i dont understand this. the instructions say to get the 12V for the blue wire from the downstream side of the break switch. now i understand this getting power with the breaks applied but when you release the breaks the 12V is dropped (aint it). am i miss understanding this? is there a better way to hook the blue wire up? thanks Dave

Dave,

I wired mine as follows:

I spliced into the brake switch on my brake pedal. This is a normally closed switch, which means that power is applied when it is open. Take a voltmeter and look for the side of the switch that has power when the brake pedal is depressed. I then wired a toggle switch into this lead and mounted it under my dash. This way I can control when 12 volts is applied to the tach rather than having it applied each time I depress the brakes. Tie the blue tach lead into the other side of the toggle switch. When using the tach I set it to record. You will go through the pre and burnout stages without engaging the toggle switch. Once you have the car staged and the brakes applied throw your toggle switch. This will send 12v to the tach. When you release the brake at launch the 12v will be removed and the run recording will begin. Make sure that when you get done with the run that you turn the toggle switch to the tach off. I've forgotten to do this on a few occassions. It seems that sending 12v to the tach when it's not recording can corrupt the stored data. I found this method works pretty well. However messing with the toggle switch during eliminations in a bracket race can throw you off your game. I normally only use the playback tach during time runs or testing. Once you've figured out your shiftpoints, how well you hit the shift points, calculate the converter slipage, etc..., you find that you don't use the record function much anymore unless you're making changes to the car and trying different shift points. The TachFacts software that you can download to a laptop/PC works pretty well. My biggest complaint is that the times lines on the graphs could be a little more granular.

HTH.

ok Ken, ill give it a try. it looks like the way you described it if i read it right, the tack is internaly switched. needing the 12v only to start the recordng. thanks Dave