Dynamic Driving switch revisited

[Asbjorn]

Let's use this thread to improve our understanding of the Dynamic Driving selector and DTC/DSC=off and make a table that is more accurate than the one we got from BMW.

I will keep updating the table in post #1 based on your inputs!

Here is why I feel there is a need to make an improved table. Last night when I was out burning some rubber I found a couple of interesting things

• The power steering with DSC off is not the same as in normal mode. It actually feels as heavy as in sport+. This is not what the table from BMW says.
  
• DCT S mode (pulling the the gearshifter to the left) offers the hardest shifting speeds. There is no manual mode that matches the S-mode in sport/sport+ in terms of shifting speed. It also shifts around 500rpm higher than the D-mode no matter which program is selected (normal/sport/sport+). This is not what the table from BMW says.
  
• And btw: The DCT can downshift directly from M7 to M2! Sometimes pressing down 5 times on the shifters just takes too long time. So here is how to avoid it: While at, say, 80kmh / 50 mph in M7 and arriving at the braking point, you quickly press down the kick-down switch with the gas pedal, let off immediately and start braking. The engine goes WROOM as it rev matches into M2.

That means the table from the training material from BMW to its dealers explaining the differences between the new and old Z4 contains several inaccuracies. Here is the original table.



And here is the updated version which includes the above observations and those of Memphis1 as well.



I don't have the adaptive suspension so someone else needs to verify that part of the table. Is there a difference between sport and sport+, and how about between normal and DSC off (long press)?

[nicknaz]

This is going to be a perfect example random internet speculation....

FWIW, my speculation-seat of pants-belief is

-- the shifting is similar enough between DS and M gearbox modes I don't notice
-- sport and sport+ suspension is same
-- amount of slip angle allowed in sport+ and DTC mode is same

oddly enough this is consistent with the training materials table you posted

EDIT: the only other thing I want to add is that I think the concept of the "drive mode selector" is dumb and I think my sports car should be "full attack" all the time without a reminder from me every time I start it

[Asbjorn]

Originally Posted by nicknaz

-- the shifting is similar enough between DS and M gearbox modes I don't notice

The biggest difference between DS and M is found in sport/sport+ mode, and NOT in normal mode. The S mode in sport+ will make the whole car jump on each gear change. The M mode wont, ever. On WOT S mode will create wheel spin where the M mode doesn't. Try and compare

M-mode (no DSC intervening)

http://v.youku.com/v_show/id_XMzgxNjc2NzM2.html

S-mode (DSC blinks going from 2nd to 3rd)

http://v.youku.com/v_show/id_XMzgxNjc1Njc2.html

Password: "BMW"

But I think it is easy to feel while driving normally as well. I will be very surprised if you don't experience the same.

Originally Posted by nicknaz

-- amount of slip angle allowed in sport+ and DTC mode is same

OK, I will try again... maybe the different accelerator pedal characteristics are still fooling me.

Originally Posted by nicknaz

-- sport and sport+ suspension is same

What about DSC off? (I dont have the adaptive suspension)

[Asbjorn]

Originally Posted by Asbjorn

Originally Posted by nicknaz
-- amount of slip angle allowed in sport+ and DTC mode is same

OK, I will try again... maybe the different accelerator pedal characteristics are still fooling me.

OK, I just tried again, and it seems you are correct. It is possible to get the tail out in DTC mode, but it takes a bit more effort compared to sport+

Thanks alot for the input! I am updating the table...

[nicknaz]

I don't know Ashjorn.. I believe the BMW training material chart in this case. I haven't experienced anything that makes me think there is an error.

To answer your question, with DSC off the suspension feels like in comfort mode.

[zEdP]

Originally Posted by nicknaz

FWIW, my speculation-seat of pants-belief is

-- sport and sport+ suspension is same

My pants do believe that there is a difference between sport and sport+ suspension shock absorber damping.
According BMW there should be a difference:

[Asbjorn]

Originally Posted by nicknaz

I don't know Asbjorn..

OK, here is the most simple test to get us started... drive from side to side at a constant speed in normal. Notice how "light/heavy" the steering feels. Then, while still doing that, hold down the DSC button until it turns DSC off (takes a few secs).

Now, does the steering feel the same in your car?

I would say that you can feel just from the steering when the DSC was turned off.

[Asbjorn]

Originally Posted by zEdP

My pants do believe that there is a difference between sport and sport+ suspension shock absorber damping.
According BMW there should be a difference:

Nice catch Ed

According to this the difference between sport and sport+ should be easier to feel than normal vs sport?

In any case, it looks a bit like marketing bs, because the system can "only" attenuate the dampers, not the springs after all...

[zEdP]

Originally Posted by Asbjorn

Nice catch Ed

According to this the difference between sport and sport+ should be easier to feel than normal vs sport?

In any case, it looks a bit like marketing bs, because the system can "only" attenuate the dampers, not the springs after all...

Yes this is just a marketing picture to illustrate the difference with the 'hard' E85 and flexible E89 without quantifying them.

[itsfred]

On a related, but slightly different note, I just took a test drive in a 2011 35is and the shift buttons (quasi-paddles) were inoperative in normal mode. The salesman claimed they only work in sport, sport+, or manual mode. In my prior experience with Audis and Porsches, the paddles are always active and override the the automatic shift programming for maybe 30 seconds before reverting to auto mode. Is the salesman right? Is this a setting than can be reconfigured in the Z by recoding the cpu? Thanks for your feedback...

[Asbjorn]

Originally Posted by itsfred

On a related, but slightly different note, I just took a test drive in a 2011 35is and the shift buttons (quasi-paddles) were inoperative in normal mode. The salesman claimed they only work in sport, sport+, or manual mode. In my prior experience with Audis and Porsches, the paddles are always active and override the the automatic shift programming for maybe 30 seconds before reverting to auto mode. Is the salesman right? Is this a setting than can be reconfigured in the Z by recoding the cpu? Thanks for your feedback...

Welcome to the forum first of all.

I have the "old" paddles where both can be used to both down- and upshift. With the gear selector in D they work like you experienced with Audis and Porsches before. If you pull the gear selector to the left you first get S mode and then permanent M mode if you decide to up or downshift manually. So my paddles are always operative except in R and N. Perhaps the functionality was changed with the new pull-pull paddles or just in the is...

[nicknaz]

@itsfred pressing the shifter button should change the gear.

Time to find another example of the car and a different sales person.

My inclination is that the sales person is trying to sell you a defective car with a double helping of BS

[e85sbm]

[QUOTE=Asbjorn]
[*]And btw: The DCT can downshift directly from M7 to M2! Sometimes pressing down 5 times on the shifters just takes too long time. So here is how to avoid it: While at, say, 80kmh / 50 mph in M7 and arriving at the braking point, you quickly press down the kick-down switch with the gas pedal, let off immediately and start braking. The engine goes WROOM as it rev matches into M2. [/QUOTE=Asbjorn]

can you explain this better....what is the gas pedal kickdown switch? Do you need to use the paddles, or gear lever to advise the car you want to downshift?

[jparnes1]

[QUOTE=e85sbm;14016357]

Originally Posted by Asbjorn

can you explain this better....what is the gas pedal kickdown switch? Do you need to use the paddles, or gear lever to advise the car you want to downshift?

When you push the gas pedal, just before it hits the floor you will feel a bump. go past the bump and the transmission downshifts usually 2 or 3 gears. Lazy man's way to haul ass.

[nicknaz]

Originally Posted by Asbjorn

OK, here is the most simple test to get us started... drive from side to side at a constant speed in normal. Notice how "light/heavy" the steering feels. Then, while still doing that, hold down the DSC button until it turns DSC off (takes a few secs).

Now, does the steering feel the same in your car?

I would say that you can feel just from the steering when the DSC was turned off.

There is definitely a brief change of effort in the steering wheel when I turn off the dsc. It is almost like the steering wheel program resets itself when I turn off the dsc. I am not sure I would say it goes to sport+ effort level. It seems pretty similar to comfort but admitted it is a very subtle change and I tried this going around a parking garage at low speed.

The suspension definitely goes to comfort damping when I go to dtc mode or dsc off mode.

One interesting thing i noticed is that I think in comfort the steering wheel subtly helps to keep the car in a straight line. For example, if i am going straight on the highway, takes more effort for me to make the car change direction away from a straight line vs if I am in sport or sport+ mode.

Kind of a useful feature and I have started to drive in comfort when I am slugging through highway miles in a straight line using cruise control.

[nicknaz]

Originally Posted by zEdP

My pants do believe that there is a difference between sport and sport+ suspension shock absorber damping.
According BMW there should be a difference:

I wish I could find that same table for the f30. I put in an order for a 335 recently to be my wife's new daily driver and I decided to go with the passive m sport suspension ("option 704") instead of getting the adaptive suspension, in part because the adaptive suspension is bundled with the variable steering ratio (*shudder*)

[Asbjorn]

Originally Posted by nicknaz

There is definitely a brief change of effort in the steering wheel when I turn off the dsc. It is almost like the steering wheel program resets itself when I turn off the dsc. I am not sure I would say it goes to sport+ effort level. It seems pretty similar to comfort but admitted it is a very subtle change and I tried this going around a parking garage at low speed.

The suspension definitely goes to comfort damping when I go to dtc mode or dsc off mode.

One interesting thing i noticed is that I think in comfort the steering wheel subtly helps to keep the car in a straight line. For example, if i am going straight on the highway, takes more effort for me to make the car change direction away from a straight line vs if I am in sport or sport+ mode.

Kind of a useful feature and I have started to drive in comfort when I am slugging through highway miles in a straight line using cruise control.

Thanks a lot for describing this. I think I recall experiencing what you describe about the sports steering. Auto-centering and auto-correcting on over-steer are both functions made possible only with electric power steering. They only work because the computer decides so, and hence might also improve/weaken between the modes.

Alright forum, who else here has a butt-dyne and wants to confirm any of the above experiences? This is important you know

[nicknaz]

I wouldn't say the car is "auto correcting" the steering because the steering angle doesn't change but the effort level to turn the steering is changed

i.e. I detect slightly more effort to move the steering away from dead center when in comfort vs. sport or sport+

[Asbjorn]

Originally Posted by nicknaz

I wouldn't say the car is "auto correcting" the steering because the steering angle doesn't change but the effort level to turn the steering is changed

i.e. I detect slightly more effort to move the steering away from dead center when in comfort vs. sport or sport+

There are at least two "special" features of the electric steering in a Z4.

1) Auto-center. You turn the wheel to make a turn and let go of the steering wheel while still driving. The steering wheel rotates back to center by itself. Steering racks which are not power assisted or have the simple hydraulic system would do the same, but not to the same extend (more dependent on G-forces or feedback from outside).

2) Auto-correct on over-steer. When the car over-steers, the electric steering helps you to counter-steer as quickly as possible. Steering racks which are not power assisted or have the simple hydraulic system would do the same, but not to the same extend.

I know we were not talking about auto-correct on over-steer here. And I don't think the steering auto-corrects anything during any other driving situation, not even while under-steering.

Anyway, I think I already agreed with what you said, and I can related to in another way as well. In normal mode the car will continue straight even if there are some irregularities in the road. It makes driving very comfortable as it filters out imperfections in the road surface and continues straight if the steering wheel is pointed in that direction. In sport irregularities are not filtered to the same extend, and the car will change direction and send feedback through the steering wheel more naturally according to the road surface. It sort of looses its preference for sitting comfortably in dead-center.