[raven361]

Awesome, thank you. I suppose that this is why you suggested to have all of the grounds from the Speeduino to one common ground.

Have the resistors on the way as we speak .

Cheers,
Nate

[raven361]

Alright, I have everything to start wiring up!!!

I do have a question for PSIG, that diagram that you put up has 2 caps for the coil packs, I plan to run 8 LS1 coils so do I need 8 25uF caps or did you add up the needed capacitance for 2 coils to arrive at 25? Similar to that question, looking at a megasquirt article, the were suggesting that you use one cap @ 1.0uF between 12V and ground and one cap @ 0.001uF between signal and ground - if I were to run 8 packs, would I add the capacitances up if I just want to run two for all 8 (one between power and one between signal)?

Thanks in advance!

[PSIG]

No, that was a bulk value for a different application and purpose. The coil capacitors are individually per-coil, as each coil is its own pulse source. So, 8 x 1µF HV film capacitors, and additional caps of other values on other power supply lines as you specifically need them.

Trivia — the diagram with the 25µF caps was an attempt to gain both coil noise suppression along with overall system noise suppression. It worked, but nowhere near as effectively as the traditional methods described for coil caps versus system caps (alternator, junction, pumps, etc). Remember, caps can make things better, but also sometimes worse in other ways. Use them specifically with planning, as random can create confusing situations.

[raven361]

Interesting and thank you. Also, I figured you were going to say that about the caps - I've had a brief introduction to circuitry during my math and physics degree, but in physics we just did super high level electrodynamics and well, the Kirchhoff loop laws were explained in a very terse fashion. (I also think that your trivia should make a geeks who drink question somewhere...)

Alright, now on to figuring out how to get these caps wired in!!!

Thank you again!

[raven361]

Forgot to ask this as well - does the Speeduino need to be wired to the starter like the Chevy TBI ECM? Or will a power source that is hot while cranking and normal operation suffice?

[theonewithin]

Just hot when ignition on/cranking.

[raven361]

Thank you! It's all coming together!

[PSIG]

Alright, now on to figuring out how to get these caps wired in!!!

One common method is to simply back-probe the cap legs with crimping or soldering into the coil terminal connections. Heat-shrink a tube around it for a nice package.

[punisher454]

On a small block chevy you can use a vortec distributor (96-99) as a 1x cam sensor and use a vortec timing cover with the 4x sensor ring for your crank sensor, all OEM parts and dirt cheap at the wrecking yard. This will let you run your LS1 coils in waste spark mode and if you want to upgrade to a port fuel injection manifold in the future you'll already be setup to run semi-sequential with what you have.

[raven361]

PSIG, thanks! I'll be trying that for sure.

punisher, thank you as well! That might be a next year project for sure!