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C6 Suspension 'Pitching'

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Tjensen   
Fri Jan 25 2013, 01:22pm
Joined: Jul 17 2012
Member No: #954
Location: Bergen
Intersting experience you had. My DS experiences are old (sold my last in 1998). DS had beautiful comfort and stability, as well as an abilty to forgive drama and errors in the driving situation. And it had consistent handling. But nose-heavy and with (predictable) limits. XM Hydractive and even more C6 are less extreme and more like other cars in some ways (wheel geometry ?), but with comfort, precision and especially adaptive properties that are unique and better than all other cars (?). Makes it a safe and relaxed car to drive. But I miss the DIRAVI steering of the CX and XM V6, better than both C6 and DS.
magcar   
Thu Jan 31 2013, 09:02am
Joined: Oct 22 2012
Member No: #1066
Location: Kungsbacka
Hi Sam,
Is the update service from the Citroen garage free, or did you have to pay for it?
smihaialex   
Thu Jan 31 2013, 10:26am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
Hi Magcar,

I had to pay for the time of the engineer doing the job, not the update itself - it was the same price as doing a computer diagnosis - less than 50 quid

Sam
Lars of Sweden   
Sat Feb 02 2013, 04:56am
Joined: Aug 17 2012
Member No: #991
Location: Tenhult
magcar wrote ...

Hi Sam,
Is the update service from the Citroen garage free, or did you have to pay for it?

At "my" garage, they update the firmware (if applicable) at time of service. No extra charge!
Tjensen   
Sun Feb 03 2013, 02:34am
Joined: Jul 17 2012
Member No: #954
Location: Bergen
Tried the "sport" gearchange and pressed the pedal today. Under heavy acceleration the steering is changed and have a bit of its own life. This behavior is like "all" powerful front-wheel drive cars, but not DS and not CX and not XM V6. Is it too much power or just "industry standard" sloppy engineering ?
pclark   
Sun Feb 03 2013, 11:08am
Joined: Oct 08 2009
Member No: #3
Location: North Yorkshire
Torque steer is inevitable in a front wheel drive car with so much power and torque, Unless it had true centre point steering like the DS and CX, but they had much less power and particularly torque (apart from the CX Gti Turbo) anyway. The V6 HDI is at the limit of what front drive can handle, thats why more powerful cars are rear or four wheel drive.

Some very powerful hot hatches such as the Ford Focus RS and the Top Astra and Megane have the steering joints outboard of the front strut to get the steering axis nearer to the wheel centre line to reduce torque steer (rather than using the strut itself as the steering axis in conventional Macpherson strut cars).

The C6 (and C5, Peugeot 407 and top versions of the 508) with the double wishbone front suspension acheive similar results, but not true centre point steering that was a Citroen feature when they were an engineering led firm before Peugeot's accountants got involved!

Having said that Citroen probably would have gone bust many years ago if they hadn't!
Tjensen   
Sun Feb 03 2013, 11:17am
Joined: Jul 17 2012
Member No: #954
Location: Bergen
My CX was the Turbo and the power/weight ratio was at the same level as C6 with better acceleration figures So it can be done. But: not really a problem, and better than most. Thanks for information !
smihaialex   
Mon Feb 04 2013, 09:07am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
I agree, power steering is there, especially if you drive a bit more aggressively, but is still very well controlled in the C6...

The Mazda 3 MPS and the VAUXHALL Vectra OPC are in my opinion the worst in this category - their chassis and steering was just not engineered to handle all that power - they are the only 2 cars in which even the driver can get motion sickness, while driving

And no, having 4 wheel traction or rear wheel traction does not help...

With most modern automatic 4x4 transmission design, when driving on a decent road, the car is basically front-wheel drive - only on poor or slippery roads, the ratio can become as much as 50-50 (50% of the traction on the front wheels, 50% on the rear wheels), although for most cars it is actually 60-40.

And with rear wheel drive, there is indeed no actual power steering, but the back can get away from you which is actually worse than power steering I say that because you immediately feel power steering and can correct it by naturally taking your foot off the gas, but with your back flipping, it's not as easy, because taking your foot off the gas might actually make the car spin

Sam
Tjensen   
Mon Feb 04 2013, 09:20am
Joined: Jul 17 2012
Member No: #954
Location: Bergen
The CX (the last Citroen to be designed by the magical Citroen research & development division (put down in 1982)had almost no power steer, not even in the Turbo 0-100 7,9 sec 168HP 40,5 kg/m torque. CX did not have true center-point steering, and did not have center-mounted brakes, So it can be done... But I agree the C6 probably are among the best in this aspect today. The XM had no version with really high torque and was smooth in this area. But I have not tried the XM 200 HP V6-24 or the Citroen V6 SM.
smihaialex   
Mon Feb 04 2013, 09:54am
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
I bet the SM was something else

Sam
ChrisHunter   
Sun Dec 01 2013, 06:09pm
Joined: Jul 20 2010
Member No: #188
Location: Lancashire
flat-out on the motorway, in our first CX, once, we had the front-right go flat just as we were passing a long gaggle of lorries, occupying both inner lanes - we had a car behind us, so we had to continue for a mile or more before we could get far enough ahead to slow & transit safely to the hard shoulder ...

the tyre was wrecked, but it was a completely drama-free experience ...

changing the wheel, on the hard shoulder, was also (of course) pretty painless - worst part was the lorries going-by while we were doing it - a bit close, blowing us about, and rocking the car !
simonpj   
Sat Apr 26 2014, 01:18pm
Joined: Mar 17 2014
Member No: #1631
Location: Cambridge
This was one of the threads I read after buying my C6 a month ago, to try to figure out whether its suspension was performing as intended - so I thought I'd add my experience.

I've now had both front spheres replaced. The ones on the car when I bought it (built 2006, 39,000 miles) were at 41 bar and 44 bar (compared to the specified 50 bar). Though the suspension seemed to be ok at speeds over 25mph, I was aware of needing to drive quite deliberately around town in order to minimise pitching - especially over speed bumps, where the car definitely seemed to want to nose dive and rebound off the back edge of the bump, sometimes accompanied by a clonk as the suspension travel bottomed out. The car was also bouncing backwards slightly after coming to a full stop on the brakes - which seemed a clear indication of insufficient damping.

Before I'd had the sphere pressures checked by B L Autos I had no idea whether the suspension characteristics I was seeing were just the way the C6 suspension works, or whether they were signs of a problem. My previous experience of the DS, BX, CX and XM didn't help, as the C6 suspension is clearly quite different. Reading the various threads here made me wonder whether the car's suspension software was up to date. B L Autos confirmed that it was - so any problems were just down to the under-pressure front spheres.

With the new spheres now fitted the pitching is very much reduced. The front end feels adequately damped and there's no need to drive deliberately over speed bumps and bad town street surfaces to avoid pitching. One other distinctive C6 suspension characteristic - the rapid rocking from side to side that can be caused by irregular surfaces and steep camber on B roads between about 45 and 65 mph - also seems to be reduced.

I'm glad to have been able to diagnose that the suspension wasn't working as intended, with the help of this forum, and B L Autos. And very happy to have it working well now. Having come from a car with a radically different type of suspension - a BMW 540i M-Sport which is very low and very stiff - I was quite ready for the C6 to have very different strengths and some real weaknesses by comparison. But I'm actually really surprised at how well the C6 does at hustling quickly along B roads - even though I never resort to the Sport setting on the suspension. I'll post a longer comparison of the C6 and the 540i in a separate thread.

Simon

ChrisHunter   
Sat Apr 26 2014, 07:38pm
Joined: Jul 20 2010
Member No: #188
Location: Lancashire
we found early-on that the sport setting usefully reduced response to blustery cross-winds on the motorway ...

otherwise, we didn't like it much ... at least, that was until we'd got really familiar with the car, then we appreciated it more - both suspension & engine sport settings ...

as you say, the car s really good on B-roads, and can be hustled along remarkably quickly - and all the more so, in sport mode, when the hang of it is got !

wasted   
Mon Aug 11 2014, 12:00pm
Joined: Feb 12 2012
Member No: #799
Location: Cambridge
My local Citroen garage keep trying to tell me that my suspension feel is normal and the software is up-to-date. In frustration, I bought an ebay lexia device and had a play at the weekend. I corrected my ride height as it was out of spec front and rear. It has helped with low speed feel, but I still get some weird, back and forward pitching when on the motorway. I really want to rule out software side of things before starting on the mechanical bits.

Can anyone confirm the version, and/or date, of the CSS software update that is supposed to fix this? I need some ammunition to persuade them to actually do something.

Mine is version 104.112 and issued 08/12/2006.
Tjensen   
Mon Aug 11 2014, 02:41pm
Joined: Jul 17 2012
Member No: #954
Location: Bergen
I thought the AMVAR/CSS had serious updates after 2008 and now should be a 2011 version.

But I have litttle information on the AMVAR history. Is at a PSA in-house design ? Any other uses of the system ?
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