[nonsequitur]

Has this question, originally posted by ipoulin, really been answered?

It appears that the CVT's behaviors are the same in all markets.

The Cooper CVT shows a "shifting" sensation when throttle is to the floor (past the kickdown detent) in D, SD, or Steptronic, each mode a little different.

If throttle is held just shy of the detent in D or SD, the engine comes up to a maximum torque rpm (higher in SD) and holds there while the transmission manages very smooth CVT acceleration.

Does everyone agree this is true?

[adgrimes]

I agree with you John. All the time I was reading this thread, I was thinking that everyone who mentions the "shifting" behavior, is also saying that this happens under rapid acceleration (ie. flooring the throttle, past the indent point...)...
Flooring the throttle takes you straight past the indent point, without you even feeling it clicking...
Just before the indent, in D, the car will rev to about 4500RPM's and hold those revs, while accelerating... The CVT is strange in that you get no feeling of acceleration at all in D... A little more in SD, but still not like a manual gear shift.
If you want the feeling of acceleration and "shifting" then use Steptronic... Thats why its there isn't it???

[nonsequitur]

Steptronic is certainly one way. It is intended to bring virtual manual "control" to this transmission, and it works. You can drive the car with the throttle (manage weight transfer in corners) in Steptronic - it's fun too.

These different modes are more different than I initially believed. We did one day of dyno testing to verify the behaviors under strictly controlled and repeatable conditions.

D (Drive) manages engine power differently than the other modes. I've been told there is a 'smooth to 50' software function that is intended to deliver comfortable and predicable acceleration in D. This seemed to show in the dyno readouts; lower power than SD, lower RPM "shift" when floored.

SD (SportDrive) gave the best acceleration when throttle was held at the detent. Flooring the throttle produced the behaviors we've talked about, but they weren't really faster.

[brave1]

I'm wondering if what I'm experiencing is because I have the CVT...it's the stutter step feeling when I'm going very slow in traffic..kinda makes it feel like I'm taking my foot on and off the gas multiple times, when I'm not. Even my passengers have noticed it and I had to convince them it isn't me!lol Anyone else have that issue?

[nonsequitur]

There are several different "software" functions in the EMS2000 (which carries the MINI software versions that get so much attention in these threads) AND, separately, in the ZF VT1F CVT transmission itself to manage certain aspects of the drivetrain. We're still trying to get this sorted out: which part of the system does what function, how does it do it, and why does it do it are questions.

Very slow speeds (indoor parking garages, etc) are very difficult for CVTs to perform smoothly. There are control loops [hydraulic in the transmission, I think] to balance and smooth the pressures used to adjust the variators (belt positioners). The computer program injects itself into this slow-speed transmission process as well, which means that the programming, which we've seen change from the early versions to 34.x, has changed and improved these behaviors.

[brave1]

So I guess I'm stuck with the stutter step effect huh? Well, I'll just have to look at it as a MINI thing, and be happy;-) Thanks for the info john.

[nfo]

i think you just have to "really" know how to drive the cvt! i've learned how to avoid the stutter completely!

[nonsequitur]

brave1. No you're not stuck with it, because as the car continues to be sorted, these behaviors are being worked out of the systems. Which software version do you have installed?

nfo. I'd ask you to put your technique into a post on the Driving Technique thread for everyone to benefit.

[brave1]

John ..not sure which software version I have..how do I find out? I'm pretty sure it isn't my driving technique since there is not much I can do about stop and go traffic..lol ;-)

[nonsequitur]

brave1. I'd also guess it's not your driving technique. You're feeling the systems (software and hydraulic) adjusting for the slow speed conditions that you are driving at that moment.

Software version comes from a call to your dealer. If you don't have at least 33.2 (the most recent is now at 34.x), then you really must get the upgade, and it will make a difference in your situation.

[brave1]

I will ask my dealer and see what they say..do they upgrade for free? I still love driving my Cooper though!;-)

[nonsequitur]

Has there been any more opinion on this subject recently?

I think we concluded that the ZF VT1F CVT, as implemented by MINI/BMW, exhibits a "shift" behavior in all markets if the e-Pedal is floored in D, SD, or (as required) in Steptonic. I still have 33.2 in our car, but no reports I've read on 36.0 indicate a change in this characteristic. It's still there - correct?

##### MGF, MG-F
What about the ZF VT1 CVT that installed in the MG-F? Does anyone have one of these cars, or know someone who does? How does it work there? What driving behaviors does it have?
#####

[Spookyfish]

I just found this:
http://cvt.com.sapo.pt/why/why_cvt.htm

[Spookyfish]

Also found this:
http://www.automobilwoche.de/cgi-bin...pl?newsId=1827

AltaVista's Babel Fish translation:

ZF transmission for US Ford models
Aggregates for the Freestyle and the Fivehundred planned
Klaus Dieter Floerecke
Automobile week /14 April 2003

Friedrichshafen. ZF goes shortly in the USA with its stepless automatic transmission (CVT) into series. According to data of Michael Paul, Technikvorstand of the ZF Friedrichshafen AG and directors/conductors of the range passenger car propulsion technology, the aggregates in the new Ford models Freestyle and Fivehundred are used. In Europe the circuit breakers become already in the Rover 216, which roadster uses MGF as well as in the mini of BMW.

At present ZF works on intensified versions of the CVT transmission. Without needing additional building area, these are to then cover even in its smallest version "VT1F" torques of up to 210 Newtonmeters. At present the VT1F transmission masters only torques of up to 175 Newtonmeters.

[jeremyp]

Can anyone answer nonsequitur's question?

Is there anyway the annoying (IMHO) shifts when you floor it or in SD mode can be removed to provide a quick accelerate without simulates shifts (and delays)??

[Spookyfish]

Not anytime soon I suppose. One remedy is to not floor it but hold it shy of the kickdown button. Best results in SD.

[nonsequitur]

I just got back from three days in Portland, two with huge seat time on the track. Each time out, I'm more impressed with the MINI, and each time out I'm more impressed with the CVT. This is a very capable car -- just as most here have said.

I'm going to build an entry to the Driving Technique thread about some observations by other school participants and instructors riding with me.

I'd like to get rid of the full throttle "shifting." This behavior isn't quicker, and it's more effort than should be necessary to consistently hold the pedal at detent. With that said once, it is possible to do it (for two days!) and thoroughly enjoy a wonderfully quick machine.

I enjoyed lapping with a MINI Cooper S to prove out that 48bhp only makes a difference on the long straights -- and that tight corners winds 'em back in!

The paragraph that belongs in this thread is this one: Many people rode with me. They were ALL impressed with the "CVT" behavior; motor reved to max torque and held there while the transmission was managed to deliver acceleration. The only ones who had ever experienced this idea were two who had driven the Audi FWD Sedan CVT.

We have a unique car, a very capable head-turning car as well -- a "surprise" to most people. It's lots of fun to be in this position.

[Spookyfish]

You said: They were ALL impressed with the "CVT" behavior; motor reved to max torque and held there while the transmission was managed to deliver acceleration.

I hope you mean max power and slapped it in SD. It will hold max torque in D and max power in SD.

[nonsequitur]

We were in SD the whole weekend. I decided not to confuse things with too many experiences.

From our dyno testing in July when this MINI Cooper CVT was strapped down to find torque and horsepower, our car displayed maximum torque (110.4ft-lbs) in SD at 5500rpm. This SD result was higher than the tested maximum torque (101.2ft-lbs) in D at 5250rpm. Same conditions, same techniques.

We found both torque and horsepower tested higher in SD than D. The cutoff was also much sharper in SD. A reason for this must be that the EMS2000 deals the deck differently for SD than it does for D, related to emissions, economy, smoothness, etc.

The reaction from each and every person who rode with me (7, I think) was a measure of surprised curiousity. It was interesting, ... because they had never seen anything like it, and most did not expect to feel the performance and high cornering limits.

[nonsequitur]

Here's another old thread, brought forward to refresh this "Wish" for a car that uses the ZF VT1F Continuously Variable Transmission as it was engineered to perform. Re-reading this thread was interesting because it's apparent that this group works at a question until it is better understood! Compliments to all!