new valve springs springs

  1. Established Member Joined: Apr 2006 torquay (England) Posts: 1993 supercharged vts. 1.1 saxo. accord type r
    #1
    going to be running jp4 head with catcam 708s,
    rather than swap to the j4 springs and retainers,
    what would be a decent upgrade to run, 780o.
    thanks
    adz
  2. Frequent Poster Joined: Oct 2005 Posts: 751
    #2
    none, the j4 springs and retainers are perfect.

    The higher the spring rate the hysterisis ususally increases, so you have an increased energy loss.

    Not to mention the increased spring rate will increase the contact loading on the cam lobe which would increase wear rate and cam bending.

    Ideally you would want to use the lighest spring possible for the valvetrain weight and speed you want to run, keeping in mind the natural frequency of the spring should be over 15 order higher than the frequency of the valvetrain motion at peak rpm