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It’s been around in the US for some time and is starting to appear on more mainstream models, but in Europe Delphi’s Magneride magnetic suspension system remains confined to the premium (and expensive) Ferrari 599 GTB and Audi’s new TT and even newer R8 – the last only just revealed at the Paris Motor Show.

Continuously adjustable electric suspension systems require electro-mechanical valves, motors, springs and shims to provide differing levels of damping force. Delphi’s system replaces this with four monotube dampers filled with magneto-rheological fluid and connected to a sensor set which is in turn linked up to an electronic control unit (ECU).

The fluid is a suspension of magnetic particles in a hydrocarbon base fluid, through which an electric current can be applied via a coil in the damper piston. When the current is off, the fluid behaves like any other damper fluid, allowing the piston to move freely.

When current is switched on, the resulting magnetic field causes the particles in the fluid to align into fibrous structures in the direction of the magnetic flux, providing resistance to fluid flow through the damper piston.

The current, which requires a maximum of 20W per damper, can be adjusted to allow the generation of a wide range of damping force, allowing ride quality to be changed from soft to hard – and the effect takes place almost instantaneously.

Dave Hoptree, marketing manager for Delphi chassis systems, explains that although the technology has been around since 2002 on Cadillacs in the US, Europe has been a little more cautious on the uptake: “It’s a new technology and OEMs in Europe are very careful and want to make sure it is reliable and that they understand it.

“It’s in the field now as well, so they can stand back and see the actual performance – we’ve bought back parts that have been in use now and re-examined them to make sure the testing we’re doing in the lab corresponds to the actual performance, ensuring the durability. We’ve been able to use this as evidence for our new customers.”

Delphi markets other adjustable suspension systems, but these have gone out of production in the last model year, with everything now being transitioned over to the controllable fluid technology.

Hoptree says: “We see how much better it works for us; it responds much faster, has a much greater range of damping authority and simply performs much better in the car than the old valve based designs that we produced in the past. We exceed the performance capabilities in every single category that we measure, from handling to ride comfort and small-impact feel.”

Comparing cost is more difficult. The technology can be adjusted for different levels of sophistication, ranging from a switch in the dashboard as in the TT which according to Delphi is “fairly economical”, up to more expensive systems with controllable dampers, ECU and sensors.

Delphi will only be drawn to say it believes the system to be “competitive” with the other systems. Audi has said that while the magnetic suspension system it uses on the new TT is more expensive, it’s hoping that over time costs will start to come down and it will be possible to offer it on more mainstream models.

The application of the magnetic suspension can vary depending on the philosophy of the manufacturer. While for cars like the TT it is desirable to allow the driver control over whether the ride is firm and sporty for hard driving, or softer and more comfortable for cruising, many luxury cars will use the ECU “simply” to provide a constant, smooth ride that adjusts automatically to take into account road conditions.

The system can also be used to hold individual preferences for multiple drivers, in the same way as you might adjust an electric seat.

Hoptree says “This is going to be a real growth area as more of the OEMs become convinced by the technology.”