Torque Converter

At what speed does the stock converter lockup at? Since most limits in downtown are 35 (cops are everywhere) I was thinking of setting the lockup speed at 35 to be more efficient.

Would that cause problems or wear (like going in and out of lockup)? What about shifts points (does it occur between shifts?)

and why are most converters set around 40 mph?

Converter has nothing to do with lockup speed, it only follows orders sent by the pcm and the tranny routes fluid to aply the clutch.

I know the pcm controls the lockup speed. that however was not my question