GTS Steering parts/ calibration

[hotrod2448]

I wanted to start a discussion on the steering components of the M3/4. I saw some info that peaked my interest in this thread:
http://f80.bimmerpost.com/forums/sho....php?t=1181180

Steering
Adapted to the BMW M4 GTS
No elastic section in M4 GTS steering column for improved feedback
Steering torque curve optimized by modifications to the front suspension kinematics and incorporating asymmetric steering support mounts and a motorsport-derived, custom-designed, milled swivel bearing which allows optimized axle geometry for lateral dynamics and steering torque.
Swivel bearing also allows the use of 9.5 inch wide front wheels
Front camber set to minus degree setting for increased cornering lateral forces
Higher damper clamp with the ball joint in the front axle support mount results in substantially increased camber stiffness and provides faster response to lateral forces, which is already enhanced by the wider wheels (19 inch front wheels / 20x10.5 inch rear).

The main thing that's been bugging me the more I drive the car is the electric power steering. I may be overly sensitive on this but, it just feels really over dampened and artificially weighted to me.

It seems to me eliminating anything elastic within the column would provide an increase in feedback. The swivel bearing sounds like a rod end to me. Does anyone know the part they are talking about? Are there any aftermarket solutions for these items already available?

[M3Tooner]

I'm guessing the swivel bearing refers to the strut top mount, like a camber plate except non adjustable. I thought I read in the press release that the camber has been set to -2 degrees, that itself would tip the strut top inboard and allow for the wider 9.5 inch wheel. Although -2 degrees doesn't seem a lot, I thought stock M3/4 alignment was around -1 to -1.5?

[DocWeatherington]

hotrod2448 M3Tooner

Someone say comp pack... I think the steering adjustment, exhuast, rims and tires, updated diff.. maybe.. just maybe the water injection will be the comp pack.

[hotrod2448]

I agree the swivel bearing is probably the top mount for the struts.

I looked at the drawing for the steering wheel down to the rack and I'm having hard time finding this elastic section. I'm guessing it's integral to the column unless they do something really odd with the part where it passes through the firewall.

http://www.realoem.com/bmw/enUS/show...diagId=32_2305

[M3Tooner]

I'm guessing that the elastic section is the portion just below where it is labeled no.2 on the diagram from the link you posted. See how the shaft diameter grows larger there? I've seen some applications similar to this where they put rubber between the small shaft and the large shaft, unlike the more commonly used rubber doughnut design.

Anyway from my experience, this rubber coupling is mainly for NVH isolation. EPS systems tend to have a lot of weird noises come through the cabin without this. So it is not needed if you are more concerned about steering feel.

[hotrod2448]

Without seeing the construction of the column it's hard to say. Not surprisingly there aren't a lot of pictures of the current gen M3/4 steering column out there right now but, I did find this from an E46. It looks like there is a guibo in the steering shaft. I wonder if there is a similar part in the F80 where the column meets the rack.
http://prussianmotors.com/Empower/Pi..._002434_01.jpg

[M3Tooner]

Looks like I was wrong about the swivel bearing being the strut top mount. BMW is calling the "steering knuckle" as the swivel bearing. See link below.

http://www.realoem.com/bmw/enUS/show...22#31217853640

[Tom (Atl)]

I agree with you completely on the steering. It is unfortunately one of the weak points of the car. Even for electric steering I have driven much better. Granted some of those cars cost more but I still really wanted and hoped for true m level steering and feedback from the wheel.

[hotrod2448]

Originally Posted by Tom (Atl)

I agree with you completely on the steering. It is unfortunately one of the weak points of the car. Even for electric steering I have driven much better. Granted some of those cars cost more but I still really wanted and hoped for true m level steering and feedback from the wheel.

I have to say it's my biggest disappointment with the car. The amount of force required in sport and sport + for daily driving is just dumb and comfort (where I spend most of my time) while providing enough assist feels more like a driving simulator than a real car. There is no road feel through it.

Unfortunately I've been too busy lately to research the GTS parts and I still haven't read confirmation of if they actually help feedback or not. I'm hoping it helps provide some feedback and is something we can retrofit.

[stranger]

Subbed

[hotrod2448]

So the GTS column and rack parts look to have the same numbers as the normal F8X.
http://f80.bimmerpost.com/forums/sho....php?t=1233790