BigGrey

Hi,

It seems to me that the DS upshift mode is not optimized for acceleration for my 525d.

For acceleration, it should change gear at 4000 rpm instead of going until the redline, no? Sometimes i feel like saying "hey, come on, this is a diesel shift up!"

That is perfect for the petrol engines, but for diesels, it feels like they loose performance when at top of rpm range.

Do you have the same feeling in 530d and 535d Steptronic?

colejl

In the 530d it's the same... That's why I stick to D or M.

The 535d doesn't lose performance at the top of the rpm range (2nd turbo kicks in) so it probably works great...

BetterMakeWay

1st of all i don't really notice or i'm just too hard to satisfy, the difference between DS and D (regarding time needed for gearchange). Sure it is smth else but the actual gear changes are almost the same in time. Only a bit faster in DS. It should be alot faster and more agressive. But after all it is an automatic...

Regarding ur post i didn't drive the 530d steptronic but i can assure u it shouldn't change too far from the point when the turbo looses it's grunt (near 4000rpm). Going to the redline is not optimum and i guess some softwerer for single-turbo diesels is needed to correct that. If i were u i would take it to manual and shift up around 4000rpm. I know that because i also have a tdi passat wich as all single turbo diesels looses power after around 4000rpm. After that u rev the car pointless.

Regarding my own experience with my car i can tell that it keeps pushing and pushing even at 4800 rpm. It is amaizing how that big turbo does the work. So in the 535d it's nto the same. From idle to redline this car pushes like there is no end. Even after 200km/h it's still like a cock going onwards till it reaches aroun 250-255 where smth terrbile happens . I'm saying that many petrol cars with around 200-250 hp like golf 5 gti or seat leon cupra 225bhp or whatever, after 200km/h they loose vigor and grunt, the needle snails it's way to 250 but in this OMG i'm still impressed, the needle doesn't show sign of fatigue. It keeps going and going with those redline upshifts and kinda jerky and slow gear changes.

znod

To figure out if your car is losing torque by shifting at redline you would need to look at its torque curve to figure out if you would be better off in a higher gear. If road torque would drop if your car shifts to a higher gear earlier than it does now, then you are better off with it not shifting earlier even if engine torque drops by, for example, going to redline.

streak

YES, same here.
Under hard acceleration (D or DS) I find the revs go way beyond the useable range and then drop to low after the gear change.

Some time ago, when I fitted the ACS box to my car the tech. told me how clever the BMW Auto box is because it monitors boost and makes sure that gear changes are optimum. I very much doubt this.

Streak

BetterMakeWay

I really think the auto box is one of the most clerver part in the car. It detects uphills, downhills, has self teaching module that adapts after the driver...quite alot of impressive stuff. If it has the monitoring system for the boost...may be true. I don't know for sure. One thing is for certain:

And this regards more the 535d owners since it occurs more often or only on this engine. Other diesel owners may certify if this thing occurs: So it's like this, i'm accelerating a bit harder and the gearbox downshifts a gear, and then not being to agressive with the throttle (not at the floor), neddle goes obviously in higher rpm range, i continue to accelerate hard, car is moving faster but the rpm neddle stays almost put, like not revving to the redline if i don't weld my foot deep into the throttle. The car goes faster and faster but the rpm neddle doesn't seem to be very active (like at around 3000rpm-3500 rpm). I am in D mode though...If i barry my foot down the neddle moves normaly around the rev range to the red line but if not it kinda slouches although the car is accelerating.
I don't expect you to understand me, i jsut hope i made it as clear as possible.

streak

I have seen this in my 530D as well. The tech. explained it to me as
torque-converter lockup, a feature not a problem of the gearbox. As he said it can lock or unlock at any time.

I sometimes even notice a slight dip in revs before they continue to increase.

colejl

Indeed - this improves performance at the expense of economy...

Merv the Derv

I always thought that the gearbox held the gears for too long after 4,000 rpm on my 530d. The power just drops off after this point, however, its a different story with the 535d's second turbo as ColeJ rightly said earlier.

mixterk

In the 530d it's the same... That's why I stick to D or M.

The 535d doesn't lose performance at the top of the rpm range (2nd turbo kicks in) so it probably works great...
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535D pulls right across the rev range because of the progresive handover from turbo to turbo...love the wide power band, was going to get a 530i petrol (had a 330i and loved that) but once I experianced the shot in the back from the torque of the 535 i couldnt resist