CVT driving technique

[nonsequitur]

Here is my understanding of how the US specification Cooper CVT transmission works (minus any technical details from inside the box or software programming), borrowed from a thread in the COOPER section. See comments at the bottom about driving it in different situations.

Your comments?

1.
The normal "D" mode (CVT automatic) behaves differently depending on the various inputs to it and the options onboard. Throttle position is the big one.

1.A.
If you launch at about 3/4 throttle, the transmission manages rpm and belt position to get you going, and then it runs rpm up to about 4000rpm -- and holds it there, steady. The computer then manages accelleration by Continuously Varying the Transmission belts -- smoothly. No "gear" changes here. Smooth, controlled, "quick."

This seems almost spooky the first time, but it is really quite effective. Accelleration is brisk, and smooth, kinda high tech too. This is the CVT Motoring range. Fun.

1.B.
Launching at full throttle gives a very different experience. The transmission looks for torque and horsepower to build speed more quickly. This has the effect of producing two or three virtual "gears" in the runup to legal road speeds. There are quick adjustments to belt position, and the effect is not "silky smooth" as in 1.A. above, and it is not like 2. below either.

This is the area may still need some programming changes.

2.A.
The right hand side gives you "SD" (Sport Drive) which includes the virtual sequential six-speed (steptronic-like), allowing manually selected upshifts (+) and downshifts (-) provided the engine rpm is within the programmed range.

2.B.
The CVT will also manage shifts in Sport Drive. On ours, it performs full throttle upshifts EXACTLY at 6000rpm, no more, no less.

Comments
I'm still struggling to learn how to drive the modes properly.

SD appears to function as expected at medium speeds. I love how you can hold a "gear" and modulate the throttle to help rotate the car in the wet, and to control speed on downslopes or in traffic. Very cool.

I'd be interested in any comments on technique. Left foot braking? Throttle blips?

We have NOT figured out how to drive at lower speeds with bigger inputs. A coned som (autocross course) is an example where the transmission tries too hard to catch up with inputs, and it it gets confused. Now I've always said that it's the driver's responsibility to figure out the machine, but at this point I haven't. I'm getting too much management from the CVT programming, which creates attempts to "shift", etc. Any suggestions?

All in all, the CVT is a very interesting package. The car scoots, it works real well in the middle of the city, and its great fun at medium speeds in the twisties, ...

[elmadi]

Quote:

Originally posted by johnewald
Here is my understanding of how the US specification Cooper CVT transmission works (minus any technical details from inside the box or software programming), borrowed from a thread in the COOPER section. See comments at the bottom about driving it in different situations.

Your comments?

1.
The normal "D" mode (CVT automatic) behaves differently depending on the various inputs to it and the options onboard. Throttle position is the big one.

1.A.
If you launch at about 3/4 throttle, the transmission manages rpm and belt position to get you going, and then it runs rpm up to about 4000rpm -- and holds it there, steady. The computer then manages accelleration by Continuously Varying the Transmission belts -- smoothly. No "gear" changes here. Smooth, controlled, "quick."

This seems almost spooky the first time, but it is really quite effective. Accelleration is brisk, and smooth, kinda high tech too. This is the CVT Motoring range. Fun.

1.B.
Launching at full throttle gives a very different experience. The transmission looks for torque and horsepower to build speed more quickly. This has the effect of producing two or three virtual "gears" in the runup to legal road speeds. There are quick adjustments to belt position, and the effect is not "silky smooth" as in 1.A. above, and it is not like 2. below either.

This is the area may still need some programming changes.

2.A.
The right hand side gives you "SD" (Sport Drive) which includes the virtual sequential six-speed (steptronic-like), allowing manually selected upshifts (+) and downshifts (-) provided the engine rpm is within the programmed range.

2.B.
The CVT will also manage shifts in Sport Drive. On ours, it performs full throttle upshifts EXACTLY at 6000rpm, no more, no less.

Comments
I'm still struggling to learn how to drive the modes properly.

SD appears to function as expected at medium speeds. I love how you can hold a "gear" and modulate the throttle to help rotate the car in the wet, and to control speed on downslopes or in traffic. Very cool.

I'd be interested in any comments on technique. Left foot braking? Throttle blips?

We have NOT figured out how to drive at lower speeds with bigger inputs. A coned som (autocross course) is an example where the transmission tries too hard to catch up with inputs, and it it gets confused. Now I've always said that it's the driver's responsibility to figure out the machine, but at this point I haven't. I'm getting too much management from the CVT programming, which creates attempts to "shift", etc. Any suggestions?

All in all, the CVT is a very interesting package. The car scoots, it works real well in the middle of the city, and its great fun at medium speeds in the twisties, ...

Interesting thoughts. I do agree the CVT does suprises me.

[cooper4us]

The CVT is not your regular hydraulically operated slushbox.

It has the feel and engine braking power effect of a manual but without the clutch pedal.

[nonsequitur]

How about driving technique hints? Has anyone put the CVT through its paces at a track? At an autocross? I haven't yet.

We're struggling with figuring out how to drive it effectively.

I've had manual gearboxes all my life, so I mash on the throttle [too much], or lift off the throttle, expecting weight transfer. The problems are most pronounced in low speed acceleration situations, the car wants to help me too much. An autocross will bee tough?

Great fun today in medium speed (40mph+) open corners, in the wet. In SD, I could easily throttle-steer my way around. An honest hoot. In this situation there was momentum on the car, so all I was asking from the throttle inputs was weight transfer, not speed change. The CVT worked beautifully, held tightly to a "gear", and gave me weight transfer to steer around the corner. Fun!

[nonsequitur]

I am restarting this subject based on the careful, helpful advice from several people today in the thread COOPER, Cooper CVT objective testing.

We have discovered a new car -- in the Cooper CVT with 32.1 we already had in the garage! I feel a bit embarrassed, especially after writing some of what has been written (even right above), but them's the facts so ...

I didn't how the Cooper CVT transmission worked!

I was using only two (2) of the three (3) distinctly different modes available in the CVT.

The MINI Owner's Manual (p.46-48) does not really explain these modes, or how to use them effectively. With all the attention on the software problems, we haven't focused on the very engaging side to the CVT transmission.

1.
Drive ("D" in the speedo) is the Continuously Variable Transmission mode.

2.
Sport (some say SportDrive, "SD" in the speedo) provides very similar functionality as D, but with a much more aggressive map, at consistently higher engine rpm to give more horsepower to the computer. This is engaged by pushing the shift lever to the right, but no push or pull (this is the mode I never found)!

3.
Steptronic ("1, 2, 3 ,4 ,5 or 6" in the speedo) is engaged from the S (right) shift lever position which first displays "SD", then the virtual gear selection by a single push or pull on the shift lever.

My stories were generated from the Steptronic mode, which is not great off the line, but does everything well as a manual would too in the medium speed stuff we were driving.

This Sport mode is much smoother. It shifts at 6000rpm but the belt adjustment is controlled much better. There is engine braking too, I think not a sharp as Steptronic, so throttle-steer part may work well in Sport also.

Very, very cool! Thanks to those who helped me on this.

MINI should be talking about this differently, and much more.

[cooper4us]

I think that the MINI sales brochures don't really talk much, or anything at all, about all the virtues of the CVT transmission. I think MINI should do a better job in giving the CVT its rightful place within the line-up.

I am glad now you have discovered the full potential afforded by the CVT. Have fun!

[cjay]

The MINI Owner's manual does not say much about CVT but it has been fun working out how the get the best out of it!

I have my own views on CVT...

D stands for cruise mode and is what you put it in when you look at the fuel consumption it is twice what you thought it would be....

SD stands for FUN! It goes much harder :-)) great for when you don't care about fuel economy... or your trying to keep up with a Cooper S

Steptronic stands for Woo Hoo! here comes the redline again!

c.j.

[nonsequitur]

That's great!

Now, as several of you realize, I'm going to re-start my learning of this wonderful little car's CVT transmission. We were truely using it so incorrectly, by "just using" Steptronic once SD was selected. We were never shown SD did anything (we were actually shown only Steptronic) and the Manual is very poorly written on this CVT. It's no wonder why I started a couple of these threads on the CVT, and commented as I did in several others.

We have another car now, much more technically interesting, far fewer concerns than I was carrying around now that the big software issues seem to be resolved.

####
So, to help me find the best techniques, and to get this thread back on point with how it started out, do you have suggestions?

At least three areas where ideas seem to be needed:

Launch. SD is better than D and, I think, Steptronic, but it still bogs down as the computer finds rpm and belt position. Brake plus gas, then release the brake? Any cautions?

Low speed tight corners. Your right foot wants to flail on the throttle (on/off the gas) in this situation, but the best technique may be much lighter applications, maybe even use left-foot brake. How does the computer read these inputs? What does it send as control commands? How can I minimize the computer's attempts to "kick down" or readjust the CVT belt position?

Higher speed open corners. The answer here seems to be very smooth driving. It is possible to get weight transfer with the throttle in both SD and Steptronic (even D frankly), so attention seems best put to correct placement on the road, correct speed on entry (not too much brakes because the MINI can carry so much speed), and smooth application of throttle on exit.

I'm off for another drive ...

[BCMINI]

Over the course of about seven months I have autocrossed and taken our MC with the CVT to open track events. The CVT is a great transmission with a lot of potential. I do all the racing with the CVT in Steptronic mode. When I am at the line at autocross I hold the brake while appyling the gas to about 2000-2500 RPMs. I have had no problems. One interesting thing I have noted when racing is the Mini almost has two full throttle positions.
For example: If I am in 3rd gear and slow to a speed that would be fine for 2nd gear (high RPMs) but if I do not downshift(or if the computer does not downshift for me, which it will do if you slow too much) when I try to accelerate it feels slow and bogged down. If I have the throttle at full, but it still feels bogged down you can push the throttle past this position and the RPMs will increase very quickly, even though I have never looked right at this moment I assume it downshifts then quickly upshifts back into the gear I had it in. Note: you can not shift when you have it in the second throttle position, I have tried many times.
A way I shift smoothly in the Mini when in steptronic mode is to lift very, very lightly off the gas when shifting. I lift of the gas to the point where I am maintaing speed, not accelerating or am I off the gas.
If I do not want the computer to "kick down" a gear and want to run at lower RPMs, I accelerate a little. Not enough to trigger a response from the computer thinking I want to accelerate hard though.
I hope I help by giving insight to my driving style. The steptronic mode is a blast to drive on the street or the track.

[nonsequitur]

A very nicely detailed post, exactly what was hoped for out of this thread. And, great feedback on really driving the Cooper CVT. Thank you BCMINI (Vancouver?)!

Please clarify the two throttle positions. There is a distinct detent position in the electronic throttle pedal. 0-80% or so, and then full throttle if pushed further (generates kickdown). Is the first "full" position in the less-than-detent range, and the "second" position when you've pushed beyond it?

I'll hopefully have a chance to work with these ideas next weekend in a track day my young bride said I could run at Pacific Raceways (Kent, WA) which can be fairly technical because of the elevation changes.

[BCMINI]

The two throttle positions you posted about is what I was talking about, I didn't know what they were called.

You should have a lot of fun on track.

p.s. not Vancouver.

[nonsequitur]

MINIBC; I reread your earlier post on feathering the throttle. All of this has application on the street, and it may be easier to focus on the subtly of it where you can pick out one piece at a time (like the commute to work). It will be fun try this out.

You mentioned autocross. This is wonderful example of a Low speed tight corners situation. Do you have any specific suggestions, or experience to share, on the CVT in this environment?

[BCMINI]

Right now one of the only things I can think of that is CVT specific is that the computer will shift to higher gear if you run at redline for a couple of seconds. It is not fun because in that situation you are usually using the power to pull through a corner and the quick reduction in RPMs will want to throw the back out, like lifting of the throttle. Watching your gear and RPMs is important in autocrossing the CVT. It takes some trial and error to find the right RPMs for every turn. Sometimes you get into the situation where you have use that "second" throttle.
Don't forget the CVT has wonderful engine brake. If you get into a turn to hot and are braking hard, when you RPMs lower some you can downshift to aid in slowing down. Use caution though. Don't want your needle to fiy of the tach or upset the balence to the point of spinning out. Using engine brake is very helpful when running on the track in the rain. It helps so you don't have to brake as hard. It would be best to do it while going straight. Can't think of anything else. I will post if I do.

[nonsequitur]

An amazing day. We spent all day running 201 track miles at Pacific Raceways (formerly Seattle International Raceway) in a Driver Education event organized by Northwest Audi Club. This is a 9 turn, 2.25mi, under-renovation track with elevation changes. The Audi Club and the Don Kitch organization did a great job with lots of driver feedback and instruction, in sessions that included lots of rain (great for learning the car) and significant sun breaks.

I made lots of progress on trying to understand the CVT.

There are three very-distinct modes just as we've distilled in all these posts: Drive, SportDrive, and Tiptronic.

BUT, the biggest puzzle of the day turned out to be the throttle. I've used this electronic device incorrectly too. It took until later in the day to find a [secret?].

I was unable to make anything work effectively through a series of linked corners (5A, 5B, 6 and 7). D was simply a poor choice on the track, period. SD changed the maps for engine and transmission; it felt tighter, much more controlled, sharper (as you would expect), but it wanted to "adjust" inappropriately and consistently in these corners. Tiptronic worked as advertised, but it would not hold a "gear" if the rpms were held high; the transmission would "shift" on its own.

To work on these symtoms, we tried throttle input very early (to "spool up" whatever had to adjust) so that the thrust needed was there at the apex. We tried giving up a corner to clearly have full thrust from the transmission on exit. Lots of messing around with ways to "compensate" for the transmission not doing what we thought it should do. Slower, Faster, Gentle, Hard. The instructors said I was driving the car well but they could hear the trouble I was having in the corners

Here's the most startling discovery.

I was rolling on throttle smoothly, but I eventually "floored it" to get maximum accelleration.

In rolling on throttle smoothly to the floor, I was pushing it past the kick down detent, which is what produced all the weird behaviors. Holding the throttle pedal "at the detent" (just at the pressure point) produces much smoother power delivery, and more power.

Once we figured this out -- Yikes, What a Machine!

The transmission acts as a CVT, it does not adjust as it did at "full throttle" position. RPM comes up to 5000 and holds there. Forward thrust is managed by the transmission (in SD). There was strong, smooth accelleration out of those linked corners.

We have a VERY capable little car, and it was FUN in the wet, after I figured out the throttle.

[Sejanus]

Quote:

Originally posted by johnewald

I was rolling on throttle smoothly, but I eventually "floored it" to get maximum accelleration.

In rolling on throttle smoothly to the floor, I was pushing it past the kick down detent, which is what produced all the weird behaviors. Holding the throttle pedal "at the detent" (just at the pressure point) produces much smoother power delivery, and more power.

I'm a little confused here. Is this with you shifting gears ala steptronic mode or in SD?