Questions re: Acceleration and Gear Changes

4877 Views 5 Replies 3 Participants Last post by rnlabas, Jun 23, 2015

ivorbiggun

Discussion Starter · Jun 19, 2015

I have noticed that when I am accelerating rapidly from a stand still or from a constant speed, in either regular or sport mode, but NOT with the pedal all the way to the floor, the engine stays in first gear and does not authomatically shift up to the next gear and I have to ease up on the throttle so the engine doesn't red line.
My questions are:

1. Does this have something to do with the kick-down switch is being engaged or not being engaged, even though I am maybe only pusing the accelerator pedal 3/4 of the way down.

2. Is there somethign wrong with my car?

3. What would be the normal behaviour of the engine if, for example, you "floored it" all the way from a standstill in standard automatic mode (or even sport mode)? Would the engine ultimately just redline all the way, or should there be a safetly mechanish that change up to a higher gears prior to or just after redlining?

I'm a little concerned because I never noticed this behaviour with my 2010 Golf. I seem to remember that the engine would change up a gear even if you gunned it.

Help! Is my car broken?

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rnlabas

· #2 · Jun 19, 2015

As long as you have the throttle pressed - over half way, the engine will accelerate up to redline. There is NO safety mechanism other than the fuel cutoff at redline - the rev limiter. Under "normal" acceleration - usually less than 50% throttle, the engine will "remember" your driving pattern including throttle lift offs to encourage a shift up, or will use its own shift up program at say 3-5500 RPM. But once beyond 50% throttle when "accelerating rapidly" as you state, you can count on redline shifts unless or until YOU lift off...

And if "floored" you can ALWAYS count on redline shifts - yatta hey, what do you really want when you floor it?

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ivorbiggun

Discussion Starter · #3 · Jun 20, 2015

Thanks Roger!

That's very good to know: >50% on the throttle and no auto gear change.

So if I have the throttle pressed more than half way or floored, and the tachometer needle goes into the red, the car will shift up to the next gear when the needles reach all the way to the far right of the tachometer or will it shift when the needles are halfway in the red? I must say that I get scared that I will blow the engine. Not that I drive like that in an unsafe manner on city streets, but there are the times where i want to enter the highway in a "spirited" fashion..

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rnlabas

· #4 · Jun 20, 2015

ivorbiggun said:
Thanks Roger!

That's very good to know: >50% on the throttle and no auto gear change.

So if I have the throttle pressed more than half way or floored, and the tachometer needle goes into the red, the car will shift up to the next gear when the needles reach all the way to the far right of the tachometer or will it shift when the needles are halfway in the red? I must say that I get scared that I will blow the engine. Not that I drive like that in an unsafe manner on city streets, but there are the times where i want to enter the highway in a "spirited" fashion..

Don't worry about ANY spirited fashions - unless the engine is too cold - that is not fully warmed up; you won't blow the engine this way (warm spirited fashions - I like that). The car will shift at redline (and it will be more accurate than the guage) which may look like it's a bit past that on the gauge. If you try to rev beyond that, a computer will interrupt the fuel to the fuel injectors and it will sound (and feel) like a power losing sputtering - an effective rev limiter in any case.

The only way to really over-rev these engines is to force a downshift from a higher speed than the car would upshift from - which you might do in an emergency braking case or loss of mind - in which case you could over-rev it and that might be catastrophic -

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Quatto

· #5 · Jun 23, 2015

Running an engine like that when cold and doing that a lot over time I think can lead to an engine that eventually starts to burn oil.

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rnlabas

· #6 · Jun 23, 2015

Quatto said:
Running an engine like that when cold and doing that a lot over time I think can lead to an engine that eventually starts to burn oil.

Good point about a cold engine - as I noted above - but as far as redline shifts as often as you want - not to worry. These engines are run at redline (or very near) for hours every day and many days, often - in Germany. In fact running them too slow IS an issue for the US side of things. These engines are designed to run - not just at 2-3K rpm like we normally run them...

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