Brake pressure switch

[bmedeirs]

I use a switch from PDI PDAH-4-4M-C-FL-9. There are older versions of this switch that have a similar part number. There are a couple of these currently on ebay.

http://www.ebay.com/itm/PDI-PPDI-PDA...item35ac4b4a0d

http://www.ebay.com/itm/DYNAMIC-AIR-...item1c25be9020

You need a second switch in series on the shifter in first gear position so that the brake pressure will closed the micro switch when you step on the brake at the starting line and the switch on the shifter most be in first gear and closed also for the two step to be activated. This prevents the two step from activating at the finish line if you foot brake at the stripe. I use a common bump switch for the shifter mounted on a small bracket. I brake pressure gauge with a small light built into it is also a good option also. The pressure switch must be installed with the red wire (Normally open) and also the black wire = common. The pressure switch is adjustable, remove the screw from the top of the switch, using an 1/8 allen wrench to adjust clockwise to increase set point and counter-clockwise to decrease set point. Then replace the screw. Works by staging, stepping on the brake hard, stepping on the gas, releasing the brake to launch.