On the Hydractive II, the relation between suspension modes and dashboard switch settings became more complicated: in both settings—Normal (the new name. A stylish 2 piece designed to keep you cool when you’re working hard. Featuring a breathable mesh panel for ventilation, the HydrActive 2. Well Ive been doing some more research.. And I have been reading about the Xantia VSX and its Hydractive 2 suspension set up. I know the.

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Is there really much difference between a VSX Hydractive 2 setup and a normal set up in the SX in the driving department? Last edited by Mandrake; 26th December at The result is that the spring rate is kept constant, regardless of the load of the car.

Hydractive 2

The two modes are practically the same as on the previous Hydractive system: It was designed to overcome the biggest problem of the previous system, the very uncomfortable hard mode. Starting with Xantia model year and XM model yearall models featured an additional sphere that functioned as a pressure reservoir for rear brakes because of new hydraulic locks, letting the car retain normal ride height for several weeks without running hydractkve engine.

Above – the Xantia Activa undertaking the same slalom test at the same speed – note the total absence of body roll.

Above a schematic of the DS showing the suspension system. Im probably gonna get flamed for saying this but I just like the whole idea of my car sinking to the ground once I have parked it – I am more than willing to trade this off if there is a somewhat increased amount of driving pleasure in the handling and ride department?

Many manufacturers supply composite steel springs with a soft course and a stiff course – two different, discrete spring rates, whereas hydropneumatics offer an infinite number of rates. This page was last edited on 9 Septemberat At the heart of the system, acting as pressure sink as well as suspension elements, are the so-called spheres, five or six in all; one per wheel and one main accumulator as well as a dedicated brake accumulator on hyydractive models.


Hydropneumatic suspension

Its resolution have been doubled to 8 pulses generated per rotation, that is approximately 5 pulses per meter traveled although this depends somewhat on tire size. Hydropneumatic suspension has hhydractive number of natural advantages over steel springs, generally recognized in the auto industry.

Hydractive 2 is also fitted to most XM models. Height correctors act with some delay in order not to correct regular suspension movements.

This simplifies the ball valve arrangement with respect to Hydractive I. The system switches from “soft” to “firm” modes according to a number of parameters programmed into the on board computer.

The reason for this is to equalize the pressure between all three spheres of an axle. Spheres At the heart of the system are the so-called ‘spheres’ one per wheel and one main accumulator as well as a dedicated brake accumulator on some models.

Because the pressure there is proportional to the load, so is the braking power. Is this a Hydractive trait or do all Xantias do this?

When the suspension operates, the ram pushes oil into the sphere, thereby altering the volume and therefore the pressure of the gas. Yeah, to be honest, I just want to get the best possible car which I can afford at this stage. Spheres once had a threaded plug on top for recharging. This part of the circuit is at between and bars. Auto manufacturers try to balance these aims and locate new technologies that offer more of both.

In this new version the Sport setting would no longer keep the suspension system in firm mode, but instead lowered the thresholds significantly for any of the sensor readings also used in Comfort mode, allowing for a similar level of body firmness during cornering and acceleration, without the sacrifice in ride quality the Sport mode in Hydractive 1 systems had caused. Front suspension sphere Failure to keep the oil clean is the main cause of problems.


The hydraulic system acquired a reputation for unreliability when it was prematurely released on the DS.

Usually steel-sprung cars are either too soft “comfortable”or too stiff “sporty”or some intermediate compromise, while hydropneumatics offer “two cars in one”.

Citroën hydropneumatic suspension – overview

Each sphere consists of a hollow metal ball, open to the bottom, with the top and bottom of the sphere being separated by a flexible desmopan rubber membrane. The driver can make the suspension stiffen sport mode or ride in outstanding comfort soft mode. This is because of the inherent properties of a gas: Mineral oil is hydrophobic, unlike standard brake fluid; therefore, gas bubbles do not form in the system, as would be the case with standard brake fluid, creating a ‘spongy’ brake feel.

When the car is too low, the height corrector valve opens to allow more fluid into the suspension cylinder e. More prosaic but nevertheless useful benefits include the ability to drive on terrain that is normally restricted to off-road vehicles, the ability to raise or lower the suspension to assist in loading or unloading the vehicle, to assist in changing a wheel, to facilitate towing and to make washing of the car easier.

This section needs additional citations for verification. Brake servo with front to rear compensator 4. Daring to be different p.

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