Connecting engine's RPM signal to LogWorks?
 

Am setting up a dual wideband using LC2s and will be datalogging using LogWorks. To better interpret Lambda data I'd like to trace RPM alongside the Lambda. But, I have no idea how to tap into the car's RPM signal. Have an '85 3.2 in an '80 911. Any help with this would be appreciated.
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I think you should be able to tap into the tack signal wire on the back of the Tach Black/Violet wire located at terminal #2 on the tach. it originates from the DME computer at pin #21 if that is easer to access with your setup.

Was just looking at the manual for the LC-2. it looks a bit more complicated to connect than what I expected.

I have the LM-2 and it comes with an analog cable to connect to various signals and a pair dedicated to RPM.

Unfortunately the LC-2 doesn't seem to have this option. it appear to me that it is a dedicated O2 controller only and you will need an additional box to accept the RPM signal. in the LC-2 manual they show it paired with either a SSI-4 or LMA-3.

76F... thanks for that. The SSI-4 looks like the solution. ECU is indeed closer.