[max_m5]

Test from Autozeitung.

http://www.bmw.com/generic/de/de/products/automobiles/pdf/az24_bmw_smg.pdf

It says: The SMGIII is 10 times faster than the best manual shifters!!!

 

[jos]

Test from Autozeitung.

http://www.bmw.com/generic/de/de/products/automobiles/pdf/az24_bmw_smg.pdf

It says: The SMGIII is 10 times faster than the best manual shifters!!!

Isn't this the reason why they made it, to make the shifting times quicker?

 

[EBMCS03]

So it shifts that fast but I always wonder what about engine speed dropping time when you upshift. You know what I mean... I dont think the engine can lose ~1.5K RPMS as fast as the SMG can shift, so it surely is using the clutch to bring the engine speed down for the next gear to match the wheel speed. Say upshifting from first to second at 9K RPM and second gear it will be what? about ~7.5K RPM?

 

[Wolverine]

Test from Autozeitung.

http://www.bmw.com/generic/de/de/products/automobiles/pdf/az24_bmw_smg.pdf

It says: The SMGIII is 10 times faster than the best manual shifters!!!

We must be losing something in the translation here.

The SMGII is barely quicker than the best manual shifters (ref comparison article M3 6sp vs M3 SMG). So how does a 20% improvement over the SMG II make it '10 times faster'?

 

[thebishman]

We must be losing something in the translation here.

The SMGII is barely quicker than the best manual shifters (ref comparison article M3 6sp vs M3 SMG). So how does a 20% improvement over the SMG II make it '10 times faster'?

Perhaps since the SMG III shifts in 65 ms and even a very experienced 'human' manual gearbox shift, (even a straightforward one such as 3rd to 4th), would take about 650 ms, (slightly > than 1/2 second)?
Just a thought.

 

[Enigma]

We must be losing something in the translation here.

The SMGII is barely quicker than the best manual shifters (ref comparison article M3 6sp vs M3 SMG). So how does a 20% improvement over the SMG II make it '10 times faster'?

A few things to keep in mind.

The M5 isn't designed for a human to do the shifting unlike the SMG II which shared parts with the non SMG version.

so

The gearbox, clutch, and flywheel can be designed without the compromise needed to allow for ease of use. We know the gearbox has an abnormal pattern. The clutch is a twin plate. I would assume the flywheel is much ligher than normal.

This means

The lightweight flywheel and clutch stores far less energy. This means the car accelerates better in gear since less of the energy produced by the engine is stored in the flywheel. Also since its this energy that gets disapated in the form of a thump when the next gear engages the jolt should be far less with SMG III. Also since the flywheel is lighter the engine can build revs faster for a downshift.

 

[Wolverine]

A few things to keep in mind.

The M5 isn't designed for a human to do the shifting unlike the SMG II which shared parts with the non SMG version.

so

The gearbox, clutch, and flywheel can be designed without the compromise needed to allow for ease of use. We know the gearbox has an abnormal pattern. The clutch is a twin plate. I would assume the flywheel is much ligher than normal.

This means

The lightweight flywheel and clutch stores far less energy. This means the car accelerates better in gear since less of the energy produced by the engine is stored in the flywheel. Also since its this energy that gets disapated in the form of a thump when the next gear engages the jolt should be far less with SMG III. Also since the flywheel is lighter the engine can build revs faster for a downshift.

I'll state the problem another, way. The SMG III has a minimum shift time of 65 milliseconds. The SMG II was 80 milliseconds, just a hair faster than a pro driver. If the SMG III was 'ten times faster' than a human, then that would mean a pro takes 650 milliseconds to shift. That's not even close, so we're either talking about a translation problem, or an overly enthusiastic reviewer.

The limiting factor in SMG shift speed isn't the inertia of the flywheel, it's more likely the synchros. I would imagine the 65 ms shifts are getting close to the limits of the synchros in terms of causing unacceptable wear.