C5 Suspension Retro-fit

rossnunn · Post by **rossnunn** » 08 Dec 2010, 21:39

Hi guys,

Just signed up as I've a idea rattling around that I need to be put to bed or let grow.

Put very basically I'm thinking of retro-fitting the Hydractive system from either the Xantia or C5 onto a 106.

OK, OK stop laughing now!

I've taken a look at the exploded diagrams & the system does not seem that complex - just a lot of plumbing. I think could well be possible as the front struts look to be standard McPherson-fit into the hubs & the rear's maybe able to replace the 106's rear shockers. (I'm planning to keep the torsion bars athough I could replace these with pain steel rods)
I must stress at this point that I've done nothing more than looking at exploded diagrams & read various pages on the Hydractive suspension setup. I've not done any measuring & I am only looking at controlling the suspension & not the brakes or steering (as per the Xant)

I'm thinking, the c5 may be the better option (all be it abit more expensive as we have a old xantia thats due to go to the scrappers shortly), for starters, it uses a electric pump, as apposed to the mechanical one on the Xantia. Various (most)levers & bars used on the Xant are electronics on the C5, thus giving over to easier retro-fitting.
I did have concerns that the ride height would be waaaay to high but if the c5 knows which height it should be at it may well compensate for the lighter shell & bring it down to the right levels & if it doesn't, could the correct height be programmed? & how would the suspension handle the lighter body weight, but if its computer controlled it should it not compensate for this?
Another, quite major, issue I could see would be the front legs, as I remember the Xant's (my only real point of referance) strut towers are much lower than that on the 106 - to make room for the spheres, however could the top assembly be remote fitted using some custom pipework? (new strut-top mounts may need to be made) & would this have any adverse effects on the suspension's working - or again would the system just compensate?
& I've not even looked into if the mk1 C5 uses a canbus system? because that could be a proper ball ache.
Do the various conponents (like the Rigidity Regulator Sphere, Height Correctors etc) need to be mounted at specific points on the chassis or would anywhere be fine, bearing in mind it'll all be running on custom made pipework.
Does the C5 have a evolution of the Xants Activa anti-roll system? as it uses jacks on the end of the ARB's but can't see them on the C5's diagrams?

The reason for all this is my 106 is abit of a show thing & a track wanabe, so its lowered & while it looks great, the ride is rough as so this should give me the best of both worlds - in the real world it would ride like a carpet but at a show I can drop it on its bum & regain the 'looks', while out on track it should handle like a go-cart.
I've looked into custom air suspension but thats rolling in at funny money, where as I'm more than capible of carring out this modification if it does look to be doable.

Cheers

Ross

Toby_HDi · Post by **Toby_HDi** » 08 Dec 2010, 21:41

This sounds very similar to my idea to fit the Activa system to my 406 Coupé. I shall be watching this thread with great interest.

The C5 was never offered with Activa suspension.

See my original thread here for some thoughts

Post by **CitroJim** » 08 Dec 2010, 21:47

Hi Ross,

Good to see you back again. Welcome again

That's one very interesting project! I'm sure it is very doable with time and patience and it'll certainly make the 106 a bit more comfy...

I see no great problem in remote mounting spheres and sphere blocks. I believe this was done on a rally car once.

Have a natter with Chris570 as he is looking into something similar and has carried out a lot of research already. A PM to him may be a good idea.

Post by **xantia_v6** » 08 Dec 2010, 21:49

I think it is a nice concept, but one difficulty is that the Citroen front strut needs space above the mounting plane for the strut top and sphere, whereas a steel sprung car has the space below the strut mount for the spring. This implies a degree of butchery required to make it fit. Maybe easier(??) to adapt a double wishbone design from an earlier Citroen.

Xaccers · Post by **Xaccers** » 08 Dec 2010, 22:05

I do recall hearing about an AX that was fitted with hydraulic suspension, I believe the LHM resevoir was in the passenger foot well.

rossnunn · Post by **rossnunn** » 08 Dec 2010, 22:07

wow thats for the prompt replys guys! lol

Toby - I'll have a read.
CitroJim, yeah I suddenly had oh I bet its... moments when loging in! lol. I shall PM Chris570
Xant v6 - I've looked at a exploded diagram of the front legs & the strut itself looks very similar to a standard unit & as I mentioned, I'll be relocating the spheres/blocks off the top of the strut units.
xac - mmmm unfortunatly not a option for me, but the glovebox.......

rossnunn · Post by **rossnunn** » 08 Dec 2010, 23:10

out of interest, is there any interaction between the sphere system & the top of the strut, or does the strut just bolt through the housing (using it like any regular top mount) & a pipe runs from the lower part of the strut bolting into the sphere block?

Chris570 · Post by **Chris570** » 09 Dec 2010, 06:55

rossnunn wrote:out of interest, is there any interaction between the sphere system & the top of the strut, or does the strut just bolt through the housing (using it like any regular top mount) & a pipe runs from the lower part of the strut bolting into the sphere block?

yes, the system is fed from the top.

it is possible to relocate spheres and technically not that hard. certainly one of the easiest of the things you'd need to do.

i'm pretty sure you'll have clearence issues with the strut tops on the 106/ax area and of course you'll have to remake the holes as the ax has 2 106/saxo has 3 but the xantia has 4 holes for the strut top.

The balljoints are different as the ax series has the pin going up into the strut and of course xantias/c5 have them going down. so you'd have to fabricate your own wishbones.....

the steering arms are up high on the 106 and are down low on the xant. you can't just put the steering arms at that high on the xantia as you're then not acting on the hub you're acting on the ram, now in theory that *could* work, i wouldnt like to do it, too risky for me.

then you have the driveshaft issue, there are ways of mating xantia gear to the TU system....

Brakes, well you couldnt use the xantia system as its LHM powered and Dot 4 won't agree with it for very long, i'm pretty sure though that the 106 Gti and Berlingo calipers do fit the mounts although the offset will be wrong for the brake disc.

front ARB.. well this feeds the Height Corrector on the Xant so you'll have to modify that somehow, this bit has to be robust for obvious reasons.

The Rear, now in theory just removing the shocks could work but iirc the travel isnt sufficient. The rear rams on the xant has approx 14cm of movement and the AX rear beams don't have that on the shocks so you'd either have to move mounting points to get that or compromise on the ride quality (but then why go to all this trouble...)

One last thing, leaving the TB's in the beam will effectively mean you have 2 springs for each corner, i serioulsy wouldnt do that, unless you're planning on running heavy weights in the back the Hydraulics will only be doing the damping so you'll get no real benefit. Problem is though as i'm sure you know without the TB's in the trailing arm will most likely come off.

Rear Arb, a whole heap of fun.

in summary, it is do-able, anything is doable. It will be a LOT of work when tbh you can (dons fireproof suit) get a similar ride quality using spr!ngs as the car is so light.

Also make sure if you do it that the donor car has hydractive otherwise there is no point at all doing this as you'll lose all the good handling that these small cars have.

oh and the pump is the easy bit

if you would like more help and info i'd be glad to give it to you, just know the scale you'll be delving into

Here Endeth my longest post

Post by **RichardW** » 09 Dec 2010, 07:46

There's a bit more room around this chassis, but anything's possible!

Cit suspension transplant

HDI · Post by **HDI** » 09 Dec 2010, 09:54

Keyrist !!
Just begs the question, WHY ?

Post by **Paul-R** » 09 Dec 2010, 10:14

Now there's a man with just too much time on his hands.

Still, it must have kept him off the streets...

addo · Post by **addo** » 09 Dec 2010, 10:27

I've given lots of thought to fitting Citroën brakes to the 405 - once a doseur fan, you're forever stuck!

So, the OP's ponderings are not that weird to my way of looking at things. I've eyeballed 406 vs Xantia and the hub carriers/BJs are the same part number, it's just the strut/spring/sphere bits which vary. The 406 struts do come excessively close to the bonnet for clearance with a sphere bracket and it would be easier to retrofit springs to a Xantia front end than spheres to a 406 - suspect the same theory applies to the 106.

For the rear, what about examining the Mi16×4 as a cue for integrating hydraulics?

Alfa Selespeed pumps might be another good pressure source; they pump up to around 62 bar and are compact - you'd bodge up the valve block passages that weren't required.

Xaccers · Post by **Xaccers** » 09 Dec 2010, 10:38

There was a video posted on here of a badly modified 406 which had Xantia suspension fitted.
The general consensus was "So why not just buy a Xantia and have a better looking car for a hell of a lot less work?"

You could always buy a Xantia and build it up to look like an oversized Saxo

Citroenmad · Post by **Citroenmad** » 11 Dec 2010, 22:34

Handling, looks and ride quality all from one suspension set up? ou wont find that anywhere else other than on a Citroen!

Every C5 is multiplexed canbus, which operates the electronic suspension pump.

No, as said, the C5 didnt get the Activa anti roll control system, its a shame as im sure they could have made it a more viable feature on the C5, given its less pipework etc. Squeezing all of that into a 106 would be very tricky, where would you put the 10 spheres?!

Standard C5s have 4 spheres, while Hydractive3 + C5s have an extra two. This system works just like the normal hydractive 2 on Xantias and S2 Xms, cutting in and out of sports mode when needed, maintaining ride quality while offering slightly less roll and a better feel/stability.

I wouldnt like to think about swapping it from a Xantia or C5, as im not that mechanically minded, but im sure it can be done.

Had it of been a bigger car you were trying to swap it to, it would be easier.

Someone wanted to buy our old Activa to pinch its Activa-ness for a DS project. We wouldnt sell it to him, he did eventually buy an Activa but as far as I know the project never got any further.

So your not the only one with big ideas for Citroen suspension!

handyman · Post by **handyman** » 12 Dec 2010, 11:13

There has been a ZX converted to Hydractive suspension a few years back and it was quite successful. I'll try and look up the details and see if I can post a link.

Probably the easiest way to build a 106 with moded suspension would be in the same form as the Landrover. Make a chassis, with everything mechanical bolted to it, then add the bodywork, suitably modified to the chassis. It will save a lot of time and effort as you will know the chassis has integrity, whereas a monocoque body that has been hacked about will require additional strengthening and reinforcement which may not be physically possible if you are adapting a current bodyform.

When I used to build rally cars, we started using HC Viva & Chevette body shells, but found out very quickly how easy it was to rip off the front section, from the bulkhead forward.

I eventually started making strengthened subframes that were more like complete chassis. That worked really well until they changed the rules for production cars.

Your next problem, if you intend to use the car on the road, will be getting an Engineers Report and getting it past the SVA, as it will be classed as a modified car. Might also be worth running it past a specialist insurer. The quote might put you off!

Then again, you may live on a huge private estate with your own tarmac roads. No need for insurance then.

Handyman