Accuspark Black box adjustable advance curve

[billwill]

Sounds good so far.

[Johnfm]

Looks like a good bit of kit.

Why did you set the static advance to 10 instead of leaving it at zero and advancing with the black box? Is that a bit of a failsafe, in that you will have the advance if the BB fails?

I am going to buy this tomorrow and give it a go. At ?99 it is a cheap method of tuning spark timimg and setting an electronic rev limiter.

[oldchieft]

Can someone who's knowledge is not stuck in the stone age educate me?

I would like to get one of the new style coils from a scrap yard and drive it with that Stealth Black Box.

I remember that the old Honda bikes had two sets of points and two double ended coils.

How does a four terminal coil fire? Does it fire at TDC and BDC on each cylinder?

My idea would be use the pointsless distributor (mine is a LUCAS AB13 set up) this would trigger the black box.

As my Morgan got fired up in the worst possible way by the toxic mix of Webers and distributors, I am keen to follow Jono and sort the system into a safer way of working for when I fit the twin cam.

Regards and thanks for any help.

Jon the Chief

[billwill]

Read the website page that I pointed to in the first message on this topic:
free-parking-f45/modern-engine-management-systems-t29460.html

It tells you all the basics of wasted spark ignition and electronic fuel injection.

~~~

Not at BDC. In wasted spark ignition they fire at ALL top-dead-Centres including the one in which the valves are open & there is no significant fuel mixture in the chamber.
The 4 terminal coils are interesting in that the useful spark is earthed through the wasted spark.
Seems to me that it would be less reliable, but evidently the plugs are reliable enough.

[oldchieft]

Sorry Bill I see it has been asked and answered, so the coil packs are like the old Honda bike coil but two in one unit, so it will need two inputs to fire them.

The Stealth box is good value.

My Micro Dynamics soft cut rev limiter has stopped working and I have only had it 30 years, stuff just an't built to last nowadays.

I will get a Stealth as it is cheaper then a new rev limiter and I get a lot more for my money.

Regards

Jon the Chief.

[Johnfm]

Well

All installed - electronic ignition and black box.

Managed to get software to communicate with it.

Like it when an installation works!

Now to get the carbs back on and fire it up...

[miked]

Got mine! Also went for the deal on the 43D wired down Dizzy, although I have one fitted (can be the mechaical spare backup in case anything goes wrong).

Stealth now has USB power to the box so you can program it in the house on a PC without the need to have a 12 volt supply. Not fitted yet, just playing with the numbers. I notice it has a feature called RPM SYN. This is the figure the box takes over at. Set above cranking speed but below tickover. Set at 400 rpm. I was toying with the idea of including the static setting in with the curve to give a final plot starting from the static advance. Thinking about old cars bucking back and having advance and retard adjustment for ease of starting on the cranking handle, it may be an advantge to have a TDC (or thereabouts) spark while cranking and getting away to the cut in point above 400 rpm when the static advance is introduced.

Does this make sense? Thinking about it, if it only cuts in at a firing and self propelled RPM above 400 you would only have the static on the DIZZY or whatever you dialled in the black box under 400 rpm. From reading the other thread I believe most were going for next to nothing on the dizzy position and having a bit on the box to allow some overall adustment. ???

Mike

[billwill]

From what I remember reading, the dizzy has to be set retarded (?) (relative to non-accuspark position) because the accuspark actually works by advancing from the initial position and can't go the other way.


Or is it completely the other way around, that the locked dizzy has to be set to the maximum advance and the accuspark actually retards from that position. That would make the computer logic simpler.

[miked]

Bill,

It can only go in one direction - advance. You can leave some dizzy position advance on it if required and can add your advance graph/plot in the software. You must need the strobe light at the beginning as the box only drops in series with the coil and advances relative to the pulses to equate rpm. It has no idea of TDC as there is no other sensing feedback. It says you can add up to 9 degree of fixed advance in front of your plotted graph within the software screen. I will see more when I strobe up and fit it and can play and see the effects with the static. I tend to time up a refitted dizzy initially by spinning on the starter with the plugs out using the strobe. It works a treat and you are not attempting to start with too much advance or having to put voltmeter on. I was wondering more about the ease of starting with less advance and that cut in feature. It sound to be advantageous to get away firing with less advance and then introducing when RPM builds. I will report back. I liked the idea of the graph with the static included to see total setting rather that a lump of fixed advance and the dynamic bit on top. I suppose all the boys with the modern module map stuff must be up against the same thing when they program in their curves. That part must be the same as in this bit? It says to start with 0 degrees of fixed advance. Like I say, I should get on with it and stop wondering.

Mike

[oldchieft]

I tend to time up a refitted dizzy initially by spinning on the starter with the plugs out using the strobe. It works a treat and you are not attempting to start with too much advance or having to put voltmeter on.

Exactly the way I do it, the old way with a lamp or volt meter worked fine with points, but with hall effect or magnet switching static timing does not work.

Jon the Chief

[elanman999]

Bill

Or is it completely the other way around, that the locked dizzy has to be set to the maximum advance and the accuspark actually retards from that position. That would make the computer logic simpler.

Yes Bill,this must be how it works as it's impossible to advance the spark to a time before the trigger.

In normal ECU's you set the trigger to say, 90deg (crankshaft) BTDC. The map reads in advance BTDC. This time delay is required for the ECU to think.
I suspect that the Accuspark does the same thing but they are not telling you this.
If I were setting one up I would set the map to a constant 10deg BTDC then adjust the timing to be 10deg, when checked with a strobe using the software advance and/or turning the dizzy. I would then only change the map. I assume you can store the maps on the PC?
Just my take on it.
Obviously I could be talking total BS.
Cheers
John

[billwill]

Heh Heh.

Mike & John completely opposite here.

As a computer programmer I can see that it is easier if the trigger pulse is set at maximum advance, so the software just has to delay the firing of the spark, but on the other hand I have a sneaking suspicion that it needs to calculate the RPM anyway in order to define the duration of the spark current, so if it does that it can actually trigger from the trigger pulse that would have belonged to the previous spark-plug in the simple contacts+coil system.

[miked]

Very interesting. I see what you mean John about impossible to add delay to something before it has happened. This had never crossed my mind before. I think Bill has hit the nail on the head about using the previous spark plug pulse an adding delay. That makes logic sense. Anyway still without a laptop but I went out and fitted it today.

Wired the box in. Has zero fixed advance in the software. Also put a curve in that suits the weber TC. From PC - indoors.

That cut in businesses I mentioned prevents it from doing anything until it sees RPM above cranking speed. I fitted the wired down (locked) dizzy and removed the plugs and timed it a spot on TDC spinning on the starter.

I then put every back and started it so I know it has no dizzy position advance or retard. It started and I had a look with the strobe. Advance looks as per the plot. I have not run this in yet so was not going too far.

So it does do what is says on the box. Laptop coming in the morning so I will play with the fixed setting and also have a bit more of a play with the curve to see stuff move about. Took it around the block a few times and it runs fines. It is short of initial advance and is dull until 2500 ish. Will sort in the morning pending the weather. I am impressed.


Mike