If you do a lap and come off the end of the bridge with a BR then hit a turbo quickly, press the select button again to give yourself another turbo Before the start line,then quickly use that one,you will be traveling at max speed at the start of a zico attempt lap .
You still get another turbo as you start a lap to use to do your multiple BR's down the straight.

It's a sort of "Boost BR Boost" trick for dummies without having to nose up at the start.