over reving

Please read the thread you have already started on this subject.

Depends on the car. There is a red line on the rev' counter. This should not be exceeded. Running near it for prolonged periods will greatly shorten the life of your engine.

I would suggest that the engine shuts off automatically to protect itself if the rpm gets into the red area.

Obviously you should not drive it at max rpm all the time :o)

I never tried, but do not think that the StepTronic gearbox would allow you to shift into a gear that would break the car. But why bother switching it manually - I think that it does a great job on it's own.

** Lars

I often use the manual override to take it down a gear or two when I am planning an overtake - no need to worry about if the kick down will happen as smoothly/timely as you want it - two taps of the lever then floor it!

if it's smart it won't let you downshift if the revs will spike past the redline... when that happens in a manual gearbox (usually 3rd to 2nd shift instead of 3rd to 4th) it's called the 'money shift' because you bend all your valves and lose a lot of money in about 0.2 seconds ! but in an auto it's not really possible, even the newer manual with auto-clutch boxes will not let you go past redline

4500rpm though is nothing, assuming you're past the break-in period (usually 1500km i think these days). you really should let it have a good rev now and then, don't be scared of watching the tach needle soar, the engine will love it and so will you !

Didn't you read the answers to your earlier thread on the same topic?

Steptronic is designed to be idiot proof.

Usually just switching to sport mode will make it drop a cog, and then you should be ready - in S the box will change up if you manage to red line it, whereas in a manually selected gear it will simply limit the rev's.

The lock up on my previous ZF 5 speed (not Steptronic) on an E34 525 was absolute. That's what I dislike about the 'nanny state' Steptronic - it doesn't allow you to start in a high gear in ice, etc. Or run the engine to the rev limiter. On a fun twisty road it's often the case where you'd do that with a manual in say second gear then back off slightly before the next bend - but the Steptronic changes up.

It doesn't shut off, but it starts not firing to limit the rev's.

Sure but if you're doing 60 and want to make an overtake, simply switching into S will drop to 4th but you'll still likely want to drop to 3rd to make the quickest pass. Not hard to remember to nudge the lever forward when the revs reach 5.5k or revs ;)

It doesn't change up if you're in manual mode?

The ZF version on UK cars does - it will change up or down if you exceed the rev limits at either end. Could be the GM version as fitted to some US BMWs may be different - but I doubt it.

Oh I hadn't noticed that - there's been a few times when I've been in manual mode on mine and noticed that it *hasn't* changed up automatically - it only changes down automatically when you come to a

*very* low speed.

Perhaps I just haven't abused it enough yet.

The previous 5 speed box was switchable. AFAIAA it only ever switches up in fifth in E[conomy]. If you change into S[port], then at anything below about a ton (and above 55mph) it will change down into 4th and won't go back up to fifth until you reach well in excess of 100mph* - whether it ever locks up in 5S I don't know, because I would normally revert to economy before I was likely to find out (nor indeed is it a good idea to drive that fast on public roads in the UK!).

Previous swtchable box also had snow mode (*) - this would start in third and worked rather well.

Prior to ZF5 switchable they had a four speed auto. Not bad, but a tendency to hunt between third, fourth and lock up on long winding bits.

• in a 740. I wonder if they set the lock up differently in the USA, as

55mph must be infuriating on the interstate...

You don't abuse a BMW engine by taking it to its rev limit. It's actually quite a sensible thing to do once in a while - after making sure it's properly warmed up.

In Steptronic mode it changes up at the same maximum speeds as in kickdown

- normal or sport.

In this mode, select a gear and it stayed in it regardless of speed.

4500 rpm is not even close to damaging the engine. I shift at 5000-6000 rpm all the time. Redline on your tachometer is supposed to show you what rpms are safe. Anything below redline is fine. That should be around 7500 rpm.

BTW - your steptronic will never down shift if the rpm it that will go to is going to be above redline. It's pretty smart that way...

Not the ones I've driven. It stayed in the gear that it was in until I moved the lever, except when you came to a crawl...

I nearly always use mine in auto and rarely red line it. Is there any point in having the manual sports option if it only does the same as the auto. I am relieved to know I cannot over rev the motor and maybe I would have used the sports/manual version more now but what is the point? pete

Have you noticed the red portion of the tachometer? If the needle goes into the red area, you screwed up. NEVER allow the needle to go into the red area.