Normal/Sport suspension - XM query

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Robin
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Normal/Sport suspension - XM query

Post by Robin »

Hi all, in words of few syllables can someone explain what happens when you change from Normal to Sport?
Are there a number of electro valves or just one and where would I look for them?
I am uncertain whether the system is operating correctly. I do notice a change in the suspension, cats eyes feel like the whole cat in sport yet there is a definate firmness to the whole car always.
This firmness seems more from the rear than anywhere. Certain road surfaces can make everything rattle. It's not the spheres, all checked and or replaced this year by Pleaides.
It is the 2.5 estate, registered 98.
Cheers all, Robin
tonespeed1999
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Post by tonespeed1999 »

from what i can remember from reading the citroen technical bulletins years ago,first the sports setting becomes active when your speed exceeds 20 mph,it was claimed by citroen that the XM could take a corner upto 15 mph faster than a CX.the system wasnt very reliable on early models,as the computer kept switching it self between auto and sport.in one of the technical bulletins they recommended that all the earthing terminals were replaced on the inner wings with eye connectors.sometimes this was enough to cure many of the engine and suspension faults.
JackTar
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Post by JackTar »

Sport mode isolates the centre spheres. Even in normal mode the ECU will switch to sport mode when it thinks its necessary, like on corners, braking or accelerating so there is little point in setting it to Sport. It sounds like yours is working ok, the XM is quite firm but should still be comfortable. It depends what you compare it with.
Jim
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Post by Mosser »

If its working properly it will be difficult to tell the difference between the 2 modes, i kept playing with it for the 300,000 miles i drove in mine and was never sure whether i could tell the difference or not, but the garage always insisted that it was working as they plugged their diagnostic computer into it and took it for a run and watched the valves closing and opening just like they should have done
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Post by Robin »

Many thanks all.
Well, if it ain't broke I ain't playing with it!
I am just a little concerned about the roughness though from the rear. On some surfaces it does rattle the contents of the door pockets and shake the back about a bit. I am comparing it with my Xantia - is this a good thing I wonder?
Both the Hc's work properly as do the Acc spheres - I do like watching it level out after filling it with fuel, the amusment helps with the £60 bill a bit[:(!] and the tyre pressures are correct. It is on Pilots, I just wonder if a different tyre could soften those jarring little bits. It otherwise rides like a dream on the motorways. Which reminds me, I think I may just have a rear wheel bearing beginning to sing a little but all feels OK when I spin the wheel at present.
Again thanks lads, Robin
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Post by RichardW »

A 98 will be fitted with Hydractive 2, which means the hydractive is always 'on' - putting it in sport mode just makes it easier to provoke it into hard mode. You should be able to hear the electrovalves energising (they hum) when you open a door to the car, as the non-energised state is 'hard' and energised is soft, and it switches to soft when a door is opened. I think you should be able to feel the difference - the centre spheres are quite soft, so test the suspension after it's been stood a while by bouncing it, then open a door and do it again to see if it's gone softer.
I am not sure my 97 Xantia with hydractive is working properly, but the ride is certainly more 'controlled' than my previous non-hydractive Xantia - much less pronounced wallow over 'difficult' corners.
Mosser
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Post by Mosser »

I dont know if the estate is different, but my XM was a saloon 2.5td exclusive with hydractive 2 and you shouldnt be able to feel any bumps at all, and there certainly shouldnt be anything moving in the door pockets,
My XM was the smoothest car i have ever been in and it would soak up 99% of all bumps and speedhumps without you knowing it had done it
Robin
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Post by Robin »

OK then, time for a bit more investigation. It is certainly harder than my Xantia over smaller ripples and bumps but wonderful on the motorways and better roads.
What am I looking for by way of valves? Robin
skwuddles
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Post by skwuddles »

Try fitting XM comfort spheres , I fitted them to my Xantia , and it is now as soft and comfortable as my old BX [:)]...... and when I activate the (sport mode ) .... It stiffens up to the old "standard" setting !!... which I personaly find far too hard !![V]
Robin
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Post by Robin »

Skwuddles, now there's a thought! Robin
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Post by Homer »

The general consensus on "comfort" spheres is don't do it.
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Post by pete_wood_uk »

Robin, like you I'm learning my way round Hydractive II at the moment, in my case on a Xantia estate, but I think that the principles are pretty much the same. I have the opposite problem to you - my back end is willowy soft, but the front is not quite as I suspect it ought to be. Which suggests that both of us might have a dodgy sphere or two :-).
As Richard says above, you can benchtest this in quiet garage. The way mine works is - unlock the car and open a door, and it starts whistling gently, which is the sign that the solenoids are open and all 3 spheres in circuit at each end. It should be willowy soft. Lock it up again, and wait for a timeout, then you'll hear a click as the solenoids go off and lock out the centre sphere and the side/side interconnect. It's now in "hard" mode, and should be a lot firmer, but not solid, at each corner. You can now go round each corner as you would with a "normal" Cit and do the bounce test at each corner to see if one corner or end is different from the others, to see if you've got a shot sphere or not.
As far as I can see, if it's softish in "soft" but solid in hard, then a corner sphere has gone; whereas if there isn't much difference at one end between soft and hard then a centre sphere is on the way out.
This is what I've worked out from first principles and the hydraulic diagram. I could be 100% wrong, always a danger of applying engineering skills in an area where you know nothing :-).
When I'm in a hurry, I occasionally push the "in a hurry" button and I do find that the car responds better in the bendy bits, albeit with noticeably worse ride. But you have to push it much harder than I habitually would, it's really only noticeable when I'm trying to "make progress". God knows when it would switch in if left in soft mode, presumably by French standards I must drive like a complete wuss.
Pete
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