3,6L twin distribuidor setup
 

Dear Friends,

I have a 3,6L engine from a 964 and since I´m planing in use ITB with a Motec/Fueltech engine management type i would like to know a few things

1-) Does both spark plugs (top and bottom) fire at the same time in a giving cylinder?
2-) Or this engine use the so called " Wasted spark" system? If so, how many pick up sensor do we have? One per distribuidor or just one pick up sensor in one distribuidor?
If so, which of the 2 distribuidor have the sensor
3-) Also how the other distribuidor knows when to fire when the piston reached the waste cycle?

Thanks

Ricardo

1. both plugs fire at the same time

2. The sensor duty is done by a pickup sensor on the flywheel. The flywheel has 60 minus 2 teeth. In other words the gap with the missing two teeth sets the reference. Once the reference is set, the DME ECU
plus the 60 teeth "knows" the position of everything and controls when to fire which set of spark plugs
There is no wasted spark. The 964 also uses sequential injection as opposed to a 3.2 motor which uses batch injection.

But.... 964 and 993 have cam sync (Hall) sensor in the distributor that allows the injection to be sequential.

It is not per distributor, ECU just needs to know which cylinder is TDC (1 or 4) and it can only know it from cam, not crank (rpm and exact TDC is for timing is from crank).

You are correct. Didn't want to complicate things further with with Hall sensor etc. Just trying to make the point that the sensors and ECU determine plug firing not just a plain pickup in a distributer

And knock control -

Actually knock control can be done with just crank also but then retard will be ignition channel based not cylinder based.

thank you all