Differance between hydractive and hydroneumatic spheres ??

XantiaDaveEire · Unread post by **XantiaDaveEire** » 25 Oct 2009, 12:41

My new Xantia deserves a change of spheres as the car is very hard and does not take ramps or speed bumps very well compared to my other xantia where you dont even notice them..but back to the topic as money is tight iv been looking on ebay and im not too sure as to the differance between hydractive spheres and hydroneumatic spheres,could anyone shed a little light on whether it makes a differance by what spheres are fitted by brand name,front spheres on the rear etc

andmcit · Unread post by **andmcit** » 25 Oct 2009, 12:53

There will be a significant difference in the spheres between the conventional
hydropneumatic and the more sophisticated computer controlled hydractive
system and it will have a real difference to the way your car rides if you don't
use the correct spheres to the point where it could even endanger driving the
car. Whilst they all appear to be the same size (ie. sphere volume - usually
500), their pressures and more critically the opening aperture or "jet" will
dictate the volume flow of LHM under pressure into the sphere and against
the diaphram.

The usual AMTEC ones from GSF seem universally liked and reliable and there's
always an element of doubt and debate on the longevity and effectiveness of
genuine new old stock Citroen ones sold on ebay.

If your car is hydractive (Exclusive/VSX) it may very well pay to consider
changing the middle spheres on each axle first as these give the car's ride
the compliancy and subtlety in the normal mode rather than alter the easier
but less contributory corner ones.

Andrew

Unread post by **CitroJim** » 25 Oct 2009, 12:58

Andrew, I was about to post and I saw you had already said the same as I intended

Just to add though, never use hydractive corner spheres on a non-hydractive car. It will be HARD and incorrectly damped.

The reverse though is quite acceptable. Non-Hydractive corners on a Hydractive car gives a softer ride all-round although at the expense of some roll and wallowiness on hard cornering.

XantiaDaveEire · Unread post by **XantiaDaveEire** » 25 Oct 2009, 13:02

thanks andrew

the spheres in question were amtex..so il probably go for them

Unread post by **Old-Guy** » 25 Oct 2009, 14:08

Make sure you get the correct spheres for the particular model!
When the sphere table went missing some time ago from GSF's website, I made it available on my Xantia web page

deian · Unread post by **deian** » 25 Oct 2009, 15:13

Old-Guy wrote:Make sure you get the correct spheres for the particular model!
When the sphere table went missing some time ago from GSF's website, I made it available on my Xantia web page

That site of yours is a godsend for us xantia owners!

andmcit · Unread post by **andmcit** » 25 Oct 2009, 15:24

Good site for critical relevant info Old-Guy; why not have a permanent link
to it in your signature so it can be seen in every post you make?

Andrew

Unread post by **Old-Guy** » 25 Oct 2009, 15:33

Andrew,

Why didn't I think of that?

I'll do it now.

Guy

Unread post by **CitroJim** » 25 Oct 2009, 16:08

Guy, you have done an incredibly useful and valuable set of web pages

It deserves much wider circulation

Unread post by **Old-Guy** » 25 Oct 2009, 16:10

Jim

You're too kind.

Guy

red_dwarfers · Unread post by **red_dwarfers** » 25 Oct 2009, 19:05

I've had your page booked marked for some time Guy, very useful If I want to quickly get to some core information rather than trawling through the FCF.
I believe at the Stratford rally this year we consulted 'the Old-Guy pages' to look at a sphere pressure table via mobile interweb