Blue Hills Raceway

Compression Molded Polymer Modified Car Class Rules (CMPM)

Legal chassis are:
BSRT G3/G3R/G3RS/G3RSB, Mattel/Tyco 440×2, Slottech Panther/Panther 02, Thundercat T3, T1X, Tomy AFX Super G+, Wizzard Storm/Fusion, Viper V1/V3, RPMs Ghost Cat

  1. The chassis must be stock, readily available, “HOPRA Approved” and cannot be machined, sanded or cut except
    to provide for the following:
    a. Add, remove or re-add body mounts.
    b. Mount any guide pin holder – guide pin shall remain in any one of the stock positions.
    c. Add armature bushings or ball bearings.
    d. Drill or cut holes for adjustable brush tension.
    e. The bottom surface of the chassis and bulkheads may be sanded flat. However, the bottom
    bulkhead tabs shall remain naturally connected to the end bells.
    f. The pickup retaining tabs on the chassis may be reinforced and/or replaced in their stock position.
    g. Add rear axle retainer.
    h. Add bulkhead/magnet clip retaining screws.
  2. All magnets shall remain in their stock location.
    a. Only “HOPRA Approved” compression molded polymer magnets may be used, see below for specific manufacturer part numbers. Magnets may be sanded flat on the bottom surface only, so
    they are flush with the bottom surface of the chassis and bulkheads.
    b. The gauss reading of the traction or motor magnet shall not exceed the following criteria. This is taken after 5 min cool down period and at the lowest point on each magnet as it runs parallel to the rail. Any reading above these figures will be cause for disqualification or rejection at tech.
    TRACTION: 2300 gauss maximum MOTOR: 2000 gauss maximum

    Refer to the HOPRA Website for current “HOPRA Approved” Compression Molded Polymer Magnets for Polymer Modified Car
    Magnets are listed by magnet manufacturer and may be used in all chassis adhering to class rules.
  3. All magnets shall remain in their stock location.
  4. The use of glue shall not be allowed on the magnets or to retain the magnets to the chassis. Other nonmagnetic
    materials may be employed to restrict the movement of the magnets. Any chassis clip used to
    hold the car together must not touch the magnets or affect the magnetic field.
  5. Any type of armature shall be legal.
  6. Electrical systems shall be stock or stock replacement. Adjustable brush tension is allowed.
    Physically attaching brushes to springs (using glue or other substance) or spring arm is allowed.
    Plated parts are allowed. Shunts are allowed.
  7. There are no restrictions on the armature bushings/ball bearings (may be glued in), guide pin, wheels,
    tires, gears and axles.