over reving

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Must be a different spec to mine. It definitely changes up at the red line, and changes down at about 1000 rpm.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Dave Plowman (News) wrote:

Perhaps it does upshift at redline. It was not my car so I did not test it at that high an rpm. But who cares, no sane person waits until redline to shift up. You are past peak horsepower so there really is no point...
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Peak horsepower matters not a jot, really.;-) And my 528 doesn't run out of puff at the maximum auto change up point. What you ideally need is to get near peak torque on the next higher gear. Hence the demise of 2 speed autos...
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wrote:

Not sure about the 2.8, but the 220hp 3.0 litre develops maximum torque at 3,500. So with the exception of the 1~2 shift, upshifts should be well below the 6,500 redline (ca. 4,500~5,000) to hit the torque peak in the next gear in a 6 speed manual.
Tom K.
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"Tom K." wrote:

Excellent example, Tom, of why shifting for peak torque in the next gear is usually shifting too early when you want maximum acceleration.
Frank
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"Dave Plowman (News)" wrote:

Not necessarily. Acceleration is proportional to horsepower, not torque (I'll show you from F=ma, if you want) so what you want to do is maintain the highest value of hp that you can. Pretty sure this means that you want to go far enough past the peak that when you shift to the next gear, and drop down on the other side of the peak, you haven't gone significantly lower in hp than where you just were in the previous gear.
If that point matches peak torque, it's just a coincidence.
Frank
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On Tue, 07 Mar 2006 19:31:11 +0000 (GMT), "Dave Plowman (News)"

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
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Ok I tested this at the weekend. Switched into manual mode, popped it into 2nd and took it up to 6000rpm - no automatic upchange. I didn't feel inclined ot keep it at those revs for any longer but, certainly on mine, selecting a gear manually keeps it in that gear *unless8 the speed drops to a crawl. If it had changed up automatically at over 6000 revs it would be academic anyway - therefore I think that, with reference to your previous statement:
"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."
In my experience you can do exactly as you describe above without the system automatically changing up.
cheers
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Have you observed the RPM at the gearbox changes up when using kickdown? That is exactly the same maximum as it will when using the Steptronic selection. That you choose to rely on some arbitrary figure on your rev counter for the sake of your argument makes no difference.

You've not been trying hard enough. ;-)
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OK I'll go and do some more testing and report back :)
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jeremy
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OK I've tried a bit harder now.
You are completely correct.
It will force a change up from 1st to 2nd in manual mode when you hit approx 6300 rpm (inside the red zone).
I still reckon your remarks regarding holding it in gear on a fun twisty road were misplaced though - after all you're not actually going to want to rev it ~6300 and hold it there - and it would be quite a coincidence if the maximumm speed you wanted to do in a particular gear would correspond to say ~6400?
It was fun finding all this out though ;)
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That's no surprise. ;-)

Yup. On my car the auto transmission gets well into the red zone on kickdown. I'd not expect any different since it's not a brick wall sort of thing. The engine ECU does that.

No. On a manual you 'feel' when the engine is reaching maximum revs since all go over peak power. So you back off slightly. The fooking Steptronic changes up so you end up without maximum power to drift through a corner. When having a play on a deserted road. Basically Steptronic is a waste of time and most who have it never bother with it. The sports auto mode does as well.

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Interesting. Mine only allows a second gear start. Nor can you change up below its limits - although the dash indicator will show the higher gear you've attempted to select before reverting to the actual one.
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London SW 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...
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In this mode, select a gear and it stayed in it regardless of speed.
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Didn't you read the answers to your earlier thread on the same topic?
Steptronic is designed to be idiot proof.
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cruso wrote:

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...
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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.

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In normal auto mode, kickdown will take you into the red area.
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wrote:

Then the driver is doing something wrong. If a downshift carries the motor into Red Line, the downshift was poorly timed. Period.
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