Autometer 6871 tach
 

Who is running an Autometer "Ultimate Playback" tach?
I have a wiring question about the blue wire...

Re: Autometer 6871 tach
 

the Blue wire is for the trigger

have a look here this may help you

http://www.autometer.com/productPDF/0887F.pdf

regards
rod

Re: Autometer 6871 tach
 

Thanks Rod;
The instructions state....... NOTE: Playback tachs, and Playback boxes must have 12 volts applied to the blue wire. Recording will begin when 12 volts is removed......

So if I run the blue wire from, 12 v source through a n/o momentary switch, and then to tach.... I hit the momentary switch just before I leave, and the tach starts recording?
This tells me that the "blue" wire only has to see 12 v for an instant.... Is this true?
As you can tell, I'm not much for understanding auto wiring, and I need lots of help simplifying it... :-(
TIA

Re: Autometer 6871 tach
 

These tachs are really made to be wired into the transbrake solonoid so when its released and the 12 volts goes away the tach starts recording beyond the 10 seconds that is already being held in memory so you can get 10 seconds before the run and the auctual run. I tried to figure out a way to put a momentary switch on the throttle linkage of my footbrake car and never found a good way to do it. I ended up putting button on the steering wheel and as soon as the other guy prestages I hit it and stageto give the tach the momentary 12 volts it need to start recording. The bad part of doing it this way is, first its one more thing to do when staging the car and second if the track doesnt have autostart and the other guy takes forever to stage or tries to burn you down it wont record the whole run due to the limit on how long it will record the run. If anybody has a good way to put a monemtary switch on the throttle linkage I would hear about it. At first I tried a NOS microswitch on the throttle body thinking when I went wide open at launch it would trigger the tach but the tach needs to see 12 volts and then starts recording when the 12 volts goes away so that did not work. I tried a couple of other ways but never came up with something I felt was safe and consistant. Again if anybody has something that works and would be willing to share there idea I would like to hear about it.

Re: Autometer 6871 tach
 

I have an LTM and I have the blue wire triggered by the brake light switch. The blue wire picks up power from the brake light side of the brake light switch, then it goes through a toggle switch on the dash and then to the LTM. When I have stagged I flip the switch on (energizing the blue wire) and when I release the brake pedal it breaks the circuit to the LTM and it starts recording. Works good, but it dosen't record the burnout or staging rpm, but it does start recording before the converter flashes, so you can see the stall speed. Like the other guys stated, they are ment to work with a trans brake.

Re: Autometer 6871 tach
 

Dealt with this last weekend in Houston. Kevin Helms had me wire it straight to the line lock. Worked perfect after that. ED

Re: Autometer 6871 tach
 

ED;
Can you diagram your "blue wire" hook up for me?
Just to clarify....... I use my line lock for burn outs only. No trans brake. Foot brake only.

Re: Autometer 6871 tach
 

Line lock button for me. It does record end of burnout and staging car, but has had enough time left over for recording to get entire run. I think 90 seconds total.

Re: Autometer 6871 tach
 

Excellent timing, I was just about to post a similar thread.

Re: Autometer 6871 tach
 

Rallye Bob-

Another way, use a brake line pressure switch connected inline of your braking system with a TEE, they are two wire, begin with a 12 volt switch in the car to power wire once you prestage, arrow down /enter/enter on the tach, and leave. Removing your foot from the brake pedal will start the recording plus three seconds and you'll be set. If you decide to use a two step you can utilize the same circuit, however you would have to remember to shut the 12 volt switch off in the car to prevent the two step from energizing through the traps while braking, or install a long arm switch to interupt for hi gear.

Tim