I have a 2001 Z28 with lid/cat back, CAI. Now, I am figuring this....I have to shift to go through the traps in the quarter almost at the end. If my trap speed is an average of lets say 107-109 MPH, that means that since this is a moving average, I'm actually doing about 110-112 at the end point. Would the car be faster through the traps if I were to go from 3.42 to 3.23 or 3.15? It seems that if I were to go DOWN to a taller ratio or two, I could stay in the power band longer and NOT HAVE TO SHIFT into 4th at the end. I'm not going to do this, but I think it's an intellectuallu cute question. Any thoughts? Thanks.

 

You would be able to keep your car in its power band at the top end of the track longer... this is true... however

It takes longer for your car to initially get into the power band from a stop with a taller rear gear... Once you are at the top of first you are essentially in the powerband of the motor (therefore putting out max hp) for the rest of the track. Delaying your engine gettting to that rpm is not good. If you are delaying this "max power" you are not going to accelerate as quickly, and therefore have a lower overall velocity.
I may not be right about this but I would imagine there is more "load" on the engine... ie more resistance to turn at the desired rpm which cannot be good either.
Basically if your theory worked my 72 442 with ~350 hp and 3.08 gears should trap higher than my camaro with ~340 hp and 3:42 gears. (OK the 442 is an auto with a "built" tranny, the gear ratios are similar to 1, 2 and 4 in my M6 car)
The cutlass' race weight is ~3700lbs, the camaro ~3650. The camaro traps at 106+/- the Cutlass traps at 99-101 mph. Their Et's werent much more comparable, with the cutlass running very high 13's at best. I have yet to get a "best time" that I think reflects the Camaro's potential.