Wrong Sphere - Will It Cause Problems?

I've a spare front HA sphere that's barely used so I was thinking of trying it in place of the existing old accumulator sphere. The capacity is greater and the pressure is higher so I suppose the pump will have to work a bit harder but I can't see why it would cause any problems.

Any comments?

Steve.

Assuming that the opening (orifice) of the two spheres is similar, the problem might lie with the volume of LHM available from the accumulator, within its (ideal) operating pressures of 145 to 170 bar.

1// A 400cc 62 bar accu sphere will store:

171cc of LHM at 140bar [145:62=2.33 => 400:2.33=171cc]
141cc at 170 bar.

So 171-141=30cc LHM available between cycles.

2// A 500cc 70bar hydractive sphere will store:

241cc at 145bar
206cc at 170bar

So 241-206=35cc

So yes the pump will need to supply more each time between the pressure regulator's cut-ins and cut-outs if u use the hydractive sphere. Doesn't sound a terrible difference but who knows...But u will also have longer cycling times (by 16%). The other thing to be said is that with the 500cc sphere, pressure drop as LHM is being dispensed will be slower. I can only think this sounds good. But who knows, again...Why Cit sticks to a 400cc 62bar accu for all its models?

Why don't u try it and tell us??

cheers
George

Nice bit of maths there.

Yes I think I will. I was going to do it tonight but the dark nights are taking their toll already! Maybe tomorrow and I'll report back.

Maybe Citroen didn't do it because it could cost more to make a 500cc sphere. Only pennies I know but that's how car companies think isn't it?

Steve.

This afternoon I removed the regulator stripped it, cleaned it and re-assembled it correctly(!) with a couple of extra shims to up the pressure. It doesn't leak anymore (well it was a bit sweaty) and the ride is exactly the same. I couldn't find my spare front HA sphere I was going to try so I put the existing one back on.

Front hydractive valve next. Compared to the Xantia this looks like access is awkward.

Just as a question for any estate owner out there, how much travel do you get at the front bumper if you give it a reasonable push when it's in soft mode?

Steve.

Steve

be careful what u do with pressures -the high one specially-, on mine I had set this at 177 bar and 2-3 months later my front e-valve was leaking at the valve closing (not at sealed parts). I had looked this e-valve before and it was not leaking at all (car at drive height, engine running). Not saying that it was the higher than nominal pressure that destroyed it, but cannot think of any other reason as well. In my case as well, the added pressure did not make a difference (had it at nominal 170bar before that). I quickly put it back at 170 and bought a new e-valve...

cheers
George

Looked very straightforward to me -removal included- but then don't know how a Xantia is.
G

Looked very straightforward to me -removal included- but then don't know how a Xantia is.
G

Sorry, did not realise, do u refer to the electric-valve or the hydractive valve proper (the one that actually cuts the middle sphere off circuit)?
G

I'm going to remove the whole valve block, I can then remove the electro valve on the bench. I'm wondering if I'll ever get the suspension as it should be. I did all this to the Xantia and that was never consistently good. On a Xantia the HA valve block is just behind the radiator at the bottom left, pretty much where the pressure regulator is on an XM.

Steve.