Drive by wire = E90 not obeying my foot ! - BMW 3-Series (E90 E92) Forum

skimo · 10-29-2005, 03:23 AM

Pulled out of work after parking under hot texas sun the other day. At the first light I was playing around with the throttle, I was trying to keep the RPM constant at 2k...IMPOSSIBLE !!

I push the throttle till it goes to 2k, without moving my foot the RPM would go down in obvious steps to say 1.5k then go back up...then go down...like my E90 was -->

Lets play another game: keep the RPM at 3k. same deal, the RPM kept changing alone even though my foot was constant not moving ! I wished I took a video (from phone) of the rpm...it clearly was jumping back n forth in increments of 100 rpm or so...

HONK HONK! My light turned green, but I was just too busy playing footsy with my E90...

This could explain why I can never learn how to get a smooth shift on this car !! The car is not obeying my feet !! CDV, Drive-by-wire...soon they will have "allow me to press the brakes for you"

(still love my car though

)

Skimo

Xens · 10-29-2005, 03:30 AM

Quote:

Originally Posted by skimo

Pulled out of work after parking under hot texas sun the other day. At the first light I was playing around with the throttle, I was trying to keep the RPM constant at 2k...IMPOSSIBLE !!

I push the throttle till it goes to 2k, without moving my foot the RPM would go down in obvious steps to say 1.5k then go back up...then go down...like my E90 was -->

Lets play another game: keep the RPM at 3k. same deal, the RPM kept changing alone even though my foot was constant not moving ! I wished I took a video (from phone) of the rpm...it clearly was jumping back n forth in increments of 100 rpm or so...

HONK HONK! My light turned green, but I was just too busy playing footsy with my E90...

This could explain why I can never learn how to get a smooth shift on this car !! The car is not obeying my feet !! CDV, Drive-by-wire...soon they will have "allow me to press the brakes for you"

(still love my car though

)

Skimo

Interesting ......... although I have to say, I decided to screw trying to get smooth shifts and just drive without thinking, and I'm actually shifting really smoothly now.

E90Fleet · 10-29-2005, 04:07 AM

You know thats very bad for your engine ( revving it witout a load )

System probably doesnt like it since your wheels arnt moving

puck724 · 10-29-2005, 05:19 AM

could someone explain drive by wire?

lux.sh · 10-29-2005, 06:10 AM

puck724, these articles will help you understand.

http://www.pitt.edu/~tas36/interesting%20event.html
http://www.worldwidewords.org/turnsofphrase/tp-dri1.htm

Basically, technology is being more and more adapted to our daily experiences.
Its doing the work while we don't even know when/how its done.

tiga901 · 10-29-2005, 10:30 AM

Moral of the story, learn how to drive a stick!!! Seriously, the rpm variation is normal. It's an auto adjustment by your ECU to the load.

mapezzul · 10-29-2005, 10:47 AM

The drive by wire is not designed to keep revs even, it is based on engine load and speed essentially. It is much smoother than in previous cars that would launch off the line.
It is designed to maximize the efficiency of the engine based upon the load presented without the need to adjust the pedal. So by the RPM's dropping off this is the computer doing what it is supposed to do, There is no load so it drops the engine a little to get the best fuel efficiency for the work required. It can not completely over ride your foot obviously other wise it would just remain at idle.

The E90 is much more responsive than others I have driven IMHO.

maq · 10-29-2005, 11:10 AM

I don't think uneven rpm is caused by DBW. But speaking of DBW, I find it to be really annoying, and it's one of the main reasons that've been keeping me away from the newer BMWs. Although in the E90 it's been improved a lot compared to the early E46s terrible throttle response (even the later ones and M3 kinda suck), I still find it doesn't "blip" too well. You just don't get that instant, super responsive revving that a non-DBW gives you.

ben1364 · 10-29-2005, 11:52 AM

maq wrote in part, "...it doesn't "blip" too well. You just don't get that instant, super responsive revving that a non-DBW gives you"
__________________________________________________ _
"blip"? I thought that was reserved for Harley Davidson riders to show off their mega buck LOUD exhausts? <g>

maq · 10-29-2005, 12:23 PM

Quote:

Originally Posted by ben1364

maq wrote in part, "...it doesn't "blip" too well. You just don't get that instant, super responsive revving that a non-DBW gives you"
__________________________________________________ _
"blip"? I thought that was reserved for Harley Davidson riders to show off their mega buck LOUD exhausts? <g>

By "blip", I meant the process of blipping the throttle (or in other words, quickly tap on the gas pedal) when rev-matching between gears. But yea, the Harley guys probably do it more than us Bimmerheads. And when they do it, everyone within a mile or 2 will hear it...

blueStreak · 10-29-2005, 01:47 PM

Quote:

Originally Posted by puck724

could someone explain drive by wire?

DBW = you are no longer in direct control of the throttle. Instead, you are just one of many inputs that the computer uses to determine the best throttle position. Personally, I think it sucks. For the general population, it's probably a great thing.

puck724 · 10-29-2005, 02:43 PM

thanks guys. ive heard of it before but never found out what it was..haha.

lux.sh- thanks for the articles.

skimo · 10-30-2005, 05:05 PM

Quote:

Originally Posted by E90Fleet

You know thats very bad for your engine ( revving it witout a load )

System probably doesnt like it since your wheels arnt moving

thanks for the tip!! I was not aware of this... Ill keep that in mind

skimo

10-29-2005, 03:23 AM	#1
skimo First Lieutenant Drives: 07 335i Dinan II Join Date: May 2005 Location: Austin Texas !! Posts: 398 iTrader: (1)	Drive by wire = E90 not obeying my foot ! Pulled out of work after parking under hot texas sun the other day. At the first light I was playing around with the throttle, I was trying to keep the RPM constant at 2k...IMPOSSIBLE !! I push the throttle till it goes to 2k, without moving my foot the RPM would go down in obvious steps to say 1.5k then go back up...then go down...like my E90 was --> Lets play another game: keep the RPM at 3k. same deal, the RPM kept changing alone even though my foot was constant not moving ! I wished I took a video (from phone) of the rpm...it clearly was jumping back n forth in increments of 100 rpm or so... HONK HONK! My light turned green, but I was just too busy playing footsy with my E90... This could explain why I can never learn how to get a smooth shift on this car !! The car is not obeying my feet !! CDV, Drive-by-wire...soon they will have "allow me to press the brakes for you" (still love my car though ) Skimo

10-29-2005, 05:19 AM	#4
puck724 COLTS 4 LIFE!!! Drives: 2006 330i Join Date: Aug 2005 Location: california Posts: 1,455 iTrader: (1) View puck724's Garage	could someone explain drive by wire? __________________ 2006 330i --sapphire black--black leather --alumminum trim --premium package --cold weather package --park distace control --automatic transmission --navigation with iDrive

10-29-2005, 06:10 AM	#5
lux.sh Hole-in-one. Drives: very smoothly. Join Date: Sep 2005 Location: Eugene, OR Posts: 3,680 iTrader: (11) View lux.sh's Garage	puck724, these articles will help you understand. http://www.pitt.edu/~tas36/interesting%20event.html http://www.worldwidewords.org/turnsofphrase/tp-dri1.htm Basically, technology is being more and more adapted to our daily experiences. Its doing the work while we don't even know when/how its done. __________________ 06 AW E90 330i ZPP/ZSP/Step : Hartge Front : ACS roof : BlkLines : Simota Intake : Blk CF trim : Exhaust valve mod : : Luminics Yellows : 24% Charcoal : V1 Hardwired : Solaris Invisibulbs/LED interior :

10-29-2005, 11:52 AM	#9
ben1364 Lieutenant Major Drives: E90 330iA Join Date: Aug 2005 Location: Georgetown, TX Posts: 944 iTrader: (0)	maq wrote in part, "...it doesn't "blip" too well. You just don't get that instant, super responsive revving that a non-DBW gives you" __________________________________________________ _ "blip"? I thought that was reserved for Harley Davidson riders to show off their mega buck LOUD exhausts? <g> Last edited by ben1364; 10-29-2005 at 11:53 AM. Reason: addition

10-29-2005, 02:43 PM	#12
puck724 COLTS 4 LIFE!!! Drives: 2006 330i Join Date: Aug 2005 Location: california Posts: 1,455 iTrader: (1) View puck724's Garage	thanks guys. ive heard of it before but never found out what it was..haha. lux.sh- thanks for the articles. __________________ 2006 330i --sapphire black--black leather --alumminum trim --premium package --cold weather package --park distace control --automatic transmission --navigation with iDrive

10-29-2005, 04:07 AM	#3
E90Fleet Major General Drives: BMW Join Date: Apr 2005 Location: South Africa Posts: 6,515 iTrader: (0)	You know thats very bad for your engine ( revving it witout a load ) System probably doesnt like it since your wheels arnt moving

10-29-2005, 10:30 AM	#6
tiga901 First Lieutenant Drives: e90 330i, mt pp sp Join Date: Sep 2005 Location: Millbrae, CA Posts: 245 iTrader: (0)	Moral of the story, learn how to drive a stick!!! Seriously, the rpm variation is normal. It's an auto adjustment by your ECU to the load.

10-29-2005, 10:47 AM	#7
mapezzul Special Agent Drives: Depends on the day! Join Date: Jul 2005 Location: New York Posts: 1,178 iTrader: (1)	The drive by wire is not designed to keep revs even, it is based on engine load and speed essentially. It is much smoother than in previous cars that would launch off the line. It is designed to maximize the efficiency of the engine based upon the load presented without the need to adjust the pedal. So by the RPM's dropping off this is the computer doing what it is supposed to do, There is no load so it drops the engine a little to get the best fuel efficiency for the work required. It can not completely over ride your foot obviously other wise it would just remain at idle. The E90 is much more responsive than others I have driven IMHO.

10-29-2005, 11:10 AM	#8
maq Lieutenant Drives: Imola 330i Join Date: May 2005 Location: Houston - NYC Posts: 467 iTrader: (0)	I don't think uneven rpm is caused by DBW. But speaking of DBW, I find it to be really annoying, and it's one of the main reasons that've been keeping me away from the newer BMWs. Although in the E90 it's been improved a lot compared to the early E46s terrible throttle response (even the later ones and M3 kinda suck), I still find it doesn't "blip" too well. You just don't get that instant, super responsive revving that a non-DBW gives you.