single coil vs waste spark vs seq.

[CTX-SLPR]

Can you run the Gen III/IV coils with power to the control side (5V TTL) but no power to the 12V side? Reason is it's simpler to control a group of 3 (4 for the V8 guys) coils through the power side when occilating back and forth between different "banks" of coils if the ICM drives a waste spark but you have all the sensors (but not the ECM) to control sequential.

For example, my OBDII controll 4.1L Buick V6 uses the stock L67 ICM that fires the GM twin tower coils. It's been proven by several people that running a sequential/distributor ignition system is worth power. Theory is that firing one set backward, strap to electrode, doesn't light the mixture off as well and the chamber design doesn't do any favors to the system either. Since the ICM controls the coils in 1/4, 6/3, and 5/2 pairs, use the ICM signal through a regulator to drive the TTL side but use the cam sensor sync to control if it was the 1-6-5 "bank" or the "4-3-2" bank. Following?

[dieselgeek]

I follow, but I wouldn't be brave enough to try that with a coil that wasn't designed already to work that way. I'd be worried about coil charge time and how much dwell to run, and a few other concerns. This leaves us a few choices of OEM systems that were switched this way... but nowadays, it's so cheap to do a proper wasted spark or sequential ignition, its simpler to do the extra work in an ECU versus outside.

I kinda doubt the guys that believe a wasted spark system loses power over the distributor system, especially with forced induction. That's just based on my experience and gut feeling. What testing was done to determine this?

[CTX-SLPR]

I follow, but I wouldn't be brave enough to try that with a coil that wasn't designed already to work that way. I'd be worried about coil charge time and how much dwell to run, and a few other concerns. This leaves us a few choices of OEM systems that were switched this way... but nowadays, it's so cheap to do a proper wasted spark or sequential ignition, its simpler to do the extra work in an ECU versus outside.

I kinda doubt the guys that believe a wasted spark system loses power over the distributor system, especially with forced induction. That's just based on my experience and gut feeling. What testing was done to determine this?

Unfortunately I don't have time to dig most of the threads up on www.turbobuick.com, but the general concensus is that the stock system (Magnavox 6 tower monolithic coil and module) doesn't keep up with getting the mixture lit with larger than 0.030in plug gaps at elevated boost levels. It might not be the waste spark as much as the poor performing coils and modules but the same car with a stock type setup on FAST DFI or XFI picks up power from going to a distributor. Similarly some of the guys that run in the "stock" class that requires the use of factory parts have put together a pair of the stock system so both plugs fire "forward" and picked up power as well.

Interestingly the 3800 Series II/III guys don't seem to have this problem but the chamber design on thier heads is better and in general they don't run as much boost.

Really wish I could dig up more concrete stuff for you but this is the thread that keeps me interested in my ideas (and not spending $500 for something that isn't designed for the 3800 style ICM either)

[seanm]

Hey guys back on this again. Decided to go with COP over the quad towers. Way Overkill for now. But will be nice if the boost goes up and/ or it is switched to Methanol

Starting the mock up.

[TheSilverBuick]

[thewookie]

So scott on my 2.3 Im running the crank trigger and ls2 heat sinked coils in waste spark, I guess I should get a cam sensor and make it sequential? IS that possible with my ms1 emspro? Especially if the goal is to do drag week with alot of street driving?

chris

[milner351]

Great stuff here guys - thanks for the education.

Sean - what have you decided to do with the distributor? I guess you can just remove the cap rotor and advance mechanism - and fab up a little flat cap to put over it to keep debris out? It would be several inches shorter that way with no cap, but still be there fully intact for oil pump drive duty.

[Bob Holmes]

If that's a 2.3 ford, they make a plug in cam synch. They came oem in late 2.5 Rangers.

[seanm]

Not sure on the distributor. Will cut it off and cap it somehow. There is a guy that has done it to a Cadillac, trying to contact him now. Was even looking into how to drive a mechanical fuel pump from that end of the distributor.

[thewookie]

If that's a 2.3 ford, they make a plug in cam synch. They came oem in late 2.5 Rangers.

Yeah im aware, just wanna make sure my ms1 based system will handle it ...

[seanm]

Finished mounting the coils. Now to figure out the wiring.

[Matt Cramer]

Yeah im aware, just wanna make sure my ms1 based system will handle it ...

Sequential ignition, yes. Sequential injection, no.

[TheSilverBuick]

Looking wicked Sean.

[dieselgeek]

Wow, those look great! Sean, hit me up before you power them up, I can show you how to double check a few thing so you don't melt them down by accident. Also, the relay that powers them needs to be triggered by your Fuel Pump Relay control coming out of the Megasquirt. Not the ignition switch.

[seanm]

Thanks guys.


Scott, I'll definitely be in touch with you before powering it up.