O/d On Auto Tranny

[The Don]

I think Newbies question is very relevent thought it might not necessarily have anything to do with the transmission at all,

The M Switch basically changes the engine mapping and increases the cut off point and really pushes the BHP on the 5 Litre engine from 300 odd BHP to 500 odd BHP,

In the verossa, it could be something similar or it could be a way where the engine mapping is changed to suite each condition,

For example a sports mode may change the engine mapping to increase the BHP of the engine (and thus consume more fuel which is why it is presented as an option)

The snow mode possibly maximizes the torque of the engine to suite snowy conditions, because with my very limited experiences driving in snow, its not the brightest idea to aim for the best 0-60 timingst on snow, and slow gradual acceloration results in better grip and better car control in snowy conditions,

I wonder whether your car has traction control which is what the snow button activated, don't really know enough about the car, but then again I guess traction control would always be on, on a non sports car.

I think the OD can also be explained in the same way I first learned about torque convertors many moons ago in a local magazine (in Sri Lanka), Consider 2 fans facing each other, and one fan is represntitive of the rotation of the engine and power being transferred into the transmission box, and the other fan the power being transferred to the wheels to provide momentum.

I am sure i am not knowledgable enough to remember the terms for each of the internal components of an torque convertor.

If you power up one fan (the engine), you would see the other fan also start to move because of the air (the AT fluid) flowing towards the second fan, and first the second fan will rotate slower than the first fan but slowly but surely both fans will start rotating at the same speed. This is the system at its maximum efficiency.

On overdrive mode the second fan would spin even faster than the first fan, and how the transmission achieves this is better explained in those articles I referred you to.

So essentially you gain better engine efficiency and may loose out on the 0-60 times or on acceloration.

How it feels in different implementations is possibly as tuk tuk explained. I am sorry I have only driven 2 auto cars in my entire life and hated them both

Atleast thats the best I understand the concept,

The Don

[isurujosh]

Correct me if I am wrong shouldn’t the gears shift when maximum output is achieved at the right RPM. If the gears shift before wouldn’t it be a waste of something or the other. If the RPM is too high then it still would be a waste as the car would not be moving any faster.

This is where I got the idea that when the power button is on the gears will wait tile the maximum useful RPM is reached before it changes.

When the Power button is off the gears would shift faster at lower RPM there by not put any strain on the motor and conserve fuel.......

Isuru what does the M button on the BMW M do ?

Come onnn experts.....I know you guys are out there....give me your take on the matter........

If it seems like I am H/J thread I apologize and feel free to have the Mods delete this.

hey i guess there was some confision! ... i meant the difference between "taller gears and shorter gears" not the shifting points... yes u r absolutely right! the change should occur at a peak for performance gains!

i guess the M5 changes the gear ratios to a more ferocious setting upon pressing "M" button(plz correct me if i am wrong ... i am no expert ... i am also an eager student)

The M Switch basically changes the engine mapping and increases the cut off point and really pushes the BHP on the 5 Litre engine from 300 odd BHP to 500 odd BHP,

or is it 400 to 500

[The Don]

Hi Isuru,

Yeps I think you are correct

Against the stopwatch, the 500-horsepower M5 is in the same league as the Audi RS6 and the Mercedes-Benz E55 AMG, because the makers of all three quote a 0-to-62-mph time of 4.7 seconds, and all three bump up against the limiter at 155 mph. But the BMW is different, because it involves you and feels as if it was built by people with passion. Putting the M5 through its paces is a spine-tingling and pupil-widening experience. This is a high-performance five-seater that can be fine-tuned to meet individual preferences and driving styles. The new M5 invites you to calibrate the engine, transmission, steering, traction control, and damper characteristics. The 5.0-liter V-10 offers three performance programs: P400, P500, and P500 S, denoting 400, 500, and 500 horsepower in sync with an ultrasharp throttle action. The transmission wants to be told whether to operate in sequential or automatic mode and at which shift speed. The Servotronic steering can be quick or very quick. Stability control can be fully active at all times, set to allow a certain amount of tire slip, or switched off altogether. The EDC (electronic damping control) button chooses among three levels of suspension tautness: comfortable, normal, and sporty.

The only bad news is that you access the systems via iDrive, the onboard mouse that will turn into a poisoned rat following a wrong twist or push. Although most options are individually accessible via buttons in the center console, P500S, Servotronic S, and dynamic traction control require deep dives into various submenus. Alternatively, you can store a feature on the star button in the multifunctional steering wheel. Right above it is the even more significant M button. Push it, and the power output automatically jumps to 500 horsepower, the skid control system (DSC) switches to M Dynamic Mode (MDM), EDC stiffens up the dampers, and Drivelogic sets your preferred shift speed. Then you can forget all the confusing secondary controls and concentrate on what matters: driving the socks off this truly awesome fourth-generation M5.

The Don

[sharkster]

newbi guess who has a power and snow button just like you ...i've never used them though...how bizarre...i've used the car for 4 years and i've never played with it...hmmm

[noaim]

newbi guess who has a power and snow button just like you ...i've never used them though...how bizarre...i've used the car for 4 years and i've never played with it...hmmm

the premio's got the snow button too... lol