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308 Track Ride Height

Discussion in 'Technical Q&A' started by pma1010, Aug 29, 2004.

  1. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
    Full Name:
    Philip
    Having just put adjustable collars on the shocks, I am trying to set the ride height. Here are the specs today:
    - F: 3.5 deg neg camber; stock caster (4); no toe
    - R: 2.5 deg neg camber; stock toe
    - Rake: 1 1/4 inches measured from chassis rails, center of each axle
    - Rear lower control arms parallel to ground @ 34 psi; (front a dihedral, set by rake)
    - Ride height: F, 2 5/8 inches (chassis to ground, middle of control arm); R: 3 7/8

    Precise setting will change after corner weighting, but in general, anyone have experience with running different ride heights? This is where we need Mitch and Rob!
     
  2. carl888

    carl888 F1 Rookie
    Silver Subscribed Owner

    Oct 31, 2003
    4,161
    Melbourne, Australia
    Full Name:
    Carl Jones
    Hi Phil,

    Yes, two years of palying with the ride height on a 308 GTB. The ride height issue is meaningless without knowing the tyre size if you are quoting chassis height.

    Seocndly, you are not running any where near enough toe for a track setting. You need at least 5mm total on the back of a 308. Finally, what caster are you running?

    Regards,

    Carl.
     
  3. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
    Full Name:
    Philip
    Here's more data:
    Front: 205/55 x16; have run 225/50x16; Rear: 245/45 x16. All at 34 psi.
    Ride height = chassis measurements.
    Castor 4 degrees (F)
    Rear toe (stock) so 3 to 4 mm (I don't have the alignment sheet to hand).
    ARB (adj) setting: (F) 18/[22] mm; (R) [16]/18mm

    Rear of car has been well planted before changing to adjustable collars on the shocks but ride height was an inch or so higher (F) with little/no rake.

    Turn in has been fine (to my relatively untrained hands).

    Issue has been mid-corner understeer reflecting weight shift F->R under acceleration when using only mildly uprated springs (~+30%). Have since put on 350lb F, 275lb R springs.

    All ride height settings will change (slightly?) from corner weighting (to come - I am trying to see if I am in the ballpark with others' experiences).

    Hope to try it all at Grattan & Road America next month.
     

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