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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Kickdown button anger



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      06-26-2009, 04:34 PM   #23
Terrance28
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Quote:
Originally Posted by who's ur daddy? View Post
On the track you don't want the car shifting mid-turn as that unsettles the handling balance.
Then be in the right gear for the turn the car will only kickdown if there is room in the rpms to drop down to safely.
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      06-26-2009, 06:59 PM   #24
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Quote:
Originally Posted by Terrance28 View Post
Then be in the right gear for the turn the car will only kickdown if there is room in the rpms to drop down to safely.
Not true, how does it know when to drop-down safely? Its not like it knows your in a tight turn and shifting down will upset the balance. The kickdown wouldn't be a big deal if you could disable it....for god's sake: when your in manumatic mode why the does it kick down..that makes no sense. With the gobs of torque, shifting down doesn't always make things quicker.
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      06-26-2009, 07:06 PM   #25
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Quote:
Originally Posted by 335lvr View Post
Not true, how does it know when to drop-down safely? Its not like it knows your in a tight turn and shifting down will upset the balance. The kickdown wouldn't be a big deal if you could disable it....for god's sake: when your in manumatic mode why the does it kick down..that makes no sense. With the gobs of torque, shifting down doesn't always make things quicker.
I think he meant if the engine still has some room to downshift without going over redline it will if you kickdown. If you're already in a low gear at high rpm and try to kickdown it won't downshift because that will over rev the engine.

I don't understand what the big deal is? Don't hammer your foot down and it won't kickdown. Just put enough pressure down to not trip the kickdown you still get 100% WOT without a downshift. I think kickdown was put there for safety reasons. If you have some noob driving in manumatic in too high of a gear and suddenly realizes he needs to accelerate quickly, kickdown will put him in the right gear.
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      06-26-2009, 07:23 PM   #26
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In a different thread, somebody explained the concept:
The button is a placebo and it does not help to remove it.

The throttle angel before the click is 90-95%, upon full throttle, which is when the button is pressed down, the ecu detects the 100% angels, shifts down and gives full power. (even a bit above standard turbo pressure if I understood well)

This seems to be different from a MT....
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      06-26-2009, 08:49 PM   #27
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Quote:
Originally Posted by 335lvr View Post
Not true, how does it know when to drop-down safely? Its not like it knows your in a tight turn and shifting down will upset the balance. The kickdown wouldn't be a big deal if you could disable it....for god's sake: when your in manumatic mode why the does it kick down..that makes no sense. With the gobs of torque, shifting down doesn't always make things quicker.
What the hell are you talking about. The car is controlled by a computer how wouldn't it know what's a safe gear to drop too. What I meant by it will drop down to the safest gear is simple. If you are in the right gear at the right rpms for the turn it won't kickdown if it doesn't have too.
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      06-26-2009, 08:51 PM   #28
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Quote:
Originally Posted by hsleiman View Post
I think he meant if the engine still has some room to downshift without going over redline it will if you kickdown. If you're already in a low gear at high rpm and try to kickdown it won't downshift because that will over rev the engine.

I don't understand what the big deal is? Don't hammer your foot down and it won't kickdown. Just put enough pressure down to not trip the kickdown you still get 100% WOT without a downshift. I think kickdown was put there for safety reasons. If you have some noob driving in manumatic in too high of a gear and suddenly realizes he needs to accelerate quickly, kickdown will put him in the right gear.
Thank you very much.
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      06-26-2009, 09:47 PM   #29
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Quote:
Originally Posted by Terrance28 View Post
What the hell are you talking about. The car is controlled by a computer how wouldn't it know what's a safe gear to drop too. What I meant by it will drop down to the safest gear is simple. If you are in the right gear at the right rpms for the turn it won't kickdown if it doesn't have too.
LOL. It's not as simple as that on a track...I'm sure its fine for street driving. You are talking safe kickdown for the engine/tranny and I'm talking safe kickdown while in a turn ...two different things.

LOL again for kickdown for safety reasons...in case someone has to accelerate quickly??

I am positive I would be able to adapt to know where the threshold for kickdown is, but I still think it is very dumb.
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      06-26-2009, 10:07 PM   #30
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Quote:
Originally Posted by 335lvr View Post
LOL. It's not as simple as that on a track...I'm sure its fine for street driving. You are talking safe kickdown for the engine/tranny and I'm talking safe kickdown while in a turn ...two different things.

LOL again for kickdown for safety reasons...in case someone has to accelerate quickly??

I am positive I would be able to adapt to know where the threshold for kickdown is, but I still think it is very dumb.
Umm yes for safety reasons I can immediately think of 2 or 3 situations where it would be beneficial to accelerate quickly. Some might argue the ability to accelerate quickly is just as important as the ability to slow down quickly when attempting to avoid an accident.

Also, if you are tracking your car I hope you possess the fine motor skills needed for throttle modulation and if you were in the right gear when exiting a turn kickdown should not be a factor. And if you track your car you might want to consider getting a stick. Auto boxes were devised so less input from the driver would be needed and on a track I would think that you would want as much control over your car as possibe.
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      06-26-2009, 11:31 PM   #31
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Quote:
Originally Posted by Mr. 5 View Post
Then can you explain why an auto has this button and the manuals don't?
If there isn't an actual button then why even have it?
It's for people who are used to driving cars back in the day that actually had a switch that you could feel. It's a placebo.
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      06-26-2009, 11:36 PM   #32
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Quote:
Originally Posted by 335lvr View Post
Not true, how does it know when to drop-down safely? Its not like it knows your in a tight turn and shifting down will upset the balance.
It absolutely does know if you're in a tight turn and shifting will upset the balance. It uses several sensors. Steering angle sensor, DSC rotation rate sensor, and other inputs to know that you're in the middle of a turn, and will do it's best to keep the same gear.
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      06-26-2009, 11:41 PM   #33
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Quote:
Originally Posted by 335lvr View Post
LOL. It's not as simple as that on a track...I'm sure its fine for street driving. You are talking safe kickdown for the engine/tranny and I'm talking safe kickdown while in a turn ...two different things.

LOL again for kickdown for safety reasons...in case someone has to accelerate quickly??

I am positive I would be able to adapt to know where the threshold for kickdown is, but I still think it is very dumb.
I understand what you are saying, but the easy solution is if you are in the right gear when you are going through a corner the kickdown feature is not an issue because the car would not need to kickdown because you are already in the right gear to accelerate out of it.
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      06-27-2009, 12:11 AM   #34
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Quote:
Originally Posted by SoCalTech View Post
It's for people who are used to driving cars back in the day that actually had a switch that you could feel. It's a placebo.
No it's not. The purpose of the kickdown is to put your car in a low enough gear to maximize acceleration. This is the same as flooring it in any other auto car. You floor it, the car will downshift, and you will accelerate. BMW has chosen to incorporate the "kickdown" feature to fine tune the behavior of the vehicle. If you want to accelerate without downshifting, you can push the pedal to the resistance point. If you want maximum acceleration and the car to behave just like any other car when you floor it, you push past the resistance point to engage kickdown. Obivously, manual transmission cars do not need this feature as the shifting is controlled solely by the driver and not the ecu.
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      06-27-2009, 12:28 AM   #35
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The "button" that you feel is a placebo. Take the pedal apart and see for yourself. There is no message sent to the DME saying "the kickdown button was pushed". There is no wiring, sensor, or signal associated with the actual feeling of pushing the "kickdown switch".
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      06-27-2009, 01:03 AM   #36
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Somewhat unrelated, but I was surprised that the Saturn Vue SUV will hold the gear, at redline, when in manual mode and full throttle! At least in 1st gear, I didn't test any of the others specifically, but I don't remember it kicking down when mashing the accelerator.

It was a Hertz rental car, otherwise I'd never get close to the thing.....
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      06-27-2009, 01:24 AM   #37
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Quote:
Originally Posted by SoCalTech View Post
The "button" that you feel is a placebo. Take the pedal apart and see for yourself. There is no message sent to the DME saying "the kickdown button was pushed". There is no wiring, sensor, or signal associated with the actual feeling of pushing the "kickdown switch".
"Placebo" or not, the car still behaves the way I described.
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      06-27-2009, 02:06 AM   #38
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To the OP:

Do this:

http://www.e90post.com/forums/showth...sable+Kickdown
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      06-27-2009, 08:39 AM   #39
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just buy a manual and you don't have to worry about your car driving you :P
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      06-27-2009, 08:41 AM   #40
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According to OBDII data, the car is at full throttle before the kickdown is pressed... pushing the "button" does not open the throttle plate any further in my testing. The last bit of pedal travel (the kickdown) tells the car to downshift.
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      06-27-2009, 11:38 AM   #41
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Quote:
Originally Posted by RiXst3r View Post
According to OBDII data, the car is at full throttle before the kickdown is pressed... pushing the "button" does not open the throttle plate any further in my testing. The last bit of pedal travel (the kickdown) tells the car to downshift.
So using that block of wood really does work, I would have never believed it, haha.
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      06-27-2009, 02:26 PM   #42
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Quote:
Originally Posted by RiXst3r View Post
According to OBDII data, the car is at full throttle before the kickdown is pressed... pushing the "button" does not open the throttle plate any further in my testing. The last bit of pedal travel (the kickdown) tells the car to downshift.
THANK YOU. Damn people is it that hard to understand.
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