WAY better wasted spark option

[citizen_insane]

I know this is a dumb question, but I'm getting a little overwhelmed with all the MegaSquirt learning. I built a MegaSquirtII V3.0 board, used 3 BIPs to enable me to use wasted spark.

How is this wired? 3 MS outputs trigger each of the 3 coils, 4th plug is the high voltage input? Then voltage goes through the spark plug wire and ground is the cathode on the plug?

So that means this is wired directly to MS and I don't need a quad spark?

Thanks, I'm confused, and need to read the mega manual a few more times...

BIP373 replaces the quad spark. In fact, the quad spark is just 4 BIP 373's in an enclosure w/ some resistors and stuff (basically, it might be slightly more complicated than that).


The logic flow is:
MS3 Output (any allowed) -> BIP373 -> Coil -> SparkPlugs


The BIP 373 is ground switching the coil and the spark plug should fire when the MS3 is no longer grounded (goes high).



This thread is very good, make sure to read it all the way through because there are corrections:

http://www.msextra.com/forums/viewtopic.php?f=131&t=42038

This is a diagram I made based off that thread/my setup:

[McGyver]

Yep, you'll need a total of three BIP373's.

I have the DIYPNP so it was a breeze to modify. Had the board modified and coil wired up for a test start in about an hour.

I know this is a dumb question, but I'm getting a little overwhelmed with all the MegaSquirt learning. I built a MegaSquirtII V3.0 board, used 3 BIPs to enable me to use wasted spark.

How is this wired? 3 MS outputs trigger each of the 3 coils, 4th plug is the high voltage input? Then voltage goes through the spark plug wire and ground is the cathode on the plug?

So that means this is wired directly to MS and I don't need a quad spark?

Thanks, I'm confused, and need to read the mega manual a few more times...

[nando]

Nice!

Still haven't had to touch my COP setup once in like 7 years. So yeah, it's "fancy" and "complicated" but I haven't had to think about it since I put it together.

Actually, my E30 has had wasted spark/COP longer now than it had been stock under my ownership. I'm pretty sure I put in at least 4 cap and rotors, plus a set of plug wires, and God knows how many sets of plugs prior to that..

[mrlucretius]

My wasted spark build

Hey,

Thanks for this thread.

I went ahead and built this system.

It turns out I did not have to drill any holes in the chassis to mount it! There was a threaded hole, and a through hole I was able to use, it was just luck that the brackets and my design just happened to line up to those stock features.

The only issue I had was that the MS2PNP docs had the A + C outputs backwards! I was able to swap the wires for 1+6, 3+4 cylinders on the coil pack and she starts right up.

Read the PDF for the coil pack. I set dwell 3.4ms and duration 1.7ms based on my ~13V nominal voltage and an 8 amp limit on the QuadSpark.

See some photos here:

https://www.r3vlimited.com/board/showthread.php?t=409986

Thanks!

[2002tiiguy]

Pin 4 is positive, 3 is 1/6, 2 is 2/5, 1 is 3/4

[Jaxx_]

Dead thread revival lol... I'm using this set up wired to my whodwho megasquirt. I'm sure this will illicit "if you need to ask then you shouldn't he using it" comments but I can't get it running. From what the wiring says, pin 1 should connect to ign3, and so forth? What should nominal dwell be? I'm sorry if these are dumb questions, I'd just like to get it running

Wiring will depend on your application, and I don't know enough about the PnP setup to say. Keep in mind that the megasquirt pulls ground on the coil, so ensure that you have 12v at the coil when the car is in start and run. Technically, even if you have the coils wired incorrectly, you should be able to swap ign wires around to get the car to fire. Because it is wasted spark, make sure to keep each cyl pair matched to each coil.

Dwell depends on the coil--start with 3.5ms and go up in .5ms increments if you have spark issues. Some coils(like LS) like lots of dwell and can ask for 6ms without deterioration of the coil, and no increase in spark power.

Check out this video for some practical experiments: https://www.youtube.com/watch?v=C1WH0OExQyA


I'll mention because it might also be relevant for you: if your coil is hot to the touch (not just warm from underhood heat) you might have the dwell set too high, or incorrectly--going high/inverted vs going low.

[Doorgoo]

Dead thread revival lol... I'm using this set up wired to my whodwho megasquirt. I'm sure this will illicit "if you need to ask then you shouldn't he using it" comments but I can't get it running. From what the wiring says, pin 1 should connect to ign3, and so forth? What should nominal dwell be? I'm sorry if these are dumb questions, I'd just like to get it running

[nando]

i still dont get the point of wasted spark

let's put it this way, since I ditched the stock ignition setup back in 2007 I've spent exactly $0 on caps, rotors, and other stuff that seems to need replacing every couple years.

Even my full COP setup cost less than one Cap & Rotor and that included new plug wires and 2 spare coils.

[LowR3V'in]

one negative is it looks ugly as hell if you have a huge coil sitting on the valve cover :( so if you do it mount it somewhere else

What about multiple single coils?

[potatomash]

I use Mitsubishi GTO coils on mine haha, pretty cheap and reliable using off the shelf coil wires

[digger]

if you dont have any actual ignition issues then all these fancy coils, ignition boxes, blah, blah etc will do next to nothing tangible unless you are really pushing the envelope with high rpm or high cylinder pressure.

from a NA perspective the only positive thing ive seen with wasted spark is it allows you to easily add a cam sensor in its place for fully sequential injection , yet to see much in the way of benefit of sequential injection except nicer idle but will probably getting a better ECU soon to properly explore injector timing.

one negative is it looks ugly as hell if you have a huge coil sitting on the valve cover :( so if you do it mount it somewhere else

[ForcedFirebird]

i still dont get the point of wasted spark

I've been shocked many a times by both, and that alone will tell you the difference, ha! The stock single coil is what, 40,000v having to fire 3x per engine revolution, vs having three 40,000 firing once per rev. The fact that it's wasted spark is just an easy way to package, use less ignition components, plus you get the benefit of capturing any power potential of un-burnt fuel.

[LowR3V'in]

Even if you don't really GET it get that you can use powerful coils and get to run a shit ton more duration.
unstoppable spark plus total and complete burn time is where it comes down to.

also, ya. So you ever look at ur chewed up cap/rotor and wonder if it's time to replace it?

[keyland]

Theoretically, less loss in spark energy due to no longer using a distributor... Also there's no cap/rotor to wear out or break.

In my case, I did it to clear room for down pipe and/or wastegate and because I like working on electronics. Plus this Bosch coil was 1/4 the cost of a distributor cap.

[downforce22]

i still dont get the point of wasted spark