Page 2 of 2 FirstFirst 12
Results 11 to 15 of 15

Thread: Self-levelling Air Suspension System

  1. #11
    Senior Member Ice Cube's Avatar
    Join Date
    Nov 2013
    Location
    West Midlands
    Posts
    1,611
    Post Thanks / Like
    I understood that it takes readings from the 4 level sensors and makes height corrections many times a second.

    The car lowers itself by 15mm at 100 mph.
    2008 XJR + sun roof + soft leather + ACC + retrofit: burr walnut interior trim
    ++++++++++++++++++++++++++++++++++++++++++++++++++
    2007 X-Type 3.0 SP Auto + retrofit: walnut dash & gear knob + rear sill protectors + mudflaps + Al powerwash crucifers + memory powerfolds

    "Life's too short for touchscreens - give me lots of nice buttons to press"

  2. #12
    Senior Member Glenn65's Avatar
    Join Date
    Jun 2017
    Location
    Larkhall
    Posts
    390
    Post Thanks / Like
    I’ve seen mine do a sort of dip and rise if stopped at lights and I put the handbrake on.
    Crapped myself when it happened the first time it happened.

  3. Likes Nimiq1 liked this post
  4. #13
    Senior Member FastEddie's Avatar
    Join Date
    Apr 2017
    Location
    Milton Keynes
    Posts
    1,428
    Post Thanks / Like
    If you sit in the car and fixate on something in the rear view mirror before you start up,

    You will see the back end rise up first , then the front lifts up to the level position so the lights are never too high.

    When you put it in park / neutral and apply the park brake , it does the reverse of the above.

    By putting a block of wood under / one rear wheel up a kerb , the level 100% articulates to suit every time on mine.

    There is also a sensor of some description mounted in the boot on the back panel near the fuse box,

    Is this an accelerometer that adjusts the damping rate ? Or is it a sensor for something different altogether ?
    2009 X358 XJ LWB 2.7 Tdvi , Liquid Silver , 100k+ and going strong.
    Bumper reflectors drilled and fitted with 3W side marker lights.
    Fog lamps / DRL running with HID colour match of dipped beam.



  5. #14
    Senior Member Partick the Cat's Avatar
    Join Date
    Apr 2013
    Location
    Thornbury, Gloucestershire
    Posts
    1,051
    Post Thanks / Like
    Quote Originally Posted by Ice Cube View Post
    I understood that it takes readings from the 4 level sensors and makes height corrections many times a second.
    Yes the suspension heights are measured many times a second but the values are smoothed (averaged): through a fast filter when the car is stationary so it can compensate for luggage and passenger changes orthe fuel tank being filled; and through a slow (long time constant) filter when the car is moving so that it only reacts to long term changes - fuel usage.

    As to making many corrections a second, no. That would wear out the air valves and the compressor in a week. All auto control systems (well, all digital ones and many analogue ones) have a 'dead band', a small band within which they don't try to alter things. Off hand I think it's 5mm when the car's moving.
    Last edited by Partick the Cat; 11-08-18 at 08:57.
    "The jaguar is a compact and well-muscled animal." (Wikipedia on Panthera Onca)
    2008 XJ Sovereign 2.7 Tdvi,
    LWB, Sunroof, 19" Polaris, Botanical Green
    2008 Hyundai Getz 1.4
    Previous: 2004 Hyundai Getz; 1990 Merc 190E 2.6; 1987 Nissan Prairie ... 1954 Mk-C 197cc Bond Minicar

  6. #15
    Senior Member Ice Cube's Avatar
    Join Date
    Nov 2013
    Location
    West Midlands
    Posts
    1,611
    Post Thanks / Like
    Took it for a run yesterday, and it's now sitting all square, so everything checks out OK. Relief!
    2008 XJR + sun roof + soft leather + ACC + retrofit: burr walnut interior trim
    ++++++++++++++++++++++++++++++++++++++++++++++++++
    2007 X-Type 3.0 SP Auto + retrofit: walnut dash & gear knob + rear sill protectors + mudflaps + Al powerwash crucifers + memory powerfolds

    "Life's too short for touchscreens - give me lots of nice buttons to press"

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •