931 DITC questions
 

All,

Before you read this, yes! I already know that I am crazy... That being said, here we go... I am adding CIS, Turbo, and DITC to my 67 912 with a 914 2.0 Type 4. I have a 1982 931 complete parts car. I have found very little technical info on the Siemens-Hartig DITC unit. I know it reads manifold pressure, ambient air temp, and rpms. It reads the rpms from a crank sensor on the flywheel. This is the cloudy part. Is this nothing more than a hall-effect sensor? I can get a Hall-effect sensor for my type 4 but I would need to know how many magnets are on the 931 flywheel to keep proper timing, right? Meaning, for it work properly, I would need to generate the same number of pulses at the same time. What size is the 931 flywheel anyway? If it's 200mm, then maybe I can get it machined to fit my type 4 and then use the stock crank sensor from the 931.

Try www.924.org

Good luck, take pictures!

Do a check on the 82 924t flywheel. It has two ring gears, one for the starter & one for the sensor. Teeth not magnets, I think there is a missing tooth on the sensor ring gear, not sure. As long as you run a proxsimity sensor you can run a plate on the front of the crankshaft. I don't know the number of teeth (same as flywheel) some of these places that run electromotive either fab or have a source for their sensor brackets.

drew1

As the DITC had all the reliablity of a Yugo when they were new, you find life less brain-cell-exploding by using Bosch Motronic (there are people who can provide custom chips) off a more modern car. There's not much point in using a system that is not only out of date, but is both expensive and difficult to get parts for. The other solution is to use a stand alone system, there are plenty around that will work with turbos and are easily programmable with a laptop.

Thanks for the information everyone. I will look around for a modern replacement.