Next Level Auto Brokers
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read

Go Back   BMW M3 and BMW M4 Forum > BMW F80 M3 / F82 M4 Forum > BMW M3 (F80) and BMW M4 (F82) General Forum

Post Reply
 
Thread Tools Search this Thread
      07-01-2014, 08:35 AM   #1
Jason
Administrator
Jason's Avatar
United_States
40111
Rep
21,227
Posts

Drives: F80 M3
Join Date: Mar 2005
Location: USA

iTrader: (0)

Lightbulb BMW M3 / M4 Chassis: Deep Dive and Interview

BIMMERPOST NEWS
BMW M3 / M4 Chassis: Deep Dive and Interview
35
COMMENTS

The following comes courtesy of M-Power.com.

Also see:
BMW M3 and BMW M4 Inside (part 1): The new M Servotronic.
BMW M3 and BMW M4 Inside (part 2): The Brake Systems.
BMW M3 and BMW M4 Inside (part 3): The new engine.
BMW M3 and BMW M4 Inside (part 4): Sound and Exhuast System.
BMW M3 and BMW M4 Inside (part 5): smartly light, rigid, precise.
BMW M3 and BMW M4 Inside (part 6): The new chassis.
BMW M3 and BMW M4 Inside (part 7): The Active M differential.


BMW M3 and BMW M4 Inside (part 6): The new chassis.
Interview with M engineer
Berd Barbisch.
July 1, 2014

Name:  1.jpg
Views: 22171
Size:  31.2 KB
The specialist areas of M engineer Bernd Barbisch: Development and testing of conventional and regulated spring/damper systems and axle/elastokinematics. His department also had a major role to play in the development of the rigidity package for the new BMW M3 and BMW M4.

Mr. Barbisch, the BMW M3 that has now been replaced already had an excellent suspension …?

Bernd Barbisch: The previous BMW M3 already offered a very good suspension basis. It was a benchmark - the one to beat.

How?

Using intelligent lightweight construction we were able to take a considerable step forward in terms of driving dynamics.

Name:  2.jpg
Views: 22428
Size:  437.4 KB
Role model: BMW M3 CSL.


The role model here was the BMW M3 CSL, where reduced weight again permitted an increase in potential transverse dynamics.

Name:  3.jpg
Views: 43079
Size:  198.2 KB
Double-joint spring strut front axle in the BMW M3 and BMW M4 in aluminium construction.


The axle design is completely new and entirely M specific, in other words no parts have been adopted from the base model. This elaborate design significantly enhances performance, driveability and response.

Name:  4.jpg
Views: 23848
Size:  117.6 KB
Five-link rear axle in the BMW M3 and BMW M4. Control arms and wheel carriers in aluminium construction, rear axle support in steel lightweight construction, rigidly connected to the body.


Name:  5.jpg
Views: 21859
Size:  217.6 KB
Rear axle control arm and wishbone optimised for rigidity and weight in the BMW M3 and M4, in aluminium forging technology.


Name:  6.jpg
Views: 22091
Size:  254.8 KB
Forged aluminium rear axle wheel carrier in the BMW M3 and BMW M4.


The premise was to maintain the good driveability of the previous BMW M3 but considerably increase performance at the same time. You'll be able to see this in the lap times achieved.

Name:  7.jpg
Views: 21553
Size:  470.1 KB
Test report in sport auto 7/2014 [LINK].


The new BMW M3 and BMW M4 are now offered with two different damper systems again: the standard suspension and the controlled Adaptive M suspension. What's new?

In the standard suspension there are new dampers. They enable much less phase shift in response as compared to the predecessor system, and therefore even more grip. Customers will notice this clearly when driving over poor surfaces, for example.

What does "less phase shift" mean?

A damper converts a speed into a force so as to keep the wheel on the ground. The faster the wheel passes through the rebound and compression phases, the greater the force. If you look at this in terms of the frequency of superstructure excitation and wheel excitation, the correct phase between speed and force is now applied across a much expanded operating range. When the phase between excitation and damping is not right, the damper becomes a spring at some point - increased wheel load fluctuations occur and road surface contact is impaired.

And in the Adaptive M suspension?

In this regulated suspension we wanted to at least equal the comfort of the predecessor model but also achieve a clear increase in sportiness.

Name:  8.jpg
Views: 23166
Size:  100.2 KB
Adaptive M suspension.


For this purpose we are using an even more effective system of sensors in the car. For example, there are now wheel acceleration sensors at all four dampers which assess the state of the road surface, so to speak. Based on this data, the damping is recalculated and regulated at every damper every 2.5 milliseconds so as to set the optimum level of damping force - and that can vary considerably between each of the four wheels. So the damping at one wheel could be considerably softer, while at another it might be much tighter.

Name:  9.jpg
Views: 21432
Size:  224.4 KB
Lightweight aluminium adjustment damper of the Adaptive M Suspension with wheel acceleration sensor.


Our regulation approach is the so-called "skyhook": the regulation strategy applied by the damper logic ensures that the automobile is always guided by the sky, if you like. Here the damping is regulated based on the movement of the entire automobile. With other regulation elements we then create the best possible connection with the road. In addition there is a new sensor cluster used in the vehicle which measures lift, pitch and roll acceleration, thereby registering the movement of the car's superstructure. The automobile moves more calmly and supremely.

The regulated damper itself has also been refined. We are now able to achieve a much greater spread in the damping - especially in terms of the direction of pressure. We went to the limits of what is possible with damper technology so as to achieve optimum race track performance combined with everyday practicality. And the dampers are much lighter than in the base model due to the fact that they are made of aluminium.

A so-called 3-path support bearing is now used, too. The damper has its own power transmission path to the body - the forces of the bearing spring and the ancillary spring are transmitted rigidly via separate paths.

Name:  10.jpg
Views: 27546
Size:  288.6 KB
3-path support bearing in the front axle of the BMW M3 and BMW M4. This is the link between the body and the spring/damper elements.


What is the advantage of this?

Previously the ancillary spring could shift the bearing when the wheel was compressed - this meant the damper was not always in the ideal operating range. The decoupling means that the damper now operates perfectly in phase, regardless of whether the wheel is in compression or rebound. In this way we achieve maximum body cohesion.

Which of the modes COMFORT, SPORT and SPORT PLUS of the Adaptive M suspension can the standard suspension best be compared to?

That's a relatively difficult question to answer. Due to the elaborate regulation logic and sensor system, the Adaptive M suspension is able to achieve superstructure cohesion and increased comfort at the same time. This is usually the conflict you always have with the suspension set-up: achieving the best possible cohesion so as to be able to run on demanding tracks like the Nürburgring Nordschleife as fast as possible, for example - but also retaining the required amount of comfort for everyday driving. The car mustn't demonstrate any after-response or pumping, let alone take off over hollows and crests. In terms of superstructure cohesion, the standard suspension is somewhere between SPORT and SPORT PLUS, in terms of comfort it is more equivalent to SPORT PLUS.


Name:  11.jpg
Views: 21615
Size:  128.6 KB


Leaving the aspect of comfort aside, which is important in everyday driving, and just looking at the car's driving dynamics qualities: is the Adaptive M suspension superior from this one-sided point of view as well?

In the standard suspension we tried to achieve the best possible compromise over all possible race track profiles. In the case of the regulated Adaptive M suspension, even more individual adaptation is possible here. On the Nürburgring Nordschleife I personally use SPORT mode. On a fairly level race track, however, SPORT PLUS would be the best choice.

In any case: with extreme grip potential, the new BMW M3 and BMW M4 still remain very driveable at all times.

The data measured by the sensors impacts dynamically on the suspension set-up. You might say that the standard suspension is set up once, while the Adaptive M suspension is set up every 2.5 milliseconds?

(laughs). Correct.

Can this result in an overlap of the setting ranges? In other words, even the COMFORT setting could lead to the suspension being tightened significantly if required by the relevant manoeuvres?

There are manoeuvres where the COMFORT setting is just as sporty as in SPORT and SPORT PLUS. Maximum damping power potential is used here, regardless of the setting.

What manoeuvres are these?

Initial steering approaching bends, changing lane, slalom etc.

You already mentioned that you yourself use the SPORT on the Nürburgring Nordschleife and SPORT PLUS on level race tracks. What about when you're driving in everyday traffic ...?

There I definitely use the COMFORT setting. (laughs). The new BMW M3 and BMW M4 now start for the first time in SPORT mode. My M1 button at the steering wheel is pre-set to DSC OFF, with steering and dampers in COMFORT.

Last year you were at Nürburgring doing set-up runs with the DTM driver Bruno Spengler. How did that go?


Video: Berd Barbisch and DTM race driver Bruno Spengler at the Nürburgring.


It was remarkable how quickly Bruno felt his way to the limit. And that's what is so striking about the BMW M3 and BMW M4 for the normal driver, too: the car always remains eminently driveable in spite of the extreme grip potential. That's always the difficulty in general: the closer you get to the physical limits in terms of the car's balance, the greater the challenge in getting the car to respond quickly. As you can see in the new BMW M3 and BMW M4: the driver simply gets in, drives off and can immediately drive fast, on the race track for example. And that's a key aspect of the M philosophy: driving response and the car's reactions always have to be predictable and convey a sense of trust.

Did the test runs with Bruno Spengler and Timo Glock contribute to achieving this?

Bruno had an idea regarding the transverse rigidity of the tyres and we implemented that. Ex-Formula 1 driver Timo Glock's input in terms of the steering was also taken on board.


Video: Test drives of the race drivers Timo Glock and Bruno Spengler.

It was exciting to see how much overlap there was between the racing drivers' point of view and that of our set-up experts and how quickly they came together.

Mr. Barbisch, thank you very much for the interview.


Appreciate 1
      07-01-2014, 09:00 AM   #2
Brosef
Brigadier General
Brosef's Avatar
United_States
872
Rep
3,446
Posts

Drives: F90 M5
Join Date: Aug 2009
Location: Chicago

iTrader: (4)

great info on the suspension. thanks
Appreciate 0
      07-01-2014, 10:40 AM   #3
CanAutM3
General
CanAutM3's Avatar
Canada
21103
Rep
20,741
Posts

Drives: 2021 911 turbo
Join Date: Jan 2012
Location: Montreal

iTrader: (1)

Garage List
Nice read.

Appreciate 0
      07-01-2014, 10:56 AM   #4
BlackCobra08
King Cobra
BlackCobra08's Avatar
108
Rep
450
Posts

Drives: incoming GTS 4.0
Join Date: Mar 2014
Location: MN

iTrader: (0)

Amazing! On my drive into work this morning I was just wondering if there were going to be anymore of these 'Deep Dive and Interview' parts. Thanks Jason!
Appreciate 0
      07-01-2014, 11:09 AM   #5
BD SM3RF
Captain
BD SM3RF's Avatar
United_States
277
Rep
772
Posts

Drives: 2015 YMB F80
Join Date: Aug 2011
Location: Dallas TX

iTrader: (1)

Garage List
2015 BMW M3  [0.00]
2016 BMW X3  [0.00]
2011 BMW 135i  [0.00]
I was waffling about Adaptive but I will now check that box.
Appreciate 0
      07-01-2014, 11:20 AM   #6
1stm3f80
First Lieutenant
1stm3f80's Avatar
United_States
48
Rep
380
Posts

Drives: F80 ///M3
Join Date: Apr 2014
Location: San Diego

iTrader: (0)

I went passive. F it I'd be in sport all the time anyways.
Appreciate 0
      07-01-2014, 11:23 AM   #7
rick berry
Second Lieutenant
11
Rep
268
Posts

Drives: 2015 M4 DCT/ 2014 750li
Join Date: Jul 2007
Location: marshall texas

iTrader: (0)

Great technical info. It always impresses me how much detail goes into transforming a "regular" BMW into an M car.
Appreciate 0
      07-01-2014, 11:44 AM   #8
RickMonet
Lieutenant
RickMonet's Avatar
175
Rep
500
Posts

Drives: 2015 M3 6MT
Join Date: Jun 2014
Location: Bay Area, CA

iTrader: (0)

Looks like daily driver needs Active M Suspension to have the ability to be in Comfort mode:

"... In terms of superstructure cohesion, the standard suspension is somewhere between SPORT and SPORT PLUS, in terms of comfort it is more equivalent to SPORT PLUS."
Appreciate 0
      07-01-2014, 12:45 PM   #9
swagon
Major General
swagon's Avatar
No_Country
13478
Rep
8,144
Posts

Drives: F80 6MT
Join Date: Jun 2013
Location: .

iTrader: (0)

Quote:
Originally Posted by RickMonet View Post
Looks like daily driver needs Active M Suspension to have the ability to be in Comfort mode:

"... In terms of superstructure cohesion, the standard suspension is somewhere between SPORT and SPORT PLUS, in terms of comfort it is more equivalent to SPORT PLUS."
Nah, I don't think so. It is firm, but not too much stiff and hard.
__________________
Appreciate 0
      07-01-2014, 12:58 PM   #10
GoDucksYellO
New Member
5
Rep
28
Posts

Drives: F80 M3 2015
Join Date: Apr 2014
Location: Eugene, OR

iTrader: (0)

I have really enjoyed this series. Thanks for taking the time to put it together Jason.
Appreciate 0
      07-01-2014, 01:17 PM   #11
mkoesel
Moderator
United_States
7506
Rep
19,370
Posts

Drives: No BMW for now
Join Date: Jun 2006
Location: Canton, MI

iTrader: (1)

Truly fantastic information. You can't go wrong with either type of suspension. Great work by the M Division.
Appreciate 0
      07-01-2014, 01:31 PM   #12
stressdoc
Moderator
stressdoc's Avatar
Dominica
616
Rep
10,853
Posts

Drives: BMW i8; Toy 4runner TRD pro
Join Date: Jun 2005
Location: Waco TX

iTrader: (0)

Awesome!
Appreciate 0
      07-01-2014, 01:33 PM   #13
dhoggm3
Major
dhoggm3's Avatar
United_States
269
Rep
1,281
Posts

Drives: 850i C, Gated R8 5.2, E63
Join Date: Jul 2007
Location: Central PA

iTrader: (1)

Thank you. What a great tool this forum has been for me in my transition to the F80! Now I'm really glad I switched my order and added the adjustable suspension a few weeks ago.
__________________
M850i Vert with RaceChip
E46 M3, Euro Headers, Rasp Pipe, Kassel Tune
Alpina B8, zero performance mods
Appreciate 0
      07-01-2014, 01:40 PM   #14
ersin
Brigadier General
ersin's Avatar
United_States
124
Rep
4,145
Posts

Drives: 17 YMB F80 M3
Join Date: Mar 2008
Location: Maryland

iTrader: (1)

Quote:
Originally Posted by RickMonet View Post
Looks like daily driver needs Active M Suspension to have the ability to be in Comfort mode:
Not at all. My test drive was in a standard suspension equipped M4 and I wholeheartedly endorse the standard suspension for daily driving!


Cheers.
__________________
2017 F80 YMB.
Appreciate 0
      07-01-2014, 01:44 PM   #15
JoeFromPA
Colonel
1789
Rep
2,995
Posts

Drives: '15 AW M3 6MT Stripper
Join Date: Aug 2013
Location: SE PA

iTrader: (0)

After a test drive today, I can really appreciate some of this and feel the M-adaptive suspension is a must have and that at $1000 represents a reasonable value. It's not the handling limit, but the ride quality for daily driving while maintaining most appropriate damping/cohesion (as referenced here) that you simply can not get with fixed dampers and where this car really improves with the adaptive suspension.
Appreciate 0
      07-01-2014, 01:56 PM   #16
m5 guy
Brigadier General
m5 guy's Avatar
United_States
1662
Rep
3,198
Posts

Drives: 2020 M5 Comp
Join Date: Apr 2012
Location: Hawaii

iTrader: (14)

Great read, thanks for posting!
__________________
2020 F90 M5 Comp Oxford Green Metallic II-Aragon JOURNAL
2016 F10 M5 Space Gray-Black SOLD
2012 E70 X5M Monte Carlo Blue-Silverstone SOLD
2001 E46 M3 Oxford Green Metallic II-Cinnamon SOLD
Appreciate 0
      07-01-2014, 01:58 PM   #17
maupineda
Captain
United_States
442
Rep
959
Posts

Drives: E86 Z4MC
Join Date: Jul 2012
Location: Detroit, MI

iTrader: (3)

Does anyone else note the in-car sound in those videos are without active sound? and it sounds great indeed as the typical R6 engine. to me that stupid synthesized sound is complete useless and masks an otherwise great noise.
Appreciate 0
      07-01-2014, 02:11 PM   #18
tlp
Colonel
United_States
276
Rep
2,216
Posts

Drives: 991 GT3, Sold:'11 e92 M3 SG/FR
Join Date: Jul 2005
Location: Las Vegas/SoCal

iTrader: (6)

Garage List
Lots of opportunities for camber plate mfg's with the fixed guide pins on the top of strut guide. Would be interesting to see if more camber can be achieved by filing down the pins or if the receiving holes are oval shaped to allow adjustment. Nice implementation of weight saving techniques.

__________________
991 GT3, Sold: '11 e92 M3 SG/FR ZCP|ZCV|ZP2|2MK|494|415|6NR|752
Appreciate 0
      07-01-2014, 02:19 PM   #19
3M TAPE
Banned
3M TAPE's Avatar
No_Country
350
Rep
1,225
Posts

Drives: M3
Join Date: Mar 2007
Location: States

iTrader: (0)

Well well... I guess the Adaptive M suspension is a must for daily drivers.
Appreciate 0
      07-01-2014, 02:28 PM   #20
stressdoc
Moderator
stressdoc's Avatar
Dominica
616
Rep
10,853
Posts

Drives: BMW i8; Toy 4runner TRD pro
Join Date: Jun 2005
Location: Waco TX

iTrader: (0)

Quote:
Originally Posted by Double Bubble View Post
Well well... I guess the Adaptive M suspension is a must for daily drivers.
And the track and the dirt...

I was surprised to hear that Adaptive is lighter than passive.

So much M-specific engineering on the F8x. Coming from an E90 with tons of M3 suspension parts, that does not seem feasible this time around; so much special design on the F8x, truly a different car than the F30. This is really a distinctive, world class super car in sheep's clothing.
Appreciate 0
      07-01-2014, 02:38 PM   #21
modkrazy
Lieutenant Colonel
modkrazy's Avatar
169
Rep
1,531
Posts

Drives: m3
Join Date: May 2014
Location: tx

iTrader: (1)

Quote:
Originally Posted by maupineda View Post
Does anyone else note the in-car sound in those videos are without active sound? and it sounds great indeed as the typical R6 engine. to me that stupid synthesized sound is complete useless and masks an otherwise great noise.
Should be simple enough to pull the fuse.
Appreciate 0
      07-01-2014, 02:55 PM   #22
JoeFromPA
Colonel
1789
Rep
2,995
Posts

Drives: '15 AW M3 6MT Stripper
Join Date: Aug 2013
Location: SE PA

iTrader: (0)

Quote:
Originally Posted by stressdoc View Post
And the track and the dirt...

I was surprised to hear that Adaptive is lighter than passive.

So much M-specific engineering on the F8x.
Wait, what? Can you pull that quote - I'm not seeing it/finding it.

Edit, I see this: "And the dampers are much lighter than in the base model due to the fact that they are made of aluminium."

"Much lighter" huh? Be interested to know by how much. I thought this was going to increase weight.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:37 AM.




f80post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST