Comfort spheres for Xantia V6 ?

[Mandrake]

Does anyone know if there are "comfort" spheres available for the Xantia V6 ? And if so by who ? (IFHS hopefully)

Since the front spheres are different from all other Hydractive 2 models I don't think the "standard" comfort spheres could be used...

Anyone tried them on a V6 ? People following my blog will know that I need a full set of spheres for my new V6 and I have to say I'm tempted to try comfort spheres for the first time, provided that it doesn't sacrifice the handling too much in sport mode or make it too floaty... A little bit better ride over potholes would certainly be appreciated, as there are more potholes than flat pieces of road in this area!

Should I give them a try, or bad idea ? I guess if I don't like them I only have to change the four strut spheres to go back to standard...

[Peter.N.]

For a really superb ride use accumulator spheres on each corner but if you want it to corner with it upright I am sure any other hydractive spheres would give you a better ride. The comfort spheres have a slightly larger diameter hole in them thus allowing more rapid fluid transfer. You could use non hydractive spheres and drive in sport mode you would them have the option of a soft or very soft ride.

Peter

[Northern_Mike]

Jim put something non-standard on the back of the Xantia Exclusive HDI we both owned. He'll tell you what they were. It rode very well. It did not handle...At all.

I'm just a grumpy Northern git.

[Mandrake]

That's what I'm afraid of Mike. I spent some time last night trawling the forum and found a number of posts from V6 owners who have tried it saying "don't do it!" and "made it handle like a boat". I do like to nip around corners so I guess its standard spheres for me then...

[Hell Razor5543]

I agree. Whilst Citroen don't always get it right, they do know the hydro-pneumatic system better than any other car manufacturer (having over 60 years of experience), and will have done their best to balance the system to the car. It is just a shame they appear to be dumping the system (the bl00dy fools!).

[xantos]

Well I have read somewhere that you put the centre (hydractive) spheres that have more pressure than the standard ones. It should give a more smooth ride and when you need handling the centre spheres get shut out and it becomes stiff, so you don't loose any of its handling...

[Northern_Mike]

You can indeed Xantos, but I think this would be something you could only do if you had your own kit to pressurise the spheres to your own taste or took a guess and asked Pleiades to do you some with different pressures..

I'm just a grumpy Northern git.

[xantos]

Indeed. And I have it!

http://www.frenchcarforum.co.uk/forum/v ... &start=105" onclick="window.open(this.href);return false;

[Northern_Mike]

It is just a shame they appear to be dumping the system (the bl00dy fools!).

The reputation it got as being awkward, leaky and unreliable 40 years ago was the death knell for it. It's been a long slow death!


I'm just a grumpy Northern git.

[Mandrake]

The rear Hydractive sphere is easy - fit a 62 bar accumulator instead of the correct 50 bar - they're otherwise identical. This is roughly a 20% softer springing rate.

I did that on my first Xantia for a few weeks while I waited for the correct sphere to come. The ride was a lot softer at the rear, but to the point that the squat under acceleration was a bit excessive.

Finding a higher than normal pressure front Hydractive sphere is difficult though - 75 bars is already the highest pressure spheres made, certainly without a damper valve. So you would need to custom gas it yourself and IMHO you wouldn't want to go any higher than about 85 bar.

[xantos]

Indeed. And I have it!

http://www.frenchcarforum.co.uk/forum/v ... &start=105" onclick="window.open(this.href);return false;

Have you used it yet?

No I haven't. Intend to this week.

Question. How much can you overfill spheres that have designated pressure let's say 35 bar? Can you fill it to 70 bar? If they all have the same membrane it shouldn't be a problem...

[Mandrake]

Question. How much can you overfill spheres that have designated pressure let's say 35 bar? Can you fill it to 70 bar? If they all have the same membrane it shouldn't be a problem...

The membranes should be the same, however I would not fill a sphere more than about 20% higher than what it should be otherwise the change to the suspension characteristics will be excessive, possibly to the point of being unsafe to drive at speed.

For the front hydractive sphere you have an additional concern - it's already charged to 75 bars, 20% higher than that is 90 bars - the problem with going that high is that when unladen there is only about 100-110 bars of oil pressure in the front suspension, so you are dangerously close to bottoming out the diaphragm of the sphere on the extension stroke of the suspension, limiting suspension travel abruptly and quite possibly doing serious damage to the diaphragm.

Hence my suggestion of not going higher than about 85 bars on that sphere. You don't have the same worry with the rear suspension because the unladen oil pressure is still about 90 bars and the sphere is only 50 bars - so 62 bars (which is 24% softer) still has a safe margin without bottoming the diaphragm. (And I've actually tried it before so I know it's ok)

[xantos]

The membranes should be the same, however I would not fill a sphere more than about 20% higher than what it should be otherwise the change to the suspension characteristics will be excessive, possibly to the point of being unsafe to drive at speed.

I'm just interested in this if I have a sphere that has ripped membrane I can use another one that is ok and then just fill it to whatever pressure I need. I intend to overpressure all spheres for about +5 bar, the rear struts spheres to 45bar (as CitroJim suggests) and centre (hydractive spheres) to about +10bar so that should be ok.

[Mandrake]

You can't just fill any sphere to your desired pressure - different spheres for different purposes (front, rear, different models of car etc) have very different damper valve tuning, and you can't change the damper valve. (At most you can drill out or reduce the centre bypass hole slightly to fine tune it but you can't change the leaf valves which set the damping threshold and control most of the damping)

So you couldn't just take a 30 bar rear strut sphere, fill it up to 45 bars and then fit it to a front strut - the damping would be all wrong. So if you're experimenting with increased gas pressure it needs to be the correct sphere off the correct part of the car...

[xantos]

Ohhh right I forgot about that... Thank you for remembering me! Well I would have remembered when taking the spheres of. Of course I would...