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

I'd like to use 4 single fire Yukon Truck coils (each with a built in Igniter) on my turbo'd bike, the coils give a VERY strong spark!

I know the new V3 uS has 2 ignition outputs & i will be using 2 ignition inputs but before i buy the coils i need to know if each output signal can be split to run 2 coils (thats 1 output signal to fire 2 coils), its a 4 cylinder bike running wasted spark.

Im asking because i know the older version's 7.5A outputs could not power & drive 2 coils, i know these circuits have been junked but im still not sure if it's ok to 'split' the signal.

Yes, it can - the current involved in driving each channel is quite low. See the Microsquirt section on driving coils; LS2s are specifically mentioned.

There has been a great deal of discussion on the D585 LS2 coils on the MSExtra forum of late, with info and experiences brought in from other vehicle forums. The 5.5ms dwell listed on the above page is considered far too long, and can lead to the built-in coil driver going into safe-shutdown mode, firing the coil and leading to uncontrolled advance. A poster uploaded the GM dwell map for these coils for some vehicle or another, and the highest value was around 4.5ms. The current wisdom on the Extra forum is to limit dwell to 4ms.

Thanks (yet again) Don

The thought just occurred - you MAY run into a weaker spark at advanced revs, especially running wasted spark. These truck coils may provide an immense spark when fully charged, but the electricity to charge them still has to come from somewhere, and bike alternators - especially on older bikes - aren't known for the sheer pulsating power of their charging systems. You may want to consider a lesser coil that - while giving a lesser spark on average than the mighty LS2 at low revs - will still give a more CONSISTENT performance as a the revs climb, the boost builds, and the wrist rotates backwards.

Good point! I had hever thought of that!!

What do you recommenr Don? (sorry as im new here i don't know what people use)

I was also pointed in the direction of this VW coilpack

I'd go with the LS1 or later VAG COPs; I can't comment on the VW coilpack - no experience. Your stock coils should work well, but as discussed previously you'd need a driver pack.

This is not my statement, its a guy called Arttu who seems to know this stuff well. He done some tests on this coilpack.

I found some notes from VW coil test. One that I tested needed 4.3ms dwell at 13.3V to reach maximum charge. So I would set running dwell to around 4ms and cranking dwell maybe 5ms

I kinda like this one if i were using something else because it needs just 1 plug with 4 wires........ +ve, -ve & the 2 ignition inputs for wasted spark. They have a built in igniter as well so no need for a driver pack..........and it's about £20

Sounds pretty good!