RE: Franco Sprocket

[Ned Ritchie <NED@IntendedAcceleration.com>]

Several years ago I tested a Franco Sprocket in a 5000CS TQ with a stock cam.
The following is raw data with some calculations:

ACCELERATION TIMES
Testing Variable Cam Sprocket:
3rd Gear only climbing a constant grade
Start at 1000 RPM - Measure times from 1500 RPM to 4000 RPM and 5000 RPM
 -----------------------------------------------------------------------
RATIONAL: 
Climbing a grade in third gear gives the longest times in which to measure any effect the cam timing has at any RPM

 =======================================================================
    Seconds to    Seconds to
    4000 RPM     5000 RPM

First Day @ 74 Degrees F
STOCK SPROCKET  &  ELECTRONIC BOOST CONTROL

    ----------------------
        9.49        11.76 Average times Stock Sprocket

        9.17        11.12 Average times with boost turned up a little


Another day @ 45 Degrees F
8 DEGREE VARIABLE TIMING SPROCKET  WITH STIFF SPRINGS IN THE SPROCKET
ELECTRONIC BOOST CONTROL SET AT MINIMUM
        9.46        11.79
        9.32        11.70
        9.26        11.86
        9.93        12.49
        9.10        11.67
__________________
        9.41         11.90 Average times

Same day @ 58 Degrees F
8 DEGREE VARIABLE TIMING SPROCKET WITH WEAKER SPRINGS IN THE SPROCKET
ELECTRONIC BOOST CONTROL SET AT MINIMUM
        9.23        11.56
        9.22        11.51
        9.27        11.64
        9.26        11.71
        9.21        11.70
        9.34        11.81
__________________
        9.26         11.66  Average Times
CHANGE TO STIFFER WATEGATE SPRING 
ELECTRONIC BOOST CONTROL SET AT MINIMUM
        9.30        11.68
        9.30        11.71
        9.23        11.67
    ----------------------
9.28        11.69 Average times
THREE RUNS WITH ELECTRONIC BOOST CONTROL SET AT MID POINT
8.88        11.18  Average times
________________________________________________________________


COMPARISON OF TIMES OF CAM TIMING ON REDUCTION IN TIMES TO RPM
VARIABLE CAM SPROCKET
                          STOCK         STIFF     SOFT     SOFT       MAX  IMPROVEMENT
    4000 RPM           9.49           9.41        9.26     9.28                      0.235
    5000 RPM         11.76         11.90      11.66    11.69                     0.108

EFFECT OF INCREASE IN BOOST ONLY
    4000 RPM                                                                               0.320    0.534
    5000 RPM                                                                               0.643    0.722

CONCLUSIONS:
Franco sprocket with a stock 5000CS turbo quattro engine cam does increase performance but could not feel in seat of the pants.
More effective to increase boost .
RECOMMENDATION:
I feel that better results could be obtained using a radically ground cam for high RPM performance and change its timing for better idle.