Yet another sphere thread, but different!
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  1. #1
    1000+ Posts pottsy's Avatar
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    Default Yet another sphere thread, but different!

    I'm doing some heavy thinking with Moby Dick. Having done some research and a bit of careful measuring on the spheres I have, I'm fascinated by the large difference to be had by trying small changes in the "free flow" hole diameter of the damper valve.

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    I've checked my spheres and found that the ones that I had in the back of Moby, which were REALLY floaty, have a hole of around 1.9 mm. The ones I've put in now, aside from being inflated to half the amount of the floaty ones, have a smaller orifice of about 1.6mm. These feel great so far.

    I'm informed that the spheres fitted to Injected DS's were slightly "firmer" in that they had a smaller orifice, but I can find no listing of this. The only list I've found simply lumps all DS & ID models together as having 700cc spheres with 1.65mm holes.

    My "floaty" ones are ex CX sealed types, inflated to 800 psi and with the abovementioned 1.9mm holes. I'm aware that these are wrong for the DS, were horrific in the front and hilarious in the back, but expedient at the time.

    What I want to throw out for input is the concept of drilling and tapping the centre holes on a set of spheres, and then making a few sets of replaceable screws each set with different sized holes in them. Changing the damping rate would then be a matter of removing the sphere, changing the "jet" and replacing. Simple enough and food for thought considering the variety of events I'll be competing in during the Ampol re-run next year.

    Since I plan to have the original set of DS spheres fitted with new diaphragms, it seems the ideal time, while they're apart, to make this modification. This would avoid the risk of getting metal filings in the system.

    So what do we reckon? Has anyone any knowledge of this or similar mods? Anyone see good reasons for or against? Anyone got a set of orginal type DS spheres with the removeable dampers they want to give me to avoid all this fiddling? Any better ideas?

    All input is welcome. Go to it Brains Trust!

    Pottsy
    Buvito Ergo Sum!

    The Fleet:

    2018 C3 Shine ("Oscar" Mrs P's)
    1974 D Special Manual Sedan ("Moby Dick")
    2006 C5 HDI Wagon Auto ("Mephistopheles")
    1982 2CV6 ("Gaston") Seasoned traveller
    1975 GS Pallas ("GiSelle") Next project
    And for Fun, 1968 Mini Deluxe ("The R & D'luxe" 1078cc, Grin Factor 100!)

  2. #2
    Real cars have hydraulics DoubleChevron's Avatar
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    Pottsy,

    your lucky your talking DS's. Find yourself a set of DS spheres with removable valves. They were sold with removable valves until the 70's (I think). The valves were more like a stack of 'plates' that restricted flow. The more of them installed, the harsher the ride. It's possible to get an early DS19 ride if like that

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/citro%EBn-forum/90325-best-project-car-you-have-ever-seen.html
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  3. #3
    Fellow Frogger! blomquvist's Avatar
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    Quote Originally Posted by pottsy
    I'm informed that the spheres fitted to Injected DS's were slightly "firmer" in that they had a smaller orifice, but I can find no listing of this. The only list I've found simply lumps all DS & ID models together as having 700cc spheres with 1.65mm holes.

    Hi Pottsy,

    As the newish owner of an oldish Citroen, I'm still an ingenue in the sphere of spheres (still haven't found three of the seven in my car), can confirm the larger hole = softer ride relationship. GFS in the UK are selling "comfort" spheres for the XM, which have larger holes. For some discussion and the (happy) experience of a UK user, see http://club-xm.com/forum2/index.php?showtopic=385

    Cheers,

    Greg
    1992 Citroen XM 2.0i Prestige 1989 Peugeot 205 GTI S2 (Little Red Car for sale) 1998 Volvo V70R AWD (Big Red Car)

  4. #4
    UFO
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    CitroŽn Tragic UFO's Avatar
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    My D has the type of spheres that Shane describes on the rear. Floaty dude

    Some say it is the softest D they have ridden in, yet it still handles well.
    Craig K
    2009 C5 HDi Exclusive

  5. #5
    UFO
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    Quote Originally Posted by blomquvist
    Hi Pottsy,

    As a new owner of an oldish Citroen, I'm still an ingenue in the sphere of spheres (still haven't found three of the seven in my car), can confirm the larger hole = softer ride relationship. GFS in the UK are selling "comfort" spheres for the XM, which have larger holes. For some discussion and the (happy) experience of a UK user, see http://club-xm.com/forum2/index.php?showtopic=385

    Cheers,

    Greg
    Greg

    Your seven spheres are:

    1 at each corner = 4
    one accumulator - should be easy to find with a 4cyl XM - in the front left of the engine bay probably
    one centre at each end - one just below the firewall on a horizontal mount
    one above the heat shield/spare tyre area (remove spare tyre, undo two 10mm bolts that hold heat shield and look up - use of Citroen fingers is handy). This is the worst sphere I have ever had to get off an XM.

    To depressurise an XM properly
    Have car on four ramps or four post host
    Open bonnet
    Engine running drivers window down and door closed - you are OUTSIDE the car.
    Reach in and put hieght lever to LOW
    Leave engine run for 1 minute or so
    Turn engine off
    Leave car till you hear the centre sphere solenoid switches have ceased activation
    DO NOT OPEN ANY DOOR other than bonnet as this may reactivate the solenoids and lock pressure into the spheres resulting in your later having a douche verte!
    Release pressure release valve till you get PPHHHHT noise - no more than 1 turn EVER

    Go inside have cool drink and allow car to cool for a while or you will burn yourself on exhaust.

    Reassembly is easy.
    Craig K
    2009 C5 HDi Exclusive

  6. #6
    Fellow Frogger! blomquvist's Avatar
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    Default Music of the spheres

    Thanks Craig,

    I will now go in search of the elusive three.

    Quote Originally Posted by UFO
    one accumulator - should be easy to find with a 4cyl XM ...
    Yep. There's room for at least two more engines, or my 205 GTI as a back up

    Thinking of replacing the lot, as they haven't been looked at in years. Ride is ok, anti-sink not really working (not that I mind, as the XM has a shark-like charm while resting on its bump stops).

    Now where's that pressure release valve?

    Cheers,

    Greg
    1992 Citroen XM 2.0i Prestige 1989 Peugeot 205 GTI S2 (Little Red Car for sale) 1998 Volvo V70R AWD (Big Red Car)

  7. #7
    Real cars have hydraulics DoubleChevron's Avatar
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    Hi Greg,

    do you ever get upto ballarat

    We could roll the XM up onto some ramps and point out some spheres ... Infact we could whip them off and pressure test them if you like (I can't regass them though, I don't have a regasser).

    Plus ... I'd get to have a ride in an XM turbo deisel (I'm sure my father would love to see your car too ... He actually bought one of them in the UK from memory ... But reneged on the deal as he checked up on the car and it was under a hire purchase agreement to the previous owner prior to the person selling it... and didn't want problems shipping it out of the country).

    edit: woops you have the 2litre petrol XM Not sure why I thought it was a deisel ... Offer still of course stands Rogers been saying he's bringing his XM down too, but I haven't sighted that either

    seeya,
    Shane L.
    Last edited by DoubleChevron; 4th November 2005 at 06:18 PM.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  8. #8
    Fellow Frogger! blomquvist's Avatar
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    Default

    Quote Originally Posted by DoubleChevron
    Hi Greg,

    do you ever get upto ballarat

    Plus ... I'd get to have a ride in an XM turbo deisel (I'm sure my father would love to see your car too ... seeya,
    Shane L.

    Shane - I woz in Ballarat two weeks ago, but in the wrong car! (the Volvo Flying Brick). Would be great to have your assitance, and see your collection of Cits. This beastie is actually the 2.0, non-turbo petrol injected 8-valve, rather than the desirable diesel. Despite the small engine, it has enough power (130 bhp) and torque to move well, and long distance fuel economy is great. Doesn't seem slug-like, even after the 205 GTI - just more relaxed.

    Cheers,

    Greg
    1992 Citroen XM 2.0i Prestige 1989 Peugeot 205 GTI S2 (Little Red Car for sale) 1998 Volvo V70R AWD (Big Red Car)

  9. #9
    Real cars have hydraulics DoubleChevron's Avatar
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    No worries,

    if your ever heading up this way just let me know and I'll make sure I'm home

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  10. #10
    1000+ Posts pottsy's Avatar
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    It's amazing how a simple thing like a forum can so closely resemble how our minds work. I will start doing something which reminds me of something else, so I start that and so on....... (Or is that just a behaviour trait of the over 50's?)

    Without being rude or precious, I appreciate that the XM is a wonderful thing, and I'd love to have one but it's got little to do with my questions.

    As I understand the mechanism, the size of the orifice affects the 'feel' of the suspension under low speed transitions, that is, small bumps. (Remember we're talking vertical movement of the wheel here.) The damper valve assembly takes over control for more violent transitions, such as hitting a speed hump etc.

    What I'm aiming for is to subtly "stiffen" the ride of the DS to make it a bit less floaty under competition conditions, but without losing the classic DS ride on the road. I sort of hope that this will reduce the roll a bit, but it may not.

    By acquiring and changing the plates in a set of replaceable spheres, I would be able to change the transition rate of large bumps, but not increase the ride control by any appreciable amount. I guess I'm also looking for an easily variable means of experimenting. (And a relatively cheap and robust method)

    I reckon that Mr Citroen had all the sums right originally, but I wouldn't be a petrol head if I was content with that!

    Cheers, Pottsy
    Buvito Ergo Sum!

    The Fleet:

    2018 C3 Shine ("Oscar" Mrs P's)
    1974 D Special Manual Sedan ("Moby Dick")
    2006 C5 HDI Wagon Auto ("Mephistopheles")
    1982 2CV6 ("Gaston") Seasoned traveller
    1975 GS Pallas ("GiSelle") Next project
    And for Fun, 1968 Mini Deluxe ("The R & D'luxe" 1078cc, Grin Factor 100!)

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