Shift points are crucial to maximum acceleration. The ideal shift point in stock Corvettes is just before invocation of the rev-limiter or fuel cut-off. This conclusion comes from my calculations, verified by personal experiments at the dragstrip. Shifting before the ideal rpm-termed short shifting-produces slower acceleration adversely affecting both e.t. and trap speed. Conversely, perfect shift points can shed two- to three-tenths of a second in e.t. compared to very good ones.
If 6500 is the target shift point (for a Corvette with the LS2 or LS6 engine), the driver must get the clutch in at an actual 6500, ease the throttle, complete the shift, release the clutch, and reapply the throttle. Because engine rpm at wide-open throttle climbs at a different rate in each gear, the driver must calibrate clutch-in and associated movements to hit each shift point correctly. Special attention must be paid to the 1st-to-2nd and 2nd-to-3rd shift points in C5s because the tachometer needle lags behind the actual engine rpm at wide-open throttle. There is very little tach-lag in C6s.
If you overrun the target shift point, the penalty for barely kissing the rev-limiter is usually around five-hundredths of a second. But hitting the limiter squarely under wide-open throttle will cost at least a tenth, and even more if driver recovery actions are not extremely quick.
Finally, after the shift to Fourth gear, be sure to remain at wide-open throttle until beyond the final timing beam that marks the end of the quarter-mile.
The foregoing discussion provides proven recipes for good launch, strong shifts, and correct shift-points-the crucial ingredients of max acceleration. Knowing what to do is certainly a prerequisite, but actually performing all steps correctly and smoothly integrating them for a successful pass takes seat time and practice . . . a lot of practice.
A reasonable expectation is you will need 30-50 passes to find your personal lower limit for e.t. in a particular Corvette platform. You will need fewer passes if you are a gifted athlete, fast learner, or have previous race experience in a traction-limited, manual-transmission car. some drivers deeply committed to beating the Chevy spec for their cars manage to accomplish that goal in 20 passes or less. keep your expectations realistic. CF
Editor's Note: John "Ranger" Armstrong is producing a DVD on the aforementioned techniques for maximum acceleration in Corvettes. Scheduled for release the fourth quarter of 2007 via his web site (www.rangeracceleration.com), the DVD is intended to help Corvette owners get the most from their cars in a straight line, on the street, and at the dragstrip.