I'm need of some clarification, I have a 1974 1.8 L with a current Bosch distributor (0 231 181 009). I have two vac ports on my throttle body , one that goes to the distributor (vac retard) and one that comes from the distributor (vac advance) back to the throttle body.

My wife gifted me a 123ignition with blue tooth to replace what I have. I told them it is for a 1.8 Liter engine (L-Jetronic Bosch Fuel Injection). They provided my a new 123/TUNE that was designed for my current set up. The new Distributor has a vac hose port on it. My question is that I had a vac box on my old distributor that had one hose coming from the throttle body and one coming back to it from the distributor. Now I have to figure out which hose I should connect to the new distributor and which hose shall either be plugged up or just left open and not connected to anything. I guess I'm missing something maybe???

I 've read here that there are some 914's that have one port or two ports on the throttle body (possibly due to CA emissions and an EGR valve). I was really looking forward to adding the new electronic ignition with Bluetooth tuning, but I'm not sure to set it up correctly.

Any ideas? Thanks.

You can use either the retard or the advance port of the throttle body hooked up to the distributor (or neither). Just plug up the one not in use and set the 123 curve accordingly. Just don’t plug the port on the distributor if you leave it disconnected.

Make sure you time the engine correctly by setting the advance on your timing light to match the advance of the 123 (22 degrees I think).

Great. thank you I will do that.

I run mine with no vacuum advance or vacuum retard,

Lots of debate on this topic.

Porsche added the vacuum for emission reasons.

So plugging both ports on the intake manifold , and leaving the port on the new distributor open would be another way to go without messing with performance?

I wonder about this on the 123. My guess would be that the 123 vacuum advance/retard feature is accomplished via software and not a vacuum diaphragm that is mechanically connected to a plate like a conventional distributor. Can someone verify this? And if so it would not be a bad thing to plug the vacuum port on the 123...correct??

On my car I do have a vacuum hose connected to the 123 but have it disabled via software by setting the vacuum advance/retard to zero.

I too thought that everything would be accomplished via software tuning, but then I started wondering why the 123 mentions the "optional" vac port on the dizzy, but has no mention on how to tune it "if" using vac hose attached. Additionally, I would expect them to provide a "cap" for the port on the 123 if not used. At least to prevent moisture to get it. IMO...Thus my confusion deepens...