxi with a clattery engine.

Is the system going for torque or power? Trying to work out the RPM
range that I ought to aiming for in my manual or cruise at on long
motorway runs,

I assumed it was going for economy ...

The old and now luckily defunct CVT (rubber band) transmissions did
that, but these days most are multi-ratio types.

Not that uncommon, the Audi multitronic boxes are CVTs, granted they use
a metal belt unlike the old DAFs. Depending on the mode the user
selects, it can be make to feel "notchy" so the engine changes revs
co-ordinated with steps in the ratio, to feel like a traditional auto
box, rather than a CVT.

Either conventional epicyclic gears with torque convertor, or
robotised synchromesh boxes with a conventional but automated clutch.

Mine's the robobox, with twin clutches, so behind the scenes it predicts
and pre-selects the next gear.

On 19/09/2014 11:42, Andy Burns wrote:
Dave Plowman (News) wrote:



Not that uncommon, the Audi multitronic boxes are CVTs, granted they use
a metal belt unlike the old DAFs. Depending on the mode the user
selects, it can be make to feel "notchy" so the engine changes revs
co-ordinated with steps in the ratio, to feel like a traditional auto
box, rather than a CVT.


The Jazz hybrid CVT has seven notches, and paddles which seemed silly to
me at first, but they do let you use engine braking going down hill.
Curiously, though, this does not show significant recharging of the
battery: you need to use the brake pedal to achieve that.

In message , Andy
Burns writes
Not that uncommon, the Audi multitronic boxes are CVTs, granted they
use a metal belt unlike the old DAFs. Depending on the mode the user
selects, it can be make to feel "notchy" so the engine changes revs
co-ordinated with steps in the ratio, to feel like a traditional auto
box, rather than a CVT.
I'm confused. CVT by definition means constantly variable transmission.
So where do these "steps" in the transmission come from The old DAF
certainly didn't have them.
--
bert

bert wrote:

Andy Burns writes

the Audi multitronic boxes are CVTs,

I'm confused. CVT by definition means constantly variable transmission.
So where do these "steps" in the transmission come from

Since the computer is shifting the input and output cones, it can do it
by "jumping" from one point to the next, rather than by "sliding"
through the ratios ... it can still do that too, but the driver has the
choice.

On 19/09/2014 22:08, Andy Burns wrote:
bert wrote:

Andy Burns writes

the Audi multitronic boxes are CVTs,

I'm confused. CVT by definition means constantly variable transmission.
So where do these "steps" in the transmission come from

Since the computer is shifting the input and output cones, it can do it
by "jumping" from one point to the next, rather than by "sliding"
through the ratios ... it can still do that too, but the driver has the
choice.

Seven "steps" on the paddles of the Jazz; with software to prevent over
or under revving. Left to its own devices, the ratio shifts smoothly,
giving a feel (and sound) rather like having a gas turbine under the bonnet.

On 19/09/2014 11:03, Dave Plowman (News) wrote:
In whill.co.uk,
Dave wrote:
Hi,

Have a loan auto version of my own car whilst that is having lots of
money spent on repairs. Not really driven many autos in the past and
never the same make/model/engine.

What does an auto box, in conjunction with the engine management, get
up to? I find that the revs go up to 2,500 +/- 100 rpm (ish) and stay
there over quite a speed and load range. "Load" either being ordinary
acceleration or maintaining speed going up hill (with/without
kickdown).

Is the system going for torque or power? Trying to work out the RPM
range that I ought to aiming for in my manual or cruise at on long
motorway runs, I normally sit at the low 60's and 2,250 ish. I'm
wondering if 2,500 and a few MPH faster will get a noticeable
improvement in MPG. Even 1 MPG better would be over 3% ...

Just wondering what auto it is? The old and now luckily defunct CVT

We recently had an A class Merc (mkII) hire car that had a cvt, and some
Audis use CVT.

(http://www.audi.co.uk/used-cars/used...cmdc=se_na_re_)

But then, in the last decade, Audi have used *many* types of "auto" box:

Multitronic; tiptronic; CVT; S-Tronic; R-Tronic, and normal automatic,
to name a few....

:-)

(rubber band) transmissions did that, but these days most are multi-ratio
types. Either conventional epicyclic gears with torque convertor, or
robotised synchromesh boxes with a conventional but automated clutch. And
neither tends to stay at constant revs. Most conventional ones now lock up
the torque convertor when possible to save energy - it's only really used
at low engine revs and to cushion a change. However, with 5-8 gears there
is more chance of keeping the engine at its most efficient speed, if not
driving hard.

But with a decent modern box it can be hard to tell when it changes gear -
especially if you're not used to an auto.


nor driving hard.

Modern autos are programmed to change up early, due to the CO2 reducing
maps now used.

David

Dave Liquorice wrote:
Hi,

Have a loan auto version of my own car whilst that is having lots of
money spent on repairs. Not really driven many autos in the past and
never the same make/model/engine.

What does an auto box, in conjunction with the engine management, get
up to? I find that the revs go up to 2,500 +/- 100 rpm (ish) and stay
there over quite a speed and load range. "Load" either being ordinary
acceleration or maintaining speed going up hill (with/without
kickdown).

Is the system going for torque or power? Trying to work out the RPM
range that I ought to aiming for in my manual or cruise at on long
motorway runs, I normally sit at the low 60's and 2,250 ish. I'm
wondering if 2,500 and a few MPH faster will get a noticeable
improvement in MPG. Even 1 MPG better would be over 3% ...


If it's a modern auto, then it's programmed for fuel economy. It will
hunt through the gears, up to 7 I believe in some versions and use the
engine speed/ fuel mix ratio that seems appropriate. Some engine
management systems program themselves to suit the driving style of the
owner over a period of time. Generally using cruise control IME gives
best fuel economy but the results can vary with speed, ie a lower speed
can give worse fuel economy. Mine is most efficient at 55mph. 70mph is
about 10% worse.

On Fri, 19 Sep 2014 14:01:29 +0100, Capitol wrote:

If it's a modern auto, then it's programmed for fuel economy.

Define "modern" it was a W reg Land Rover Discovery II with TD5
engine. The TD5 is a completly "fly by wire" engine. The auto box is
a 4 speed ZF4HP22.

It's pretty smooth at cog shifting under normal driving but put your
toe down going up hill the kick down is detectable or the changes up
when starting slow and accelerating well (for a Discovery...).

I got the impression it was sitting in torque convertor mode most of
the time and hardly ever locking up but could be wrong.

--
Cheers
Dave.

In article o.uk,
Dave Liquorice wrote:
On Fri, 19 Sep 2014 14:01:29 +0100, Capitol wrote:

If it's a modern auto, then it's programmed for fuel economy.

Define "modern" it was a W reg Land Rover Discovery II with TD5
engine. The TD5 is a completly "fly by wire" engine. The auto box is
a 4 speed ZF4HP22.

That is pretty old as regards auto technology. The 4HP22 dates from IIRC
the 80s. My '92 BMW had a 5 speed ZF.

It's pretty smooth at cog shifting under normal driving but put your
toe down going up hill the kick down is detectable or the changes up
when starting slow and accelerating well (for a Discovery...).

I got the impression it was sitting in torque convertor mode most of
the time and hardly ever locking up but could be wrong.

Think that box only locks up in 4th. It probably spends most of its time
in 3rd on country roads.

At one time, autos and diesels weren't a happy combination. London Taxis
being an obvious example. The boxes seemed to be petrol ones just mated to
a diesel - so the characteristics were better suited to a revvy petrol
engine than a slogging diesel. Things are much better these days.

--
*Ever stop to think and forget to start again?

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
Dave Liquorice wrote:

Define "modern" it was a W reg Land Rover Discovery II with TD5
engine. The TD5 is a completly "fly by wire" engine. The auto box is
a 4 speed ZF4HP22.

(Not seeing Dave L's posts, so pinching Dave P's :-))

When I read the OP I immediately wondered if it was a Disco 300Tdi auto
- I've heard that exact description of its operation.

At one time, autos and diesels weren't a happy combination. London Taxis
being an obvious example. The boxes seemed to be petrol ones just mated to
a diesel - so the characteristics were better suited to a revvy petrol
engine than a slogging diesel. Things are much better these days.

Slack torque converters strike me as the worse thing about Diesel auto
combinations - sort of unable to transfer the lo-down torque from one
side to the other. The BMW 330d got given a GM box that was unbelievably
slushy and unpleasant.

--
Scott

Where are we going and why am I in this handbasket?

On 19/09/14 19:59, Scott M wrote:

Dave Plowman (News) wrote:
Dave Liquorice wrote:

Define "modern" it was a W reg Land Rover Discovery II with TD5
engine. The TD5 is a completly "fly by wire" engine. The auto box is
a 4 speed ZF4HP22.

(Not seeing Dave L's posts, so pinching Dave P's :-))

When I read the OP I immediately wondered if it was a Disco 300Tdi auto
- I've heard that exact description of its operation.

At one time, autos and diesels weren't a happy combination. London Taxis
being an obvious example. The boxes seemed to be petrol ones just
mated to
a diesel - so the characteristics were better suited to a revvy petrol
engine than a slogging diesel. Things are much better these days.

Slack torque converters strike me as the worse thing about Diesel auto
combinations - sort of unable to transfer the lo-down torque from one
side to the other. The BMW 330d got given a GM box that was unbelievably
slushy and unpleasant.

our auto deezil freelander has a superb box. Good as the jaguar used to be.



--
Everything you read in newspapers is absolutely true, except for the
rare story of which you happen to have first-hand knowledge. €“ Erwin Knoll

In message , Scott M
writes
When I read the OP I immediately wondered if it was a Disco 300Tdi auto
- I've heard that exact description of its operation.

At one time, autos and diesels weren't a happy combination. London Taxis
being an obvious example. The boxes seemed to be petrol ones just mated to
a diesel - so the characteristics were better suited to a revvy petrol
engine than a slogging diesel. Things are much better these days.

Slack torque converters strike me as the worse thing about Diesel auto
combinations - sort of unable to transfer the lo-down torque from one
side to the other. The BMW 330d got given a GM box that was
unbelievably slushy and unpleasant.

I have to say that my 300Tdi auto Disco Mk1 suits me pretty well,
although it's a shame about the rust. The box does feel slushy, but a
regular route involves an entry into an uphill main road where good
acceleration is needed to match the traffic speed. Flooring the Disco,
it accelerates far better than I can achieve with going through the
gears in my manual Octavia.
I have achieved 33mpg across North Wales and back, where I've been able
to cruise at about 55 the whole way. It locks up at just over 50 in top.
--
Bill

On 19/09/2014 19:59, Scott M wrote:

Slack torque converters strike me as the worse thing about Diesel auto
combinations - sort of unable to transfer the lo-down torque from one
side to the other. The BMW 330d got given a GM box that was unbelievably
slushy and unpleasant.

Many modern diesels don't have any low-down torque.

My son has an Astra diesel. When driving it around he's forever changing
gear, because the power band is so narrow. It needs those 6 gears.

Andy

In message , "Dave Plowman (News)"
writes
In article o.uk,
Dave Liquorice wrote:
On Fri, 19 Sep 2014 14:01:29 +0100, Capitol wrote:

If it's a modern auto, then it's programmed for fuel economy.

Define "modern" it was a W reg Land Rover Discovery II with TD5
engine. The TD5 is a completly "fly by wire" engine. The auto box is
a 4 speed ZF4HP22.

That is pretty old as regards auto technology. The 4HP22 dates from IIRC
the 80s. My '92 BMW had a 5 speed ZF.

It's pretty smooth at cog shifting under normal driving but put your
toe down going up hill the kick down is detectable or the changes up
when starting slow and accelerating well (for a Discovery...).

I got the impression it was sitting in torque convertor mode most of
the time and hardly ever locking up but could be wrong.

Think that box only locks up in 4th. It probably spends most of its time
in 3rd on country roads.

At one time, autos and diesels weren't a happy combination. London Taxis
being an obvious example. The boxes seemed to be petrol ones just mated to
a diesel - so the characteristics were better suited to a revvy petrol
engine than a slogging diesel. Things are much better these days.

The 200TDi Disco auto being an even better example.
--
bert

On Fri, 19 Sep 2014 18:21:51 +0100, Dave Plowman (News) wrote:

I got the impression it was sitting in torque convertor mode most
of
the time and hardly ever locking up but could be wrong.

Think that box only locks up in 4th. It probably spends most of its time
in 3rd on country roads.

Quite probably, 60 on the straight bits but a lot is 50 or less.

At one time, autos and diesels weren't a happy combination. London Taxis
being an obvious example. The boxes seemed to be petrol ones just mated
to a diesel - so the characteristics were better suited to a revvy
petrol engine than a slogging diesel. Things are much better these days.

This combo seemed to work well once you'd got used to it just going
to 2,500 rpm and more or less staying there if accelarating or going
up hill. The drop to idle on over run was a bit of a surprise and I
wasn't convinced I had as much engine braking of my manual. Though if
it did start to run away on a hill it would up the revs a bit and
sort of prevent it.

Anyway it seems that it's probably set up for "economy"/"effciency"
so I'll try a few long cruises at 2,500 rpm in my manual and see what
affect it has on MPG.
--
Cheers
Dave.

In article o.uk,
Dave Liquorice wrote:
On Fri, 19 Sep 2014 18:21:51 +0100, Dave Plowman (News) wrote:

I got the impression it was sitting in torque convertor mode most
of
the time and hardly ever locking up but could be wrong.

Think that box only locks up in 4th. It probably spends most of its
time in 3rd on country roads.

Quite probably, 60 on the straight bits but a lot is 50 or less.

Will probably be in top at 60, unless till accelerating.

At one time, autos and diesels weren't a happy combination. London
Taxis being an obvious example. The boxes seemed to be petrol ones
just mated to a diesel - so the characteristics were better suited to
a revvy petrol engine than a slogging diesel. Things are much better
these days.

This combo seemed to work well once you'd got used to it just going to
2,500 rpm and more or less staying there if accelarating or going up
hill. The drop to idle on over run was a bit of a surprise and I wasn't
convinced I had as much engine braking of my manual. Though if it did
start to run away on a hill it would up the revs a bit and sort of
prevent it.

I'm not well up on the later 4HP22. Early versions were very basic but
later gained electronic control. My 5HP which is on an earlier vehicle
does drop a gear or two going downhill if it is running away and you touch
the brakes.

Anyway it seems that it's probably set up for "economy"/"effciency" so
I'll try a few long cruises at 2,500 rpm in my manual and see what
affect it has on MPG.

If you're not used to an auto but observant of how an engine etc behaves,
they can get some getting used to. Some are absolutely brilliant - doing
more or less what a good driver would do with a manual - but some not so
good. With modern computer control it should be easier to get a good match
between engine and box.

--
*I'm out of my mind, but feel free to leave a message.

Dave Plowman London SW
To e-mail, change noise into sound.

(snip)

That is pretty old as regards auto technology. The 4HP22 dates from IIRC
the 80s. My '92 BMW had a 5 speed ZF.

I thought you had a 1997 528i E39 ???

David

David wrote:
(snip)

That is pretty old as regards auto technology. The 4HP22 dates from IIRC
the 80s. My '92 BMW had a 5 speed ZF.

I thought you had a 1997 528i E39 ???

And before that he _had_ an E34 525i...

--
Scott

Where are we going and why am I in this handbasket?

In article ,
David wrote:
(snip)

That is pretty old as regards auto technology. The 4HP22 dates from
IIRC the 80s. My '92 BMW had a 5 speed ZF.

I thought you had a 1997 528i E39 ???

Had an E34 before - the first production car with the 5 speed ZF, IIRC.

--
*Parenthetical remarks (however relevant) are (usually) unnecessary *

Dave Plowman London SW
To e-mail, change noise into sound.

Capitol wrote:

Generally using cruise control IME gives
best fuel economy but the results can vary with speed

With cruise control, it will maintain speed up hills and then have to
brake once over the crest, so long as nobody is up your chuff you can
beat the economy by losing some speed going up and re-gaining most of it
again on the way down.

On Fri, 19 Sep 2014 20:54:30 +0100, Andy Burns wrote:

With cruise control, it will maintain speed up hills and then have to
brake once over the crest,

AFAIK the cruise on my car has no control of the brake. I shall have
to try it on some of the hills that I normally decend using nothing
but the engine and 3rd gear to brake. Unlike 90% of other drivers who
go down on the brakes. Of course when cruise is using the engine as a
brake it's not burning any fuel or very very little.

Having had the brakes fade on a Mondeo 3/4 the way down an
"enthusiastic" descent of Hartside (1300' in 4.8 miles) I'm a little
wary of over using the brake on a long decents.

--
Cheers
Dave.

Dave Liquorice wrote:

On Fri, 19 Sep 2014 20:54:30 +0100, Andy Burns wrote:

With cruise control, it will maintain speed up hills and then have to
brake once over the crest,

AFAIK the cruise on my car has no control of the brake.

Mine will brake if it goes more than 2mph over the set speed, if you put
your foot down to deliberately exceed the set speed, it refrains from
braking when you let it take over again, until it's been down to the set
speed, the ABS servo is used, you can hear the solenoid clicking, it
also "wipes" the brake discs so there's no delay for them to dry off if
it's wet

Given many people drive the same route over and again, surprised the
cruise doesn't learn where oncoming hills are from the GPS, and then
depending on if you're in sport or eco mode it could keep speed up, or
go for economy,