[nick88]

Out of curiosity - why is it that on the bmw website with some models the acceleration times are significantly different between steptronic and manual?

for example: e90 325i 0-100km 7.0secs (man) 7.7secs (step)
323i 0-100km 7.8secs (man) 8.7secs (step)

does this mean if an e90 325i steptronic was racing in sports mode or 'M' mode against a stick 325i, would it be almost a second slower?

[MFKN3]

It means a manual with clutch will be quicker than the auto. Also depends on the driver too. Then dual clutch sports auto is meant to be faster again than the manual

[Sherweeeny]

Originally Posted by nick88

does this mean if an e90 325i steptronic was racing in sports mode or 'M' mode against a stick 325i, would it be almost a second slower?

yes

[GOLFFRR]

the determining factor is always the driver.

[Sherweeeny]

Originally Posted by GOLFFRR

the determining factor is always the driver.

well one of the drivers can wait 5 seconds after the lights gone green, and then begin the race. of course drivers will always be the determining factor, but i think here we are talking the technicalities of the cars, all things equal, drivers included.

[John_01]

I think the difference in 0-100 times, would mostly be due to the faster launch that is possible with a conventional clutch. Maybe thats not a huge advantage in daily driving, unless you absolutely must out-drag someone at the lights.

In normal driving the AT has a disadvantage because it can't anticipate when the driver is going to accelerate. There is always a finite delay for a conventional AT to shift down by one gear. Personally I prefer a conventional MT because I don't like to wait. With a dual clutch auto transmission (DCT) the changes are potentially faster, but I don't know how well it can anticipate whether the next gear is a downshift of an upshift. The DCT obviously works very well in a 0-100 sprint.

[nick88]

Thanks heaps guys for taking the time to explain it - it makes much more sense now

Cheers!

[JamieA]

IMHO the time difference would depend on the skill of the manual driver (swiftness of gear changes, proper timing for the torque characteristics of the engine etc) as well as the mechanical sympathy of the driver. You can get good outright times from a manual, but not really drive it for longevity of the clutch...

My observation is also the gap between MT and AT also seems to relate to the amount of toque the engine can offer. The more torque the more to offset the torque losses in the auto transmission, and the smaller the gap seems to be... well just from reading brochures anyway Would love to hear from anyone more technical than me on this.