Stack Cluster Tach signal

[5:04]

Hey guys,

I'm installing a Stack ST8100 cluster into my car. The tach signal says to pull from the negative terminal on the coil, however it doesn't seem to be working. Anyone have any experience with this? I'm going to call them on Monday, but if you have any ideas feel free to share.

As a side note the cluster is awesome. I've run into a couple issues including the tach signal and the harness being too short. Not a problem for the oil temp gauge, but the pressure sensors have special plugs that I'd like to avoid cutting if possible. I'm going to see if Stack offers a cable extension on Monday before I start cutting.

Thanks!
Amir

[5:04]

anyone?

[304065]

what car?
what ignition system?

[5:04]

'76 911S and the factory original permablue cdi

[304065]

76 911s had a three pin bosch CDI
permatune is not original

attach the tach lead to the points terminal on the side of distributor
don't forget the ground
this produces an 11 volt square wave

You would absolutely never put anything on the side of the coil in a CDI ignition car, that is a 460V (or whatever the permantune's capacitor charges to) pulse with a ton of ringing and intereference. Hope you didn't blow up your STACK box by doing that.

[KTL]

You're going to find that every wire going to the engine is going to be too short. Autometer gives you a lot of wire (8-1/2 ft) to cover most applications. Unfortunately 8-1/2 ft. doesn't cover a rear engine car like the 911. I have a Sport Comp II pro control oil temp gauge and an Elite fuel pressure gauge. I think they're kickass.

They're just like the Stack stepper gauges because Autometer acquired Stack back in 2007. My next buy will be a nice Elite oil pressure gauge that will make all sorts of colors depending on what I set the high and low alerts for. I love gauges.

I have:

Autometer Pro Comp 9K memory tach
AEM wideband AFR analog gauge
VDO cyl head temp
VDO volts
Autometer Sport Comp II pro control peak & warning oil temp gauge
VDO mechanical oil pressure with separate warning light (20 psi or below turns on)
Autometer Elite 0-15 psi fuel pressure

Next and final two gauges will be an Elite oil pressure and a Sport Comp II trans temp.

[5:04]

Originally Posted by 304065

76 911s had a three pin bosch CDI
permatune is not original

attach the tach lead to the points terminal on the side of distributor
don't forget the ground
this produces an 11 volt square wave

You would absolutely never put anything on the side of the coil in a CDI ignition car, that is a 460V (or whatever the permantune's capacitor charges to) pulse with a ton of ringing and intereference. Hope you didn't blow up your STACK box by doing that.

Thank you, I'll try it that way. Fortunately the Cluster still works. I guess I'll find out if the tach works when I get it wired correctly.


Also as a side note. The 3 pin permatune has a Porsche part number on it and for a short run they were used by factory.

(Permatune 3 Pin box , factory in 1975)

Originally Posted by KTL

You're going to find that every wire going to the engine is going to be too short. Autometer gives you a lot of wire (8-1/2 ft) to cover most applications. Unfortunately 8-1/2 ft. doesn't cover a rear engine car like the 911. I have a Sport Comp II pro control oil temp gauge and an Elite fuel pressure gauge. I think they're kickass.

They're just like the Stack stepper gauges because Autometer acquired Stack back in 2007. My next buy will be a nice Elite oil pressure gauge that will make all sorts of colors depending on what I set the high and low alerts for. I love gauges.

I have:

Autometer Pro Comp 9K memory tach
AEM wideband AFR analog gauge
VDO cyl head temp
VDO volts
Autometer Sport Comp II pro control peak & warning oil temp gauge
VDO mechanical oil pressure with separate warning light (20 psi or below turns on)
Autometer Elite 0-15 psi fuel pressure

Next and final two gauges will be an Elite oil pressure and a Sport Comp II trans temp.

All of the wiring was way too short. I just placed my order for the extender wires though, so I should be in good shape.

I would agree on gauge love. The Stack offers rpm, fuel pressure, oil temp, and oil pressure. Then I have an aem Uego and a CHT gauge on the side. I'm kind of paranoid when it comes to keeping the engine in ideal running conditions haha.

How did you wire your tach?

[KTL]

They make harness extensions? Dang.... I just cut and spliced my temp gauge sender wires. At least I soldered the splices.

My tach hookup was easy.

Red = 12V switched power with inline fuse

White = lighting I joined this with red since mine is a racecar and I don't care if the lights are always on

Black = ground

Green = tach signal wire. I connected this to the black w/purple which was a wire in my original Porsche wiring harness. I found the black/purple wire was routed to the TACH output terminal on my Electromotive ignition board. Not sure if that black/purple is the same wire used to get a signal to the factory Porsche tach