MicroSquirt.com read only forum (Jan.15,2018)

I have just ordered a microsquirt and have been looking at the installation instructions and other documentation and could not quite wrap my head arround how to wire up the dual spark for my application.

I have a 78 Suzuki GS1000 (inline 4 wasted spark)that i have converted from Points to Dyna S electronic pickups. Each pickup drives one of the 2 coils.Is it possible to have the Dyna S hooked up to the microsquirt so that i will be able to adjust my timing and get rid of the mechanical advance?

You should be able to bring in 1 pickup through each of the inputs and have Microsquirt fire the coils directly.

Flatline_Racing wrote:
I have a 78 Suzuki GS1000 (inline 4 wasted spark)that i have converted from Points to Dyna S electronic pickups. Each pickup drives one of the 2 coils.Is it possible to have the Dyna S hooked up to the microsquirt so that i will be able to adjust my timing and get rid of the mechanical advance?

From the drawing, it looks like the Dyna S electronic pickups also are a ignition amplifier, since the outputs go direct to the ignition coils. In other words the high-current drive is part of the Dyna S.

If this is the case then what you will want to do is pull the output high with, say a 1Kohm resistor, and hook this junction to the VR inputs of uS. The pullup resistor setup should provide the switching squarewave needed. However, the first VR channel in uS is set to 150mV crossing, so you may wan to use the opto input for the first channel. The second VR input trip point is higher at 1.8V, so this would be perfect for the second pickup.

- Bruce

Ok, this is my understanding of your advice, is this correct?

Here is my guess at megatune settings:

Ignition input capture: Falling Edge
Cranking Trigger: Calculated
Coil Charging Scheme: Standard
Spark Output: Going High (Inverted)

Yes, so far everything looks correct. I would give it a try...

- Bruce

I have a similar set-up. A GS1100 2 valve engine in a lotus seven clone running a Dyna S too. I'm interested in how this works out.
How many watts would the resistors need to be?

I Think that it can be a normal 1/8 or 1/4 watt resister. All that it is doing is pulling the output high instead of leaving it floating. Assuming 12v and a resistance of 1kOhm then the current through it will be 12mA. If I am wrong could someone who knows please let me know before i 'F' something up.

Thanks,
FLR

Use a 1/2 watt resistor to be safe, it's not really any/much bigger, the 1/8 watt could get warm at high revs, depending on duty cycle.

Ian.

newtyres1 wrote:Use a 1/2 watt resistor to be safe, it's not really any/much bigger, the 1/8 watt could get warm at high revs, depending on duty cycle.

Ian.

Yeah, I guess that it is better to play it safe.