Non Hydroactive spheres on a hydroactive Xantia.

Quackers · Post by **Quackers** » 01 Jul 2006, 14:12

Are there any safety dangers with fitting non hydroactive spheres to a hydroactive car (left and right suspention) ? My local garage says he has always done this with his own Xantia as he finds hydroactive not as comfortable.

Whats the difference between the Hydro and non hydro spheres?

406 V6 · Post by **406 V6** » 01 Jul 2006, 14:34

HA spheres have lower pressure and stiffer damping respecting non-HA spheres.
If youput non-HA spheres on a HA car, the ride will be extremely soft, on the verge of safe behaviour by the car.
Not advisable to do.

Post by **Peter.N.** » 01 Jul 2006, 14:48

It depends on how you drive, if you corner hard, as 406 V6 says, it will make the car less stable. My XM is fitted with 'comfort' spheres which soften the suspension and as far as I am concerned the softer the better because I go in more for comfort than speed, but then I would still use cross ply tyres if they were available! So really its up to you, only you know your driving style.

AndersDK · Post by **AndersDK** » 01 Jul 2006, 15:05

Agree with Peter -

The older you are the more comfort you want. Just ask around how many people have a problem with their back

406 V6 · Post by **406 V6** » 01 Jul 2006, 16:42

The older you are the more comfort you want. Just ask around how many people have a problem with their back

Present! And i have back problems for 4 years now (i'm 26)

If you really want it to be more comfortable, i would check the pressure/damping differences between the HA and non-HA spheres. The one closer to your standard HA spheres should be picked, and use the car in sports mode just in case. With time, you may be able to discern the apropriate moments of having it in normal or sports mode, depending on your driving.

I, for instance, having a non-HA car, chose the closest spheres, i.e., the 1.8L version. Why? Because the pressure is the same (the car won't be harder/softer) but the damping holes/discs are larger. All in all, i feel what one feels when the car has softer dampers, increased lateral inclination of the car at front, but still controllable when i'm in a hurry. Ok, i sometimes get a bit aprehensive when driving above 130kms/h and hit a depression on the road

andmcit · Post by **andmcit** » 01 Jul 2006, 22:46

The way to crack this one on a hydractive car is play about with the CENTRE spheres first. You can open the diameter of the jet on the damping disc that's held into the housing for the centre spheres - this is easily removed once you've taken the trouble to take the centre sphere housing off the car and a competent hobyist or a professional machine shop can drill the metal disc to a wider diameter.

Guess you could of course renew the centre spheres as these NEVER get any attention and are practically ignored when it comes to sphere renewal - these boys do all the soft damping at the end of the day - the corners are there to supplement the centres and are the one's left to do the job when IT IS IN SPORT mode which we all will no doubt agree is something that is best left switched off!!

Andrew

andmcit · Post by **andmcit** » 01 Jul 2006, 22:55

One other thing to bear in mind here when you're jetting open the corner spheres by changing them for non standard spec ones is the stability of the front end under extreme emergency braking. Would you fancy extra wallow on the nose as you'll effectively have more fluid movement before the front end tautens up helping the grip - could just make THAT difference to stopping distance before that Que of stationary traffic on the motorway of that bloody big tree!

IT'S ALL ABOUT COMPOSURE - Citroen didn't just randomly pluck any old sphere out of the cupboard when it came to selecting specific spheres for each engine variation [weight] in a particular model range...

Jetting out from .7 to 1.1 is effectively increasing the real cross sectional area of fluid flow by a massive margin. Why didn't Citroen do it that way in the first place!?

Andrew

Quackers · Post by **Quackers** » 01 Jul 2006, 23:03

So its not advisable then to do since this since my Hydroactive car also has Activa too

and i do like to "corner harsh".

andmcit · Post by **andmcit** » 01 Jul 2006, 23:11

Quackers wrote:So its not advisable then to do since this since my Hydroactive car also has Activa too and i do like to "corner harsh".

I'd definitely leave it as nature intended! Make the effort to get the centres done to optimum health and the corners will still have the tautness on top of the anti roll rams that'll help the composure of the whole set up around the bendies!

Andrew

Mandrake · Post by **Mandrake** » 01 Jul 2006, 23:19

I'm surprised to see people trying to make Hydractive 2 even softer....

In my opinion the springing/damping rate in the soft mode is already very soft, what is more likely is that the ride is harder/harsher than it should be for reasons other than sphere pressure and damper adjustments, eg -

* Air getting into the hydraulic system due to a dodgy pump inlet hose or a dodgy pump - the effect is to make the suspension "crash" harshly over broken surfaces such as manhole covers, potholes, curb etc... (Believe me, even a modest air leak can totally ruin the ride quality and make it feel like you're riding in a golf cart

)

* Front suspension strut bushes/shaft badly worn - this manifests itself in a number of ways - struts sticking/binding during cornering or braking, (ride gets a lot harsher and more fidgety during cornering etc)

Unusual sensitivity to ride height, (ride quality varies from good to poor with just 10-20mm difference in ride height due to "wear patches" on the strut shaft that cause binding points at specific heights)

A general sense of "harshness" and lack of isolation from the road despite all spheres being in order and no other problems being found...

* Rear suspension arm bearings - similar harshness effect to worn front suspension strut bushes, except not ride height sensitive. (Since its a rotating bearing)

* Hydractive system fault causing excessive use of the hard mode. (Sensor fault, such as speed sensor, or perhaps even stuck in the hard mode permanently etc...)

* Normal mechanical problems such as worn balljoints and rubber bushes.

Although putting on spheres with softer damping can seem to improve the ride when one of the above problems exists, it's not the real answer.

Out of those 4 problems I've had the first two - air leaks (still working to fix that one...

) and strut shaft/bush wear.

If you search the forum you'll find some pictures I posted of the wear on the strut shafts where it had worn through the plating/hardening, and since replacing them I notice the ride quality is no longer extremely height sensitive, the ride doesn't get all harsh and fidgety around corners, and it just feels smoother in general.

(In fact the ride at the front went from feeling harsh and excessively damped to the point where its almost too soft and floaty at the front now - with the same correct spheres)

If anything, I've found a need to INCREASE the damping in soft mode a bit, after I find and fix these other problems....(by reducing the 1.1mm bypass hole in the centre damping valves to about 0.9mm)

So I would suggest that people that find Hydractive 2 rides "harshly" with the correct spheres types fitted and in good condition really ought to be finding out what the real problem is rather than redesigning the suspension tuning by changing all the sphere types

Regards,
Simon