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  #1  
Old 01-24-2015, 02:03 PM
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Angry Retarded Transmission

Is it just me or does the mapping in transmission seem like it belongs in the V6 gasser?

Example: Adaptive Cruise set at 70mph. Vehicle ahead going 65mph. Vehicle ahead moves over and the transmission drops to 5th. 5th!!

Why in god's name would it drop to 5th? At 65mph in 8th gear there is plenty of torque at that RPM.

Every time this scenario comes up, I find myself engaging the manual shifting just to avoid dropping down to 5th and engine near redline. In 8th gear, it still pulls to 70 quite briskly.

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Old 01-24-2015, 07:31 PM
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Re: Retarded Transmission

All I can say is that I've never once had shifting like that on my V6 gas. I've actually been pleasantly surprised to see how well it holds a higher gear where I'd expect it to downshift.

How hard is your ACC kicking the throttle down when it senses that it can resume it's previously set speed?
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Old 01-24-2015, 10:10 PM
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Re: Retarded Transmission

I mean, we're talking about 5mph difference. It seems like it must "floor it". If I were driving without ACC I could push the pedal down 10% more and get the acceleration needed to briskly get a 5mph increase all without downshifting.
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Old 01-24-2015, 10:13 PM
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Re: Retarded Transmission

That's what I was wondering. The ACC would have to be really romping down on the throttle to get a 3 gear downshift like that. That's not good.
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Old 01-24-2015, 10:18 PM
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Re: Retarded Transmission

I guess I should amend my title to "Retarded ACC".

I wonder still if anyone else is experiencing this.
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Old 01-24-2015, 11:44 PM
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I've definitely noticed this as well, and it's the reason I switch to manual shift mode when ACC is on... to lock it in 8th, as you mentioned.

However, I most frequently encounter this when changing lanes when I'm blocked in the right lane and there is another vehicle ahead in the left. What seems to be the case is that ACC sees the open road between the vehicles, tries to floor it during the lane change, then has to (literally) apply the brakes a second or two later when it realizes that it would rear end the left lane vehicle otherwise. This can be mitigated by sharply changing lanes so that the sensor "sees" the other vehicle more quickly. Or, you know, limiting the aggressive acceleration via manual shift mode.

It's somewhat ironic that FCW is such a nanny that it freaks out and brakes in circumstances where there's no risk, but ACC drives like a 16 year old boy hopped up on testosterone and Toxoplasma.
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Old 01-25-2015, 12:30 AM
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Re: Retarded Transmission

Quote:
Originally Posted by
It's somewhat ironic that FCW is such a nanny that it freaks out and brakes in circumstances where there's no risk, but ACC drives like a 16 year old boy hopped up on testosterone and [I
Toxoplasma[/I].
Amen, brother...

I only know my antilock brake system works because of the FCW.
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Old 01-25-2015, 12:30 AM
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Re: Retarded Transmission

I've noticed exactly this as well. ACC seems to ignore sport mode and shift to whatever gear it wants; ACC@80mph it likes to drop into 6th if I'm following a car at 70 and change lanes.

shifting is otherwise quick and smooth so I've stopped stressing about it unless the difference is more than 10mph or so and then it goes really nuts. I just cancel it and resume after accelerating normally in that case.

its pretty fun to see what it does if you leave it set at 70+ after ACC/FCW brings you to a near-stop for heavy traffic/road hazard
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Old 01-25-2015, 12:40 AM
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I don't mind the hard acceleration so much as the fact that it immediately applies the brakes to slow down after gunning it. Keeping it in 8th moderates the acceleration, which reduces the subsequent deceleration required. If ACC is being especially obtuse I will temporarily cancel it.

It's strange: I know for a fact that the sensor can see the other vehicle, because FCW freaks out about vehicles that are at even more oblique angles than this. ACC just ignores that data.
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Old 01-26-2015, 01:46 PM
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Re: Retarded Transmission

I've experienced this as well. I've found that if the difference between your current speed and the ACC set speed is low (<5 mph) it doesn't seem to floor it.

What I do if I'm passing is to preempt the ACC by stepping on the gas myself before I start changing lanes. This puts it in "driver override" mode and I can accelerate at whatever rate I want. I guess this may not work depending on how close you are to the car ahead of you and how sensitive your FCW is set (I have mine on "close" or "low" or whatever) because it might kick in.

Good suggestion on the manual gear selection, I hadn't thought of that.
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Old 01-26-2015, 01:51 PM
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Re: Retarded Transmission

Quote:
Originally Posted by Roadkill View Post
It's strange: I know for a fact that the sensor can see the other vehicle, because FCW freaks out about vehicles that are at even more oblique angles than this. ACC just ignores that data.
That kind of behavior has tempted me to turn off FCW entirely. There have been several times when there's a car slowing way down to turn into a driveway or something and I go around it at my original speed, the FCW kicks in and slams on the brakes for me. It's disconcerting because if a car was following me closely there's no way they'd expect me to slam on the brakes like that and could rear-end me. I have to learn to start to steer around the other car a lot earlier than I am used to doing.
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Old 01-26-2015, 01:59 PM
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Re: Retarded Transmission

Quote:
Originally Posted by Rumline View Post
I have to learn to start to steer around the other car a lot earlier than I am used to doing.
Haha, yes, I do that too! Weaving halfway into the next lane until the "threat" is cleared (provided this maneuver can be done safely). On a non-FCW vehicle I would just stay in the same lane and coast, easily retaining enough space to comfortably stop even if the other driver braked abruptly.

Safety features that cause me to appear like an inattentive or impaired driver: ironic?
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