Gus

Race b - Can you go into a little more detail on the cable you made for the 3x2 coil packs -
I ditched dual ign. dizzies and went to two Bosch 3x2 coil-packs. To use these, I fabricated sort of adapetors for connecting stock ignition wires to coil-packs. They are shape of bullet, one end goes to coil-pack and then you just plug the wire to coil-pack. Rubber-part of the ign. wire fits fine to coil-pack.
I don't understand the statement "one end goes to the coil-pack and then you just plug the wire to the coil-pack " This sounds like you are plugging the wire into the coil-pack twice - One end has to go to VEMS or control unit and the other to the coil-packs - did you just splice another set of wire for the second coi-pack on to the first to run the second 3x2 coil-pack in sequence with the first. Can you explain a little more here ?
Did you use Mega Squirt or MegaSquirt II to tune. Are you running the injectors off of just throttle position and RPM - or are you using a MAP ?
I am trying to learn as much as I can right now as this looks like a good alternate to the Motronic system at a economical price-

Raceboy

Stock igntion wires fit to Bosch coil-packs (at least the rubber part, it fits snug) except they have different size clamps that. Stock wires have bigger, coil-packs have smaller. In order to get contact between wire and coil-pack you must lathe some metallic inserts (like adapters).
All this applies just to high-voltage ignition leads, NOT ignition outputs from VEMS -> coil-pack.

I use MAP, TPS is for acceleration enrichment. Gee, running pure TPS on a streetcar?
MAP vacuum line is routed to VEMS under drivers seat with additional harness and there was a free vacuum port near IAC valve.

VEMS uses it's own Megatune that is not compatible with MS and vice versa. VEMS has 16x14 tables and more features to name a few differences.

Gus

Thanks - are you really referring to the spark plug connections - where the Porsche plug wire tip is larger than the part it sticks into on the Bosch Coil Pack. So you had to mke some custom fittings. The wires from the VEMS plug inot the side of the Coil PAcks - they are OK - no changes
What was the Bosch Coil Pack part number ?

Raceboy

No, I meant igntion lead connectors to coil-pack. Porsche wires need bigger tip in the coil-pack. Compare coil-pack image on the datasheet and stock distributor without wire and you'll see what I mean.
I made custom wiring harness in order to use coil-packs because using two coil-packs requires 6 IGBT outputs from VEMS. That harness includes wires for WBo2 sensor and additional ground wires because using 6 high-current ignition outputs means that factory grounds from Motronic connector are not sufficient. If you stick with stock distributors, stock grounds are fine (stock dizzies are driven by just one logic-level output from ECU).
You can find the datasheet for 3x2 coil-pack (Bosch part no is 0 221 503 002) here: http://www.bosch-motorsport.com/pdf/..._coils/3x2.pdf

Geoffrey

Does the VEMS have built in ignitors (second stage drivers)?

Raceboy

Upon ordering, you can specify to have up to eight IGBT ignition outputs (20A each) and others will be logic-level ignition outputs. You can choose whatever combination you like(need (6+2, 4+4 etc). Additionally you can use stepper driver as logic-level ignition driver. That gives you additional four logic-level outputs (plus those eight whatever you have chosen).

Geoffrey

So, are you then splitting the ignition outputs between the coils? In other words, you have 3 channels driving the wasted spark, so you have channel 1 going to both coil board 1 channel 1 and coil board 2 channel 1?

Raceboy

No, I'm using total of 6 outputs and with each ignition event two channels are fired simultaneously, one on each coil-pack so there will be two full-power spark events on one cylinder (due to wasted spark nature). I connected cylinders like this:

CH1: 1+4
CH2: 6+3
CH3: 2+5
CH4: 1+4
CH5: 6+3
CH6: 2+5

So, CH 1 and 4 are fired together (and so are 2+5 and 3+6).

STUARTQ

This is all very interesting!