Active suspension - how does it work?

[swifty]

I don't think the same company Delphi or whoever runs them now(brand MagneRide) makes it for BMW. I know they do for Ferrari, GM and few Audi models. Think BMW EDC is similiar in concept tho.

[dparm]

Originally Posted by swifty

I don't think the same company Delphi or whoever runs them now(brand MagneRide) makes it for BMW. I know they do for Ferrari, GM and few Audi models. Think BMW EDC is similiar in concept tho.

Correct, BMW is not using Delphi stuff AFAIK.

BMW's OEM is typically Sachs.

[kenwelch]

Originally Posted by swifty

Reviving an old thread...

How quickly does it change from say comfort to normal after you hit the button?

By the time you take your finger off the button.
Dampening changes also happen as you drive based on the frequency of the suspension movement. The flow control valves change the orifice size in milliseconds like a fuel injector.

[cannga]

Originally Posted by kenwelch

By the time you take your finger off the button.
Dampening changes also happen as you drive based on the frequency of the suspension movement. The flow control valves change the orifice size in milliseconds like a fuel injector.

Very interesting and helpful thread. The size of the orifice actually changes?

The reason I ask is in the Porsche Turbo's version of EDC, to best of my knowledge, it is an on or off action, not a change in size. In other words, the damper has two valves, one of the 2 valves is either open (more fluid allowed to pass as piston moves up or down - soft setting) or closed (less fluid allowed to pass - stiffer). I am NOT sure about this though; it does seem to make more sense that the diameter of the orifice changes in size as this would allowed infinitely more variation than open/closed.

[EvenSteven]

I always figured the little elves that are always frying eggs when I turn the engine off were responsible.

[spr]

This IS correct. And the shocks, springs, EDC program are in fact different for ZCP EDC v. regular EDC.

Originally Posted by dparm

There is missing/incorrect information in this thread, so allow me to set the record straight:

Cars without Competition Package (ZCP):
-comfort is dynamic
-normal is dynamic
-sport is static


Cars WITH Competition Package (ZCP):
-comfort is dynamic
-normal is dynamic
-sport is dynamic



Some drivers do not like the stiffer ride settings and feel it is too artificial since it isn't providing them the right amount of feedback. A few tests showed that lap times in the different modes were not vastly different. The purists shy away from it entirely.

My advice is to use comfort for your street driving (unless you like having your teeth rattled out), and to experiment with the three settings when on the track. It's quite subjective in many ways.

[kenwelch]

I found this description also about how EDC is used in their vehicles:

http://www.bmw.co.za/products/automo...safety/edc.asp

[CanAutM3]

Originally Posted by dparm

There is missing/incorrect information in this thread, so allow me to set the record straight:

Cars without Competition Package (ZCP):
-comfort is dynamic
-normal is dynamic
-sport is static


Cars WITH Competition Package (ZCP):
-comfort is dynamic
-normal is dynamic
-sport is dynamic



Some drivers do not like the stiffer ride settings and feel it is too artificial since it isn't providing them the right amount of feedback. A few tests showed that lap times in the different modes were not vastly different. The purists shy away from it entirely.

My advice is to use comfort for your street driving (unless you like having your teeth rattled out), and to experiment with the three settings when on the track. It's quite subjective in many ways.

Your clarification is correct. However, note that the orginal thread dates back to 2009 when ZCP was not yet available .

[XYR03]

Very informative...I did not know this about my M thank you

[EvenSteven]

Originally Posted by dparm

There is missing/incorrect information in this thread, so allow me to set the record straight:

Cars without Competition Package (ZCP):
-comfort is dynamic
-normal is dynamic
-sport is static


Cars WITH Competition Package (ZCP):
-comfort is dynamic
-normal is dynamic
-sport is dynamic



Some drivers do not like the stiffer ride settings and feel it is too artificial since it isn't providing them the right amount of feedback. A few tests showed that lap times in the different modes were not vastly different. The purists shy away from it entirely.

My advice is to use comfort for your street driving (unless you like having your teeth rattled out), and to experiment with the three settings when on the track. It's quite subjective in many ways.

Sport is too choppy/bouncy; all the power in the world can't help you when your wheels are constantly hopping off the ground. Maybe on a glass-smooth Nascar ring that mode is useful.

I go between comfort and normal for all driving situations. Comfort for leisurely driving or particularly bad roads, normal for aggressive driving or particularly good ones.

[Beamerbiggs]

Ferrofluid Demonstration

[dparm]

Originally Posted by EvenSteven

Sport is too choppy/bouncy; all the power in the world can't help you when your wheels are constantly hopping off the ground. Maybe on a glass-smooth Nascar ring that mode is useful.

I go between comfort and normal for all driving situations. Comfort for leisurely driving or particularly bad roads, normal for aggressive driving or particularly good ones.

I agree that "sport" is most useful on a smoother surface. The track's elevation changes may come into play as well.

But that's why EDC is nice: you can pick the setting that works best for your driving style and skill. I would be curious what the instructors do at the M Performance Driving Schools in both the US and at the Nurburgring. I could've sworn I saw photos of the instructor M3s being sedans on the 18" wheels.

[Racer20]

There are generally two types of EDC systems out there: fluid based (Delphi's MR system) and solenoid based (all the others). Most of the solenoid based systems do NOT vary orifice size . . . they vary pilot pressure. As fluid enters the solenoid valve, it is split into two flow paths. One path builds pressure to open a valve, the other path flows around to the BACK of that valve and builds pressure to keep it closed. By varying the amount of current to the solenoid, the system changes how much oil goes to each side of the valve, which increases or decreases the pressure required to open it.

[swifty]

^ So which one is better?

[the_road_less_traveled]

Originally Posted by aus

The GM/Ferrari shocks have tiny metal particles suspended in the fluid and the system is able to vary the thickness of the fluid by changing the charge through the fluid. It's pretty slick. I believe the EDC is a valve based system though.

Oh wow! Thats pretty ingenious. Fluid kinematic viscosity changes by applying an electrical charge to the fluid itself which contains conductive particles? All these smart phukers out there!!

[Racer20]

Originally Posted by xfirer1guy

Oh wow! Thats pretty ingenious. Fluid kinematic viscosity changes by applying an electrical charge to the fluid itself which contains conductive particles? All these smart phukers out there!!

It's actually a magnetic field, not an electric charge. It's a pretty cool system, but BMW doesn't use it. The new Audi S3 sedan will have it when it comes out next year, most Ferraris use it, and Cadillac V series cars and Corvettes have had it for a while.

[EvenSteven]

Originally Posted by dparm

I agree that "sport" is most useful on a smoother surface. The track's elevation changes may come into play as well.

But that's why EDC is nice: you can pick the setting that works best for your driving style and skill. I would be curious what the instructors do at the M Performance Driving Schools in both the US and at the Nurburgring. I could've sworn I saw photos of the instructor M3s being sedans on the 18" wheels.

Spartanburg's instructors told me to set everything to normal, particularly power. My school car was an '08 E90 on 18s, 64xxx on odometer. This was a year ago.

[Racer20]

Originally Posted by swifty

^ So which one is better?

MR has faster response, but solenoid based systems run at lower pressure and have much less friction. They can both be good if they are tuned properly.

[dparm]

Originally Posted by EvenSteven

Spartanburg's instructors told me to set everything to normal, particularly power. My school car was an '08 E90 on 18s, 64xxx on odometer. This was a year ago.

I'd have been interested to hear a recommendation if the car had the factory 19s and/or ZCP, as that gets you different EDC tuning in the Sport mode.

[Darkone]

I wonder why they would make the ZCP sport dynamic versus the non ZCP sport mode static?

[Darkone]

Originally Posted by Beamerbiggs

Ferrofluid Demonstration

This is an awesome video, real star trek shiz!
So the M3 does or does not use this technology?

[kenwelch]

Originally Posted by Racer20

There are generally two types of EDC systems out there: fluid based (Delphi's MR system) and solenoid based (all the others). Most of the solenoid based systems do NOT vary orifice size . . . they vary pilot pressure. As fluid enters the solenoid valve, it is split into two flow paths. One path builds pressure to open a valve, the other path flows around to the BACK of that valve and builds pressure to keep it closed. By varying the amount of current to the solenoid, the system changes how much oil goes to each side of the valve, which increases or decreases the pressure required to open it.

The BMW EDC-K system used in the E92 M3 and later model vehicles is an orifice based system and uses electromagnetism to operate the solenoid coil/armature. The control system and the electromagnetic field are not any slower in the BMW system than the required electromagnetic field changes in the Magneto-Rheological Real Time Dampening (MRRTD) system used in GM vehicles and others.

This might help you understand how the BMW EDC-K operates.

From the 4th Gen M3 manual:
“EDC-K is available for the first time in the E92 M3. EDC-K is an option and is based on the EDC-K in the E65.”


From the E65 Manual:
“Electronically Adjustable Dampers:
The front and rear axles are equipped with twin tube gas pressurized dampers supplied by Mannesmann Sachs Boge. The fully variable dampers are map controlled and do not have fixed stages.

Each damper incorporates an adjustable proportioning control valve on the piston. The
wiring harness for this valve is routed through the hollow piston rod. Damper oil flows
through this valve during compression and rebound. The control valve generates a pressure drop between the lower and upper chambers depending on the oil flow volume. The front and rear axles are separately activated to achieve an optimum response for vibrations in all driving conditions. The valves are deactivated in the event of a control module failure or when the ignition is switched "OFF". The dampers automatically rest in the hardest setting (without power). On vehicles equipped with Dynamic Drive, the spring struts have different valve configurations on the front and rear axles. The dampers are de-energized when the vehicle is stationary. They are energized initially from 5 km/h.

Infinitely Variable Control Valve:
Without power, the maximum hydraulic resistance is set by the screw (1), which pre-tensions the valve spring (6). This is the hardest damper setting, also known as the failsafe (rest) setting.

The valve spring provides maximum tension on the armature (7), which presses down on the EDC-K Damper valve (3). This in turn presses down on the floating seat ring (5) which offers resistance to the oil flow by restricting the orifices (indicated by arrows).

When the solenoid coil (2) is energized by the EDC-K control module, the armature is magnetically pulled upwards against the valve spring tension. The armature will exert less pressure on the EDC-K Damper valve. The tension is decreased on the floating seat ring decreasing the orifice restriction. The oil flow will increase, resulting in softer damping.

When the solenoid coil receives maximum power, the effect will be the lightest tension on the floating seat ring. The orifices are unrestricted, providing the softest damping.


Rebound Stage:
The armature is controlled (electronically) by the EDC-K control module to regulate the EDC-K Damper valve and floating seat ring positions which varies the resistance to oil flow by restricting the orifices.”