At the risk of sounding obvious, don't bog it down off the line. Avoiding wheelspin in first is impossible if you want to run a quick time; that said, don't spin the wheels too much. If you change into second at the right time, it should just hook up in second. Then just leave it floored in second 'till you cross the finish line.
I've got a replay here for a 7.07 I just did. Good luck getting it to work because I've found it tricky watching replays of tweaked cars.