low mph

[donZ]

why would my mph be down ?
last time at the track, i ran 12.4 @ 113mph
this time 12.2 @ 107 MPH
ANY THOUGHTS ?

 

[azgn]

if you did nothing to change the HP you were making, it is natural to drop off in speed if your et improves....but 6 mph seems a bit much...........what were the 60' times and 330' times in both runs?