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C6 Suspension 'Pitching'

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Sat Jul 28 2012, 11:47pm
Joined: Nov 09 2011
Member No: #710
Location: Watford
The RX8 (and other Mazda RX cars) use a Mazda Rotary engine. It is a different design from the Wankel rotary engine, and while it may have been influenced by Wankel's early work, they were also researched separately.

The key weakness on the Wankel engines was the bearings as the rotary component moved round a fixed central shaft. Seal failure as a comparatively minor cause of failure - unlike on the Mazda rotary engine where the rotors are fixed to the central shaft, but you get tip failure and seal wear.
Sun Jul 29 2012, 08:11am
Joined: Oct 08 2009
Member No: #3
Location: North Yorkshire
The prototype flat 6 engines for the DS were made in both air cooled and water cooled forms but the later GS flat 4 was a completely different engine. The flat 6's are in the Conservatoire in Paris.
Sun Jul 29 2012, 09:15am
Joined: Sep 20 2010
Member No: #238
Location: Aldeburgh
Oh, yes, they are, but I could not get them to fire it up when I was there! Madame said that it was too difficult, etc etc. Pity...
Mon Jul 30 2012, 04:21pm
Joined: May 10 2011
Member No: #466
Location: London
Sorry to be pedantic, but all rotary engines were based on Felix Wankels concept. From a single totor to triple rotors, as in the MB C111. Mazda cured the tip sealing problem and used ceramics, but still had some problems with the side seals. The rotors orbited within the figure of 8 housing, driving a toothed eccentric shaft which transmitted the power to the flywheel. The rotors were not fixed to this shaft. A vidio from u tube can be found here: - Click Here -
Wed Jan 16 2013, 03:19pm
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
But are there any downsides to updating the engine, gearbox & suspension software?!? Can anything go wrong?!?
Wed Jan 16 2013, 11:09pm

Joined: Jan 24 2010
Member No: #38
Location: Celbridge

As previously posted I got the suspension update and never looked back. So I don't think you've anything to worry about.


Phil C.
Fri Jan 18 2013, 08:48am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
Thank you @cruiserphil! I have set an appointment for next Tuesday at my local Citro├źn Service, will do the updates and never look back

Fri Jan 18 2013, 09:01am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
@michaelb: Both the Merak & the Khamsin are on my CarPorn list - I even saw an UK produced Discovery Networks classic car TV show episode dedicated to the Merak where the presenter would argue that it's an immensely overlooked and under-appreciated classic sports car, the upside of this being that it is possible to find a good one at a very decent price (as low as GBP 10K, if I remember correctly)...

Tue Jan 22 2013, 07:49am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
Got the update! Will keep you posted in regards to the ride quality improvements (if any)...

Tue Jan 22 2013, 09:25am
Joined: Sep 30 2012
Member No: #1044
Location: Bonn
Sam, if you have any means to detect the version number of your suspension software you might help people (including me) to find out whether they got it already or not. My dealer is no help at all.

Not that I'd complain. Since my new spheres were fitted I am reasonably happy as far as ride quality is concerned. The pitching is quite reduced.
Tue Jan 22 2013, 08:12pm
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
Hi there @Pappnase,

Didn't remember the versions and have no means of checking that myself but I'd be more than glad to help...

First of all you have to know that there are 5 main computers on your C6:

- the SDI that controls the engine/injection map

- the AM6 that controls the 6-speed automatic gearbox

- the ABS/ESP (might also appear as ABS/ESP_CAN_40 or something similar) that controls electronic brake distribution with anti-lock feature, stability and traction control

- the SUSPENSION (might also appear as ECOTECH_SUSPENSION or something simmilar) that controls general suspension settings

- and the CSS which stands for Controle Systeme Suspension and is the official name of the computer that controls what people most commonly know as AMVAR which stands for Amortisation Variable and is available only on higher spec C6s (if you drive a 2.2 Lignage, the CSS will most likely not be listed or listed as Not Present).

So on the higher spec C6s there are in fact 2 computers that control suspensiopn, but as the document that Dave so kindly included in the begining of this thread specifies, this update only targets the CSS (AMVAR)...

I stood next to the Citroen engineer as he ran diagnostics and checked for updates and my car only needed the CSS to be updated, as the SDI, the AM6, the ABS/ESP and the SUSPENSION were all up to date.

So, the easiest way to know if your car needs the update or not is this... When connected to Citroen's official diagnosis and repair box (which is no longer Lexia, BTW, even though the engineer told me that in many ways Lexia was superior to what they are using now), after running the initial diagnosys on your car, all modules and faults are listed (if any)...

Next, you select the CSS module (or any other module for any computer on your car you would want to update) and you see a list of available operations.

Amongst these options you will see Repair.

As you click on it, you will have 2 options:

- Download Identification - which lists the current version installed on the car

- Download - which updates the software on that computer with the latest version available on the Citroen Service Network Servers

If you hit Download, you will be required a valid connection to the internet (connection test), then authentification and authorisation on the Citroen Service Network (username and password that the engineer will provide), then the software will connect to the server, download the latest available update, compare it to the version installed on your car and if it's newer install it. If not, you will be informed that "the latest version is already on the car and no update is required".

And that's how you know!

So, @Pappnase, that's what I suggest you do - ask to stand next to the engineer and as he navigates to the CSS module and hits Repair -> Download, you will know!

Sidenote: After doing the update I didn't notice any significant difference in the ride - it does seem a bit more controlled but it might all just be in my head However, I did notice a somewhat significant improvement in regards to the sound when hitting smaller bumps and cracks in the road... So it does seem to trigger the AMVAR actuators less frequently -

I guess they realised that the old setting was too sensitive - the suspension was trying to adapt to even the slightest road imperfection, but if the speed of the car was higher than let's say 30 mph, then the suspension had in fact no time to actually adapt, as by the time it reacted, the imperfection was already gone, so all the passengers were left with was the sound of the actuators piling up on top of the sound of the actual bump or crack, and that's something they seem to have fixed...

Will do more driving and report if I find anything else

Tue Jan 22 2013, 08:23pm
Joined: Sep 30 2012
Member No: #1044
Location: Bonn
Hi Sam,
thanks. I already had the C6 in two different garages which told me there were no update available. But of course they did not let me watch the procedure so I do not fully believe what they say if you know what I mean.
I persuaded my new diagbox/lexia to work properly today. Finally got rid of the obnoxious seat belt beeper hooray! I shall try to find the CSS software version number next time.
I'll stay in tune

P.S. the lexia tells me that the C6 has got 41 control computers to read. This is quite something.
Tue Jan 22 2013, 08:45pm
Joined: Jul 17 2012
Member No: #954
Location: Bergen
Thanks, this was useful. I can take it to my garage. Did you se the date of update for CSS(AMVAR) ?
Wed Jan 23 2013, 09:47am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
@Pappnase: yes, lots of computers, but those 5 are the mains which in term communicate with the others...

Now, my guess is that if the guys over at 2 different services told you that your car's CSS is up to date and the latest version is installed, then that must the case, and you can rest easy... I mean, it's such an easy and straightforward operation (it only took 2-3 minutes to do the update from start to finish, 30 seconds to find out if it needed the update or not), that it wouldn't make any sense for them to tell you that it doesn't need it if it actually did

@Tjensen: sorry, I didn't get the chance to see the date for the CSS update... I did see the SDI software version - it was dated 2011, which took me by surprise as I hadn't expected such a new version, seeing that my car was first registered in 2007, but is in fact a 2006 build...

However, I promise you that next time I'm at the service (which hopefully won't be too soon, if you know what I mean), I will ask the engineer to take screenshots of the Download Identification screens and, with Dave's help, post them on the website...

Fri Jan 25 2013, 09:40am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
Happy to announce that I had the privilege of having my first ride in a DS yesterday evening.

It was a DS19 Special with 1.9 Petrol engine dating from 1971 owned by Romanian fashion designer Florin Dobre...

The ride was magical, and even though it was cold and raining cats & dogs in Bucharest, I absolutely loooved it...

Having said that, I must admit that while the charm and nostalgia and happiness and excitement on my part were all of indescribable proportions, the rational side thought back to some earlier discussions we've had - analog vs. electronic - DS ride vs C6 ride and what I found was that instead of judging them one against the other, picking sides and scribbling mental lists of plus and minuses for each one, I just sat back in awe and began to appreciate them both even more than before... Although they are definitely not the same, it is clear to me now that they share the same beautifully engineered genetic material...

Sam out!
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