e90 Lower Arm Bush

[Schwepps]

Lower heat shields Sulu. The danger has passed. Flank speed ahead.

E46F, you're right in that it only changes the steering ratio at low speed. But I thought A/S only activates at low speeds and at high speeds, the ratio reverts to unassisted? When I tested both A/S and non-A/S back-to-back, I could only feel the difference in the parking lot, not once I got moving on the road. So what do do you mean by "it's more relaxed and not as tiring to drive over long distances?"

Also wonder how it counters yaw faster than an expert can. That runs counter to "just a servo to change the steering ratio" Sorry for going OT, but interesting to know.

 

[oligokoko]

if u suspect lower arm bush kong, there is an easy way to identify. this mostly happen on an e46 n now berjangkit to e90 oredi. e46 easy to detect n replace but e90 is a bit hard.

to identify damage :
1. engage D gear and release brake (while engine is on of course)
2. let d car roll freely for a while until it reaches a steady speed
3. start make an intermediate emergency brake a few times
4. if u can feel a spongy effect, d bush is OK
if u feel like a sudden jerk (sumthin like engine mounting koyak on jap cars) and a sound from lower front part of vehicle,
the wahlaa! there is ur prob, a kong control arm bush

alternative : u can also make a full turn steering (like making a u-turn), engage D n make tht sudden braking. u might feel this also. better if u have another guy looking at one of ur frt tyres. if d bush is completely kong, then u can see d frt tyres moving back n forth or sumthimes vibrate awkwardly.

as astroboy's detailed figure, e90 control arm bush can be replaced w/o having to change d control arm. they must remove n repace just d bush. it is cheaper but take sum time 2 remove n install d bush back. usually takes around 1/2 a day. if u r replacing one on an e90, pls do ask d technician to inspect d ball joint of d arm too. if d ball joint is already hard, then better to replace d whole arm coz frm my experience, replacing d ball joint only usually will damage d arm coz it is hard to get it in. better to get a new arm, which already include a new bush n ball joint. n d price is 1k++ per arm (not 5 digits as publish b4 by astroboy. mayb its a typo by d catalogue guys =D ).

so start inspecting ur control arm bush guys. usually this part will leak (e90) and torn (e46) or both. i recommend to inspect this if ur car have clocked 60k on mileage.

Happy troubleshooting !!!

 

[E46Fanatic]

If I remember right, the rack ratio during high speed is longer compared to the standard steering. For E90 A/S its 1.5 turns lock to lock on low speed, and on the highway its 3 turns lock to lock. I believe the normal and M sport E90 steering ratio is 2.92 (I think the E9x M3's ratio is 2.5 turns lock to lock). So on the highway, the A/S equipped car is a little more lazy and relaxed compared to the standard non A/S ratio and the M3.

Not too sure about the the exact way A/S works with the DSC as well tho. Definitely some integration, and my guess is that it varies the ratio according to your countermeasure input. I.e. if the DSC senses an opposite lock is required, then as you turn your steering angle to induce it, the steering angle sensor detects what you are trying to do and DSC shortens the steering ratio so that you achieve it faster?? Thats just my guess tho heh.

 

[Schwepps]

Hmmm...maybe, but I'm not sure that's it. Not exactly the best thing to happen: high speed into a corner, start to drift, and when you countersteer, you get a shock and find that the steering ratio has changed on you! It's the opposite of predictable control in a slide. Pretty strange statement by BMW that one.

 

[E46Fanatic]

Another possible way it works is say if DSC believes you need 14 degree angle countersteer and you turn at either 10 or 20 degrees it varies the ratio to try to achieve 14 degrees as the end result? Should test one of these days kaka.

 

[Schwepps]

Cannot be bro, that would be as Astro says: a mind of it's own (when it can't see the road and bend conditions as you can) Go try it on your next Sepang day

 

[astroboy]

With DSC on, it's impossible to slide or drift the car la wei.. boring!

So when off DSC, AS still working or not le? Then can try.. but then again, if off DSC, how would DSC pair with AS to create the effect E46F praised earlier?

Sorry if I ask too much, I think mix too much with Schwepps lio..

 

[E46Fanatic]

It seems like it modifies the steering angle based on driver input to stabilize the car. Sounds a bit like my 2nd hypothesis. I suspect that the steering angle of the front wheels it is able to vary in such conditions is limited and based on what it can vary from just changing the ratios. Thats my interpretation based on the writeup below and knowing what A/S can do. Any other interpretations..?

http://en.wikipedia.org/wiki/Active_Steering

One thing I have to give to BMW tho, is the amount of innovation and thought the engineers put into this. If I was to design it, I'd probably be happy with just varying the steering angles/ratios on normal driving. Integrating the program with DSC sounds so much more complex, but BMW engineers went all the way to push the technology limits and benefits.

Also it reads like the A/S countermeasure kicks in before DSC's braking program does. Makes more sense now. To quote Schwepps - "clever little car"!

-------
Active steering is a type of variable gear ratio steering technology introduced by BMW in 2003 which varies the degree that the wheels turn in response to the steering wheel. At lower speeds, this technology reduces the amount that the steering wheel must be turned -- improving performance in situations such as parking and other urban area traffic maneuvers. At higher speeds, the performance is such that the normal increased responsiveness from speed is avoided and it provides improved directional stability.

In a parking situation, the computer varies the ratio so that the steering wheel needs less than two turns to move the wheels lock to lock. As vehicle speeds increase, the steering ratio increases, so it takes larger movements of the steering wheel to move the wheels and that lessens the usually increasing vehicle response resulting from increased speed. Besides providing variable steering ratios, the computer is linked with the vehicle stability control system to aid in directional stability of the vehicle.

If the driver experiences a skid or slide because of poor road conditions, the Active Steering will react to information from the yaw rate sensors to modify the steering angle of the front wheels to stabilize the vehicle. This occurs much faster than the driver can react. If the Active Steering angle is not enough, then the Stability Control system intervenes to help as well.

Safety is one of the prime objectives of this system. Steering angle sensors on the steering column sense the direction the driver wants to go and the system only intervenes if the car is beyond stable limits. If an error or problem occurs in the electronics, the computer shuts down the operation of the electric motor, locking the ring gear of the planetary gear set and making it fixed ratio steering. Finally, if there is a problem inside the planetary gear unit, there is a second shaft that runs all the way through from the steering wheel shaft to the steering rack so that conventional steering is available.

 

[astroboy]

Too complex for a simple minded driver like me.. naahh... forget it!..

God has already determine how and where I steer..

 

[E46Fanatic]

Too complex for a simple minded driver like me.. naahh... forget it!..

God has already determine how and where I steer..

Makes sense why you choose to drive hard on wet roads with DSC off! kakakaka.



AB, just kidding K? Buy u a beer . We'll likely do after work beers at TDDI sometime this week. Will ping u.

 

[Schwepps]

Yeah E46F, I read that as a small countersteer correction by the car in advance of the driver or DSC stepping in. Sort of pre-DSC action. A few millisecs later, the driver also countersteers - so what happens if this results in too much countersteer dialed in? Too complicated if you ask me.

 

[haku]

Gents,

Sent my car to IA for detail inspection due to problem mention earlier. the culprits is the left absorber leaking. Now need to wait till next week for the part to come in & do replacement. I hope that BMW waranty will change it in pair rather than replacing the left side only.

So Hakeemi, try to check your absorber. My car only done 41+++km & age 1 yrs 4mth old already have leak absorber problem.:sigh:.

 

[hakeemi]

Gents,

Sent my car to IA for detail inspection due to problem mention earlier. the culprits is the left absorber leaking. Now need to wait till next week for the part to come in & do replacement. I hope that BMW waranty will change it in pair rather than replacing the left side only.

So Hakeemi, try to check your absorber. My car only done 41+++km & age 1 yrs 4mth old already have leak absorber problem.:sigh:.

ok, thanks haku. appreciate it.

Now, AB have to check his catalog again... hehe thanks AB :top:

 

[prujb]

minta tolong bro2 semua.haku punya keta e46 2002 punya steering lari2 kanan kiri kanan kiri.
steering pun ada free 1/2 inci>
tanya 3 workshop dia kata steering rack.
tanya lagi 2 workshop dia kata lower arm bush.
yang mana satu betul la...
sampai sikalang aku tak bikin lg.tolong beri jawapan yang pasti.
(budak baru belajar)
>lower arm bush sepasang rm700
>steering rack rm1600

any comment

 

[haku]

Guys,

sorry for the late response. Finally, after a long waiting, the pair of front absoreber arrive & sent my car to IA for 3 days (masuk wad daa)... now the car feel like brand new & there's no more swerving response to the steering. So confirm it's ABSORBER...

However, if you guys watching ASTRO Turbo - Auto Trader they did mention there is few problems in with regards to double wishbone on the earlier E90's generation. Touchwoods for what I've said as it will cost us a bomb to replace those wish & the bones...

Finally, for those who have the same symptom as my car, try to get specialist to check the absorber too, as me myself couldn't even see the leak with my barenaked eyes.

And believe me, the replacement part arrive almost one month after my last post....gosh..

 

[jgc309]

Thanks Haku for the update. I've got the same symptom for my E90. Better get it checked up @ IA.

Guys,

sorry for the late response. Finally, after a long waiting, the pair of front absoreber arrive & sent my car to IA for 3 days (masuk wad daa)... now the car feel like brand new & there's no more swerving response to the steering. So confirm it's ABSORBER...

However, if you guys watching ASTRO Turbo - Auto Trader they did mention there is few problems in with regards to double wishbone on the earlier E90's generation. Touchwoods for what I've said as it will cost us a bomb to replace those wish & the bones...

Finally, for those who have the same symptom as my car, try to get specialist to check the absorber too, as me myself couldn't even see the leak with my barenaked eyes.

And believe me, the replacement part arrive almost one month after my last post....gosh..

 

[jgc309]

Thanks Haku for the reply. I'll have to bring my e90 for inspection as I've got the same symptom.

Guys,

sorry for the late response. Finally, after a long waiting, the pair of front absoreber arrive & sent my car to IA for 3 days (masuk wad daa)... now the car feel like brand new & there's no more swerving response to the steering. So confirm it's ABSORBER...

However, if you guys watching ASTRO Turbo - Auto Trader they did mention there is few problems in with regards to double wishbone on the earlier E90's generation. Touchwoods for what I've said as it will cost us a bomb to replace those wish & the bones...

Finally, for those who have the same symptom as my car, try to get specialist to check the absorber too, as me myself couldn't even see the leak with my barenaked eyes.

And believe me, the replacement part arrive almost one month after my last post....gosh..