C5 2009 excl. suspension - how to check?

[The Ace]

From what I have read so far, indeed the "Sport" button sets the various thesholds for switching to "sport" mode a bit lower, showing the system that the driver "prefers" the sport over the comfort mode. It will still switch back to "comfort" settings if it detects that you are cruising casually, generally laying off the go-pedal and/or not thrashing the steering wheel left and right. Not to mention that I've read somewhere that the car switches to "sport" much easier/sooner at highway speeds. In general, it seems not even Citroen themselves can answer this question thoroughly

That's why I'm asking whether there is a bullet-proof way to test whether the system works as it should, without starting to replace spheres and/or dampers....

[GiveMeABreak]

I can definately say that on my X7 it does make a significant and instant difference when activating the Sport mode Richard. We have meandering winding roads on the way to town and it is almost routine now to switch to Sport mode on the same part of the journey every week. The car instantly stops left and righ pitching and corners almost without any roll. Switching this back turns it off instantly. It is very noticeable and don't forget that the X7 has 7 spheres so should be more noticeable when you disengage 3 of them.

[xantia_v6]

I have no experience of HA3+, but with the old HA2 system, I found the best demonstration of the system switching is to find a really quiet straight country road (where there is no audience and no chance of being surprised by other traffic), drive at about 35 MPH in normal mode, and perform an imaginary slalom along the centre line increasing the frequency of the swerves until you can feel the body roll each way, then while still slaloming, hit the sport button and feel the difference.

[white exec]

Finally, Richard has made the essential point. Hydractive II, 3 and 3+ all operate in this similar manner - the thresholds at which the suspension 'goes firm' are changed (generally lowered, so it goes into firm more readily).

To get the suspension into firm mode, you will need to drive either
- at 24km/h or more (iirc); it won't go firm while stationary
- with significant or rapid movement of the steering wheel
- with large or rapid movements of the throttle pedal
- with a greater amount of body movement or roll
- encountering a large change in road level
- by applying the brakes hard
...

It's all explained here (essential reading for any hpn Citroen owner):
http://www.citroenkerho.fi/xantia/pdf/t ... kaopas.pdf

Only Hydractive I puts the system into 'permanent firm' by simply operating the mode switch.

[The Ace]

Excellent document !!!!

[Paul-R]

Indeed. Saved and printed.

[GiveMeABreak]

Yes, I've seen this previously, it is a very informative article and was probably written before the X7 was released, which after all is a different vehicle in many regards to the previous C5, using the running gear from the C6 for one, and the additional spheres. To quote from a Citroen press release 'Hydractive 3 Plus and metallic suspensions comprise a double wishbone and linked hub carrier at the front and a multilink set-up at the rear with a drop-link longitudinal arm', which improves the balance between the steering and damping over the previous models.

As mentioned by Richard, the fimness settings are governed by the driving conditions and vehicle data as outlined above and in Gabor's document, and use a set of laws to change between the 'soft' and 'firm' modes. But, activating the Sport mode button manually deactivates the 'sportiness coefficient calculation' module as detailed below and 'forces' the max. settings of the Sport map. In other words you get the 'dynamic driving style' or as Citroen marketing says:

"Of course, if you really want to experience something unique, you can opt for the Hydractive 3+ suspension, our most advanced system to date. This advanced technology offers a whole new standard of luxurious driving, or at a touch of the ‘sport mode’ button, the ultimate in driving excitement".

Extract from the technical documentation:
When the "Sport" mode is selected, the decision thresholds are lowered.
N.B. : The "sport" mode can be "forced" by pressing the "sport" mode button, or can be determined by the system in relation to the style of driving.

In "soft" mode, the values of the "soft" mode map are multiplied by a weighting coefficient of less than 1.
The more "sporty" the style of driving, the more the "sportiness" coefficient decreases and the lower the thresholds used.
In "sport" mode, the "sportiness coefficient calculation" module is deactivated.
The "sportiness" coefficient is forced to the maximum "sportiness" value associated with the "sport" map.

So in other words you get the maximum sport effect when using the manual switch.

The system does a good job overall, but on really windy roads it does not firm up sufficiently using the standard suspension setting - if it did there wouldn't be a need for the sport mode and to be honest if that setting wasn't there, I'd reluctantly have to consider a different vehicle for the rural mountainous area where we live at present as we'd all end up sea sick!

[xantia_v6]

So in other words you get the maximum sport effect when using the manual switch.

But note that that is not the same thing as getting firm mode, as you did with HA1.

[The Ace]

Indeed, it is mentioned quite a few times in this document, in HA3+ the "Sport" button lowers the various thesholds, making it more easy to switch to "Firm" and to stay in this mode "easier" and for longer. Which is quite different behaviour than HA1 (which was practically on/off), and more elaborate than HA2. And since HA3+ and C5 are mentioned throughout the document, and especially C5's advanced electronics, I'm guessing it must have been written mid-00's ?

[RichardW]

Extract from the technical documentation:
When the "Sport" mode is selected, the decision thresholds are lowered.
N.B. : The "sport" mode can be "forced" by pressing the "sport" mode button, or can be determined by the system in relation to the style of driving.

In "soft" mode, the values of the "soft" mode map are multiplied by a weighting coefficient of less than 1.
The more "sporty" the style of driving, the more the "sportiness" coefficient decreases and the lower the thresholds used.
In "sport" mode, the "sportiness coefficient calculation" module is deactivated.
The "sportiness" coefficient is forced to the maximum "sportiness" value associated with the "sport" map.

So in other words you get the maximum sport effect when using the manual switch.

The system does a good job overall, but on really windy roads it does not firm up sufficiently using the standard suspension setting - if it did there wouldn't be a need for the sport mode and to be honest if that setting wasn't there, I'd reluctantly have to consider a different vehicle for the rural mountainous area where we live at present as we'd all end up sea sick!

Reading too much into the marketing bumff....???? The fact that they didn't call it Hyd 4 suggests it is very similar (at least physically) to that fitted to the MK1 / 2 C5 - which also have 3 spheres / axle. AFAIK there are only 2 settings, hard or soft - but the words above suggest that the map is not fixed in comfort mode as to when it switches to hard mode, but is modified depending on driving style. Sport mode just applies the lowest thresholds. So, it doesn't get any stiffer in sport than comfort, it just gets there sooner.

[Mandrake]

Does the C5 X7 not use the Amvar system of the C6 ? If so there are a lot more graduations in damping than just hard or soft of Hydractive 2...

[RichardW]

Dunno...if so I hang my head in shame and slink off to the corner, and you can ignore everything I have said on the matter....

[white exec]

. . . So, it doesn't get any stiffer in sport than comfort, it just gets there sooner.

Precisely.

In original Hydractive, two switch positions: "Auto" and "Sport"
In Auto, driving is in Soft Mode, unless sensors switch it into Firm. Car will shift between Soft and Firm depending on road conditions, and how it is driven.
In Sport, the system is forced into Firm Mode, and remains there until put back to Auto.

In Hydractive II (introduced RP5929, Feb.'93), two switch positions: "Normal" and "Sport"
In Normal, as per Auto above.
In Sport, car will start off and remain in Soft Mode, until driving conditions/style shift it into Firm. It is not locked into Firm, although the thresholds where it goes Firm are changed to a second set of parameters. In general, it goes into Firm more readily, and stays there for longer. Undramatic driving on a good road sees the suspension revert to Soft.

Original Hydractive (often now tagged HA 1) and HA II both used three spheres per axle in the suspension department.
HA 3 offered a simpler system, with just two spheres per axle.
HA 3+ built on HA II, but added height control (ground clearance) linked to vehicle speed and road condition.

[Paul-R]

HA 3 offered a simpler system, with just two spheres per axle.
HA 3+ built on HA II, but added height control (ground clearance) linked to vehicle speed and road condition.

I thought that the speed controlled height control (lowered at high speed, raised a little bit on slow bumpy roads) was also on the HA3. I don't have my early handbook to hand but memory thinks so.

[GiveMeABreak]

Does the C5 X7 not use the Amvar system of the C6 ? If so there are a lot more graduations in damping than just hard or soft of Hydractive 2...

No the AMVAR system was not used on the C5. On X7 V6 Engines there are height sensors on each corner as opposed to the Front and Rear axle on the other Hydractive models. On these models the suspension settings are calculated using these four sensors and have a variable shock absorber suspension computer (CSS) - but without the AMVAR variable damping function. The CSS computer is used for the power steering and body height sensors only.