Delay using 5Dmk3 to remotely fire 40d

I recently tried using my 5Dmk3 to remotely fire my 40D via PW Flex and TT5. There is a rather long delay ( approx 1 sec) before the 40D fires. Distance is less than 50 feet and I set the 40D to manual focus and TV to minimize the time it takes the camera to set the exposure. How can I get this delay to disappear or be alot less. I'm shooting drag racing and by the time the 40 fires, the car is out of the shot.