Friday 4th September 2009

SOTW: Citroen Xantia Activa/MX-5 update

Shed falls head over heels for a hydraulic hero

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Dull looks, fascinating suspension

To commence today's SOTW, a caveat: before you start thinking that Shed has taken leave of its senses, we know that an old Citroen Xantia isn't exactly classic SOTW material. Bear with us, though, because this one's more interesting than most.

This Citroen Xantia is so fascinating because it's an £800 slice of automotive history; the Xantia Activa has the honour of being the world's first production car to be fitted with active suspension, where body roll is actively countered by electronics and, in the Xantia's case, hydraulics.

Taking a logical step on from Citroen's trademark hydraulic suspension, the Xantia Activa has two additional hydraulic rams and gas-filled spheres that, in conjunction with some sophisticated (in mid-1990s terms) computer technology, minimises the Activa's body roll through corners.

In basic terms the Activa system is a two-part process. In the first part the suspension's anti-sway bars run soft in a straight line, but the gas spheres are isolated on turn-in, doubling the stiffness of the suspension.

The next bit is even more ingenious. During long cornering, the two extra hydraulic rams (one at the front and one at the rear, set on opposing corners) firm-up the anti-roll bars, countering body lean. A roll corrector that works in a similar way to Citroen's self-levelling system regulates the pressure of the rams, and allows no more than half a degree of lean.

The result was eerily flat and surprisingly grippy cornering. As the seller points out in the advert, French car mag l'Automobile measured a maximum cornering force of 0.94g, which compares very favourably with the 0.93g managed by a Honda NSX or the 0.92g recorded by the Ferrari 512TR. Not bad for a family saloon wearing 205/55 R15 tyres.

There were downsides to the Xantia Activa, however, not least of which is the thoroughly humdrum appearance. There was also the pretty ordinary 150bhp 8-valve turbocharged engine, which was originally developed for the Citroen XM.

The Activa was also criticised for a lack of feel - because of the roll-free cornering, it was hard to tell where the limit of adhesion was. Even so, take a look at the comparative cornering pics of an Activa and an Audi A4; it's hard not to be impressed.

This particular Activa looks to be in fairly fine fettle. The seller says that it's had new discs and pads, handbrake cables, exhaust, and front brake hoses in the past 1000 miles, and that all 10 gas spheres are still under warranty.

There's evidence of the car's 103k miles in the form of some minor paintwork chips, a relatively tatty interior and worn alloys, but it's nothing out of the ordinary for a 13-year-old car. although the Rover radio is a bit peculiar. So is £800 good value for such a fascinating automotive curiosity? We reckon so, but it depends on how much you like hydraulics...

You can follow the link to the advert here

 

 

SOTW Special: UPDATE

One Shed Special. Never raced or rallied...

Just a few hours after we published Friday's SOTW Special, we were contacted by a chap named Mike Breslin, who told us of his surprise to see we had bought his old car; one that he thought no longer existed!

Mike told us that he had sold the Eunos with a few faults to a trader who had planned to scrap or break it, but evidently there was a change of heart, and the car was tidied up and sold on.

A longer chat with former owner Mike revealed that he is a motoring hack himself, and used to use our humble shed for reviewing track events all over the country for various magazines. Mike also wrote the Haynes Track Day Manual, in which our car is pictured several times (a copy will be included in the sale of the car).

Perhaps the best news of all was that Mike still had the service history, which he has kindly sent to us, along with a spare key. We've also sourced a badge thanks to helpful PHer Risotto. Just a few more bits to do and our little Mazda will be back on the market.

Track day at Lydden

Haynes Track Day Manual

 

 

[joe_90]

I almost died in one of these.
I was being shown its 'handling' but we had not gone in a straight enough line for the car to calibrate before tooling into a corner at mach 5....

[muckyman]

didn't the Toyota Soarer (UZZ32 model) have fully active suspension before the Xantia Activa?

[G0ldfysh]

top shed, this is something i have always been interested in would be ideal smoker for the winter hmm tempting.

[EDLT]

Less body roll than an MX-5! Its weird that they haven't used that suspension set up on any Citroen since the Activa (as far as I know), although I've read somewhere that a development of the active anti-roll bars are used in Range Rovers.

[adam85]

Nice! That's a bargain especially with said new items. Suss out a cheap headunit and you are laughing!

[Tracked_Out]

That interior is minging! Look at the steering wheel and driver's seat.

And would you buy a car from a guy whose eBay name is "Sweaty fox"...?

[_Nathan_]

Can Pistonheads employ people who actually know about cars?
"hydraulic" please...

Hydropneumatic

[Ricky944s2]

Does it contain Bifidius ActiRegularis like the yoghurt???

[adam85]

Tracked_Out said:

That interior is minging! Look at the steering wheel and driver's seat.

And would you buy a car from a guy whose eBay name is "Sweaty fox"...?

Donald Cox?

[Lord Pikey]

I miss my Xantia

[daimo_45]

Hydraulics use oil/liquid and you mentioned gas spheres? Don't you mean pneumatic or something?

[Garlick]

Now we'll never sell that MX-5 as last owner OAP, previously owned by a vicar who used it as a shopping car.

[B Oeuf]

EDLT said:

Less body roll than an MX-5! Its weird that they haven't used that suspension set up on any Citroen since the Activa (as far as I know), although I've read somewhere that a development of the active anti-roll bars are used in Range Rovers.

Probably because you need to replace the spheres on a regular basis. Mind you if your arms and legs resemble that of an Orung Utang and you find simple faults that require the combined skills of NASA and an Exorcist amusing then you're a match made in heaven.
At least this one has a turbo bolted to its feeble excuse for an engine, ours was a simple 8 valve unit and I can still recall the asthmatic mmmmmwwwaaaaaaaw as it rocketed forward with all the pace of the local vicar on his pushbike with great fondness and the look of astonishment on that truck drivers face when he nearly rammed us on a roundabout was a picture. I also found the complete disregard for supplying the warning lamps with bulbs very amusing and the subsequent bollicking from a cop for driving around with fogs on in the middle of summer something to be remembered. A great car that my nervous tic never lets me forget.

[adycav]

article said:

fascinating automotive curiosity

I reckon that's exactly what it is, and a good find to boot.

Strong shed.

[Strawman]

Garlick said:

Now we'll never sell that MX-5 as last owner OAP, previously owned by a vicar who used it as a shopping car.

Never tracked or rallied

[Riggers]

_Nathan_ said:

Can Pistonheads employ people who actually know about cars?
"hydraulic" please...

Hydropneumatic

Goodness. Hydropneumatics is a type of hydraulics. But whereas traditional hydraulics is concerned purely with liquids, hydropneumatic suspension, as i understand it, is hydraulic suspension that uses liquid and air.

Clue's in the name. Hydro - water; pneumatic - air.

[G0ldfysh]

Didn't it get called something like oleopnuematic? [sp]

[briancorish]

muckyman said:

didn't the Toyota Soarer (UZZ32 model) have fully active suspension before the Xantia Activa?

Yep, you're right. Way back in 1991 and it was a far more advanced system too. I had one. With the 4ws the handling was like playing a computer game!

[Swervin_Mervin]

B Oeuf said:

EDLT said:

Less body roll than an MX-5! Its weird that they haven't used that suspension set up on any Citroen since the Activa (as far as I know), although I've read somewhere that a development of the active anti-roll bars are used in Range Rovers.

Probably because you need to replace the spheres on a regular basis.

Or you could just get them re-gassed, which isn't costly at all. And as far as I'm aware, although could be wrong, subsequent iterations have been used by Citroen on the C6 and the C5 in Hydractive form.

[gareth_r]

briancorish said:

muckyman said:

Didn't the Toyota Soarer (UZZ32 model) have fully active suspension before the Xantia Activa?

Yep, you're right. Way back in 1991 and it was a far more advanced system too. I had one. With the 4ws the handling was like playing a computer game!

Although there were only 873 "Active" Soarers, so it was a pretty low production model.

Some technical stuff on the Soarer http://planetsoarer.com/UZZ32/uzz32.html

Edited by gareth_r on Monday 18th April 09:34