[nonsequitur]

MINI One and MINI Cooper are not the only cars which use the ZF VT1 Continuously Variable Transmission. Let's gather some links and comment on these other cars as one way to understand our MINIs better and drive them more effectively.

Based on some discussion in other threads, the ZF VT1 CVT may have different components in the different cars where it is being used. I edit this comment into this post on 11/11/2003 so that we are all aware of the work underway to understand this situation.

The BMW/MINI transmission is definitely model designation "VT1F".

Because we're stepping outside the threads of MINI2, be sure to include a link to the source of information if you have one.

[nonsequitur]

Here's a first contribution.

MG TF 120 Stepspeed: MG TF, Menu, MG TF Models, 03
http://www.mg-rover.com/servlets/com...=en_GB&make=mg


From the MG Owners Club
http://www.mgcars.org.uk/cgi-bin/gen...g/changing.htm


We have all sat in front of our televisions on Sunday afternoons watching the Grand Prix drivers shifting up and down with their steering wheel paddles. Instantaneous changes - or drive by wire, as it has been dubbed - is something that is a fascinating concept and now that MG has followed the growing move towards CVT transmissions, it is something which we can all experience.

There will always be diehards who will argue that any form of automatic transmission for a sports car is a contradiction in terms and that the legendary four-on-the-floor is the only way to go. But they would be forgetting such advances as the preselector gearbox, which helped make the MG K3 so competitive, the overdrive fitted to countless MGBs and Cs and the automatic gearboxes that made the MGC an even more relaxed long distance cruiser. And no-one will devalue the Mercedes-Benz SL and SLK for being automatics, while Porsche with its Tiptronic transmission has added enormously to the sports car driving experience.

Continuously Variable Transmission technologies are very much the significant motoring advances of the last years of the century, the primary reason being increasingly sophisticated electronic control systems, which have transformed the functionality and performance of the traditional automatic gearbox. Combining this with CVT, has produced a transmission that is both technically innovative and a pleasure to drive.

MG transmission engineers have worked with transmission supplier ZFST of Belgium to produce what is surely the most innovative gearbox seen on a production car and it provides the driver with a variety of options that may be readily selected to meet road conditions or driving mood.

What do you get with the Steptronic MGF? For a start, it is based around the MGF 1.8i - it is unavailable on the VVC. MG claim that the MGF Steptronic is the first sports car to give the option of either automatic transmission, ideal for congested urban use, or a six-speed manual sequential gear change for optimised sporting performance.

There are two modes to the automatic, Drive and Sport, while in the Steptronic mode gear changing is either by the conventionally positioned gear lever or shift stick, or by the steering wheel mounted controls. In Steptronic mode there are six pre-set ratios on the CVT (continuously variable transmission).

How the three Steptronic modes operate

The first thing to say about the Steptronic system is that it is totally driver-friendly. Anyone approaching it for the first time need have no worries whatsoever. So, having settled into the cockpit, what are the changes and mode of operation?

This is a two-pedal car, the brake being large in terms of the normal manual transmission car. The foot rest on the transmission tunnel remains and this is the position for the now redundant clutch foot.

The Steptronic gear lever provides a normal CVT automatic selector pattern of PRND (Park, Reverse, Neutral and Drive). If D is selected, the transmission operates in the normal automatic mode, with the ratios adjusted to keep engine revs below 4,500rpm at road speeds under 70mph. Above this figure, the transmission will employ engine speeds in the 4,500-5,000 rpm band. This combination provides relaxed and economical driving in even the most congested traffic.

For greater performance, the lever is moved left from its Drive position into Sport CVT mode. Once this has been carried out, the peak engine power speed of 5,500rpm becomes available and this transforms the character of the car by providing maximum acceleration, because the engine can be held at peak power, while the gearing is progressively increased.

To drive the car in 'Manual' mode, this is achieved by moving the gearlever, or one of the two steering wheel buttons. For both the gearlever and steering wheel controls, the method is the same, namely: forward for an upshift and rearward for a downshift. The driver is then able to select from the six gears available, in exactly the same way as a six-speed gearbox. The system permits the use of engine speeds of 5,500-6,000 rpm. Although there was considerable debate at MG over whether the two buttons should each have a single function, it was decided that it would be preferable for both to have that ability to change up or down, leaving the driver to decide whether he or she was more comfortable with the left or right.
To change from the manual or CVT Sport mode back to the normal CVT, the driver simply moves the lever back to the right, to assume the PRND plane. For safety reasons, the car will only start in the Park or Neutral settings, so the initial star-up is always in CVT mode.

In front of the driver there is an LCD display in the instrument panel. This shows which mode has been selected. D or D Sport is shown for the CVT modes, while the numbers 1-6 are shown in the manual mode. LED indicators light up on the base of the floor gearshift to confirm selection of either the P, R, N or D positions, or the M/S Manual or Sport settings.

On the road

Inevitably, moving from a manual transmission car to the Steptronic MGF is something of a radical departure. So it is best to think of it initially, as a conventional automatic. Because the power is delivered constantly and the gear changes occur in stepless fashion, this is the most effortless way to enjoy this new MGF derivative.

Move the lever across what would be the gate in a conventional gearbox, select Sport mode and there is a dramatic change of character. The entire car becomes more alive, urging the driver to exploit the performance to the full, certain in the knowledge that all worries about being in the right gear at the right time have been taken care of. On a road that a driver does not know, the MGF in this mode allows full concentration on position, braking points and observation and it is a highly rewarding - and quick -method of progress.

Having tried the car in both the CVT modes it is time to really utilise the Manual mode of the transmission. With fingertip control, it is a matter of simplicity to go up and down the six speeds at will, enjoying the transmission to the full or honing driving technique to perfection. But quite apart from playing at being an F1 or BTCC driver, there are very definite benefits from the manual mode. Being able to change gear while keeping both hands on the wheel can be an additional safety feature on an unknown road, particularly if a corner suddenly tightens or a gradient changes on a mountain pass, for example. Or, in the case of driving the car on a snowy slope, being able to go down through the gears utilising the engine braking while maintaining full steering control and without touching the brakes, can literally be a lifesaver.

How quick is the MGF Steptronic? The table will show that in terms of figures, it is slower than the standard MGF in both top speed and 0-60mph acceleration times. But in the real world of driving, the MGF Steptronic feels exactly the opposite. Because the power is constantly on tap, progress on any drive, particularly across country, is remarkably rapid and it was the opinion of several drivers who were at the wheel for considerable distances, that it was probably quicker over the ground than its manual counterpart. In terms of economy, the MGF Steptronic suffers slightly in relation to its standard brother. But choosing the mode for the conditions, standard automatic for the motorway haul, for example, will see this minimised.

Could you live with the MGF Steptronic? There is one infallible answer and that is to drive it. You will discover that it is not only enormous fun but that it adds an entire new perspective to the MGF. When the car was launched back in 1995, everyone who drove it regarded it as redefining the sports car experience and with the new MGF Steptronic, the game has moved forward in a giant leap. That is not to say that everyone will want to choose this version of the MGF - for ultimate performance, the VVC will remain the choice. And there will be some who will want to stay with the manual MGF 1.8i. For both of these groups, MG will continue to cater.

What the MGF Steptronic undoubtedly does is to further widen the appeal of the MG marque, notably to those who might never have considered a manual sports car for their driving pattern, a slow urban commute being a case in point. It will also gain even greater appeal as a second or third car in a family environment, being equally suitable for both established and those less experienced drivers. Those who take a test drive when the MGF reaches the showrooms in October this year will find it difficult not to be impressed.

MGF STEPTRONIC- Performance and Economy

MGF 1.8i Manual Steptronic
Performance
Maximum Speed 193kph/120mph 190kph/118mph
0-100kph/0-60mph 9.0/8.5 seconds 10.0/9.5 seconds

Fuel Consumption
Urban 10.2 litres/100km/27.8mpg 11.6 litres/100km/24.4mpg
Extra Urban 5.7 litres/100km/49.3mpg 6.4 litres/100km/43.9mpg
Combined 7.4 litres/100km/38.3mpg 8.3 litres/100km/34.0mpg

Changes for 2000 Model Year MGF Include 3 Year Warranty

As the MGF completes its fourth year of production at Longbridge, MG Cars have announced a number of significant changes to the MGF, not the least of which is the introduction of the three-year warranty. This has no limitations on mileage or items covered in the first year, while the second and third years of ownership are protected by a dealer-backed warranty up to 60,000 miles.

While the basic outline of the car remains unchanged, testimony to the rightness of the original design, the introduction of the Steptronic transmission is seen as a major step.

[Spookyfish]

Here's another link on the MG
http://www.sae.org/automag/techbriefs_10-99/08.htm

Ford is mentioned on page 3:
http://www.autotechdaily.com/pdfs/T01-08-02.pdf

Variant of the CVT for the Ford Focus:
http://www.autotechdaily.com/pdfs/T01-22-03.pdf

Talk about a 210Nm variant in the left column on page 3:
http://www.lcda.fr/pdf/ing-gb.pdf

[Spookyfish]

For our Dutch readers:
http://www.bibendum.demon.nl/octopus...-nr16-2002.pdf

[Sejanus]

Quote: Originally Posted by nonsequitur

To drive the car in 'Manual' mode, this is achieved by moving the gearlever, or one of the two steering wheel buttons. For both the gearlever and steering wheel controls, the method is the same, namely: forward for an upshift and rearward for a downshift.

Isn't that the opposite of our MINIs?

Great post by the way. Thanks for hunting that down.

[nonsequitur]

Yes. And it is this kind of detail that will eventually pull together a complete picture for us. The ZF gearbox is very flexible, and adaptable to different customer (car manufacturer) requirements. It will allow many different Steptronic "gears" as an example (up to 12, I believe) although MINI and MG are using 6.

[Snake]

Quote: Originally Posted by Sejanus

Isn't that the opposite of our MINIs?

Great post by the way. Thanks for hunting that down.

yes it is

[nonsequitur]

I thought there was an asian-produced vehicle and other european-produced vehicles as customer manufacturers, but I was told today that the ZF VT1F CVT is used in three vehicles currently:

MINI Cooper CVT

MINI One CVT

MG TF 120 Stepspeed


Does anyone have a source to confirm this, or some links to manufacturers using a ZF CVT? There are other ZF customers, but they are not using the same transmission as ours.

[Spookyfish]

I found this link just now:
http://www.ai-online.com/issues/arti...tail.asp?id=77

[nonsequitur]

That is a VERY interesting article. It confirms the future direction outlined in several calls I've had, and reinforces the success of the VT1F that we are exploring and sharing here on MINI2. I think it hints at some of the observations we would like to have worked on too.

A positive read. Thanks!

[PigLick]

That is an interesting read, especially about their new CVT with the torque converter. I don't know much about trannies, so maybe someone can give some input on this...but isn't a torque converter the big contributor to lower efficiency and "slushy" feelings of automatics? I find it interesting that he says "Especially in North America, we now believe that CVT has to have a torque converter." As has been mentioned before on this site, many people in America seem to prefer that slushy, disconnected-from-the-road feeling that regular old auto trannies give you, and I wonder if that's what they're doing with the new CVT to appease that crowd.

PigLick

[Spy Car]

Quote: Originally Posted by nonsequitur

There will always be diehards who will argue that any form of automatic transmission for a sports car is a contradiction in terms and that the legendary four-on-the-floor is the only way to go.

What's wrong with these narrow minded diehards?

Don't they realize 6 on the floor is also good way to go in a sports car?

Quote: Originally Posted by nonsequitur

And no-one will devalue the Mercedes-Benz SL and SLK for being automatics.

No one???.....are you sure?

Quote: Originally Posted by nonsequitur

..... while Porsche with its Tiptronic transmission has added enormously to the sports car driving experience.

LOL......I have to admit you had me going there for a minute

[nonsequitur]

The only disclaimer I must add is the one posted with the material you pulled out from the article above: "From the MG Owners Club"

[CooperS4us]

I think Spy wants to get a rise out of Johnwald, but he will not succeed so it seems....

[Spy Car]

Quote: Originally Posted by CooperS4us

I think Spy wants to get a rise out of Johnwald, but he will not succeed so it seems....

Moi?

You know I love you guys

[Spookyfish]

Quote: Originally Posted by PigLick

That is an interesting read, especially about their new CVT with the torque converter. I don't know much about trannies, so maybe someone can give some input on this...but isn't a torque converter the big contributor to lower efficiency and "slushy" feelings of automatics? I find it interesting that he says "Especially in North America, we now believe that CVT has to have a torque converter." As has been mentioned before on this site, many people in America seem to prefer that slushy, disconnected-from-the-road feeling that regular old auto trannies give you, and I wonder if that's what they're doing with the new CVT to appease that crowd.

Yes, a torque converter gives less 'feel'. But a torque converter has it's advantages. It converts torque. Meaning that when you rev the engine up by slamming the accelerator, but the car is stationary, the torque converter wil transform the differences in rotation between engine and wheels into torque, often resulting in a whiplash .

[PigLick]

Right, but can't the same thing be achived with a clutch? Neck-snapping acceleration is certainly not unique to cars with torque converters (and, if I'm not mistaken, nearly all autos accelerate less than manuals).

PigLick

[Spookyfish]

A slipping clutch will do roughly the same but also wears out. I think the advantages (smooth and no take-off delay) of a torque converter don't weigh up against it's weight and mileage disadvantages in a car like the Mini.

[Harley Jetzer]

The Lada 110 auto is using the same box, its 1500cc engine has even more hp (92) than our mini one. It is even more clever programmed, as it it doent go higher in the revs than max hp revs. Our mini one goes in kick down up to 6K but max hp are at 5.3k. Accelelartion is 1.5 sec faster with the kick down blocked! up to 100km/h. So we blocked the kick down as it is absolutely useless !

[nonsequitur]

How have you "blocked" kick down? Something physically behind the e-Pedal?

You might post over on the Objective Testing thread about your acceleration tests. I'd like to read about what you did, and what results you found in each configuration.

Thanks for the lead to Lada. Is there an English-language website forr info on the cars?