REVHED

Why would the run it like that? The Microtechs are fully sequential, have at least 4 ignition outputs and are fully capable of split timing.

The split is mainly for emissions anyway. Mazda factory race teams have been running no split for years and there are papers on it from as far back as the NSU days. Firing the leading and trailing together makes the best power.

Jeff20B

iTrader: (13)

I'd have to ask the guy who set it up whether it has split or not.

Don't let Evil Aviator see your post. He says no spilt on a carbed engine can cause detonation. It's appearantly ok for EFI though. I'm like uh, ok. I try to stick to 10º

Pele

iTrader: (28)

What do ignition and fuel systems have to do with each other?

Once the gas is in the engine, what difference does it make whether it was sucked there through a carb or sprayed by injectors?

Likewise, what difference does L/T split make? If it lights off the fuel mix early, the fuel system isn't gonna fix that... The fuel's already lit...

And I thought the split was supposed to be 8 deg.

karism

I have heard of alott of people running a no split between leading and trailing.Never tried it myself though.The closest i will go is 3deg.A few years ago,i had some trouble with a carbed 13B that wouldnt stop detonating.In every gear,at 4500 rpm it would detonate ever so lightly and then keep on revving.In the end it turned out,that the l and t were firing at the same time.With that returned to 8 deg,it was running good again.

Jeff20B:I think the EDIS6 is an excellent choice for the 20B!

Lots of good info,and good questions here everyone!

slashdawg00110

Sorry. I little bit late with the pics, but here are some of the bosch coil setups from sevenstock.

rotary emotions

since the trailings are mainly there for emission-reasons you might run without them, but what's the benefit? Even if you can get the same level of power without them (or at least about 98-99%) the extra spark will at least clean up some of the mess.
Old NSU engines had single spark plugs (no trailing) so it should be possible to run a system without trailing even on a carbed engine, but again: why?
I'd still be intrested in wether or not I can have a J-109 trigered by a ECU signal.

bill Shurvinton

Yes and no...

The ignitor runs off a zero crossing signal, so you could drive it from a J109, but there are better ways. ECU controlled ignitors are better as they have the conditioning circuits for the VR signal and an input for the ECU to drive.

I'm busy knocking up some ignition only MS circuits at the moment for some boinger owning friends and it keeps reminding me that I really ought to get a proper rotary code base sorted that will do leading and trailing properly and will drive a number of of different coils/ignitors.


Soon...

Jeff20B

iTrader: (13)

Make sure it sparks both leading plugs together every 180º of E shaft rotation please.

By the way, jsmcortina said it's probably possible to get a late leading setup for my 20B with EDIS. He said the clever way is to use a multi-tooth wheel and decode it. What are your thoughts?

bill Shurvinton

Anything is possible. If you use EDIS to control timing you will either have the choice of

1. sparks every 180° (EDIS 4)
2. Sparks every 120° (EDIS6)
3. Sparks every 90° (EDIS 8)

If you want other than that, a custom code base is a better option, The sad thing is that all the hard code has been written, its just a case of me finding time to integrate it.

Mind you the MJLjr costs $35 in parts so 2 of them, one leading, 1 trailing would hardly break the bank. I need to email Renns and see how his dual EDIS is getting on.

Currently have 50 of the little sods on my dining table being assembled.

Slammed_GSL

iTrader: (14)

Ok, I have a question regarding the FC trailing coils, can you use them for anyting?
It seems that somebody has according to this picture, I'm not sure how though?
Anybody care to take a stab at it?

More shots here;
http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWA%3AIT

Hades12

I guess I am behind but EDIS is what????

Is this the megasquirt timing computer I have heard about? Links please.

Jeff20B

iTrader: (13)

EDIS is a Ford thing. I never heard about it untill I got into MegaSquirt. It's appearantly easy to do a direct fire ignition system with an EDIS module and there are a couple MegaSquirt CPU controller codes already written to take advantage of EDIS. I think renns was the first person to set up EDIS on a rotary; it currently has single leading sparks and there is no LT split, but he's keen to try dual leading sparks (late leading) and possibly some sort of split (I don't know if split is possible yet, but MegaSquirters are constantly pushing the envelope, so I wouldn't put it past 'em).

Bill, since there is no EDIS12, is it possible to get one spark from an EDIS6 every 60º? If not, how about two EDIS6 modules which share a PIP or SAW (sorry, I don't know what I'm talking about) and a diode or two on each coil so the coil outputs of the EDIS modules are electrically seperated from each other while at the same time connected to each coil negative terminal? renns mentioned something about this today, as well as using two VR sensors 180º apart on a 36-1 wheel.

I'd use three FC trailing coils or three FB diamond coils.

Slammed_GSL, speaking of three FC trailing coils, I checked out the auction. The guy made a crucial mistake in not showing the distributor. I doubt he'll get very many bids, if any at all. I wouldn't buy it. I can sort of see a couple J-109s behind the computer case fan. Check out their shoddy positioning.

Hmm, I bet that setup was inspired by my DLIDFIS article. I think it is DLIDFIS, although executed kinda strangely. Can anyone tell if that's an '80 RX-7? It might explain all three ignitors bunched up over on the fender well.

Slammed_GSL

iTrader: (14)

I never considered bidding on that junk, it was just interesting how it kinda dovetailed into the threads on ignitions and the FC coils. I have 2 of the Trailing FC coils, can I use them for anything at this time on a FB?
Thanks again for the note.

bill Shurvinton

http://picasso.org/mjlj/ shows the cheapy ignition only approach.

Firing every 60 degrees COULD be done but not really worth the effort to do it with EDIS, much easier to do with the modificed Megaspark code I never get around to finishing.

Jeff20B

iTrader: (13)

Megaspark code? MJLJ? Not worth the effort to do it with EDIS? I'm a bit confused and intrigued. Please, continue.

bill Shurvinton

MS being open source there are a number of code bases out there that came from individuals with different needs. The original megaspark code was designed to work with a dizzy, a bit like the computer controlled HEI computers GM used to do.

Then it was pointed out that you could go wasted spark using very similar code and an EDIS module, where the EDIS does all the hard timing calculations and you just sent it a pulse where the pulse width equals the advance required. This is fine for a rotary if you want to fire leading and trailing together. But if you want to run a wasted spark leading setup its not so good, as the EDIS doesn't want to do that.

So the way to go is to do a few mods to the existing MS code to allow you to use the Gen 2 CAS, as this has handy teeth every 30 degrees, which makes the code fairly easy. With this you could drive Whatever ignitors you wanted to get the sparks you need.

But here lies the rub... To drive a second or 3rd gen coil pack set requires 2 timed ouputs and a trail select line. All other ignition codes have 1. To do a 20B requires 6. You only have 1 spare hardware timer though. No problem, with the clever use of interrupts you can just sequence the timing for the different modules. BUT it requires a bit of thought in the coding and a small mezzanine, something I just haven't had the time to sit down and do over the last 18 months. That's kids for you. But the plan is to have this as a version of MS that would cover all the options that you could likely want, including cutting trailing under boost, and maybe ONLY firing trailing on light load conditions to allow more advance to see if that gives any gas mileage improvements.

I have worked out what and how to do it, unfortunately that's only 10% of the work done.

Bill

Jeff20B

iTrader: (13)

I'd like to use a CAS. I don't need to run trailing at all so at least the complication level will be reduced.

I proposed the idea of using three X outputs to control ignitors to renns and jsmcortina. jsmcortina thinks it will work with software and hardware mods. I assume a capacitor circuit would be needed to smooth the square wave output of the CPU into more of a sinewave form so the ignitors (J-109 or GM HEI) could use it.

You mentioned that I only have 1 spare hardware timer. If you don't mind, could you list them all as I thought the X outputs could be used for anything you wanted. Would they have to be set up as software timers? If such a thing is possible? Man, I suck at software.

bill Shurvinton

The outputs can be used for anything, but the 908GP32 that MS uses can only access 3 of its timer ports. 2 are used for injector driving, leaving 1 that can be used to generate interrupts for other uses. So you would have to set up the interrupt handler to know that, on the spark_interrupt you would work out which pin to twiddle next, load up the timer ready for the next spark and then get on with things.

For ECU control, sod the faff of J109s other than for signal conditioning from the CAS to the MS. Use an ignitor that was designed for the job. Use EGI coil packs and the circuitry is all there.

For you are you want something different then just grind teeth off the CAS until you have a spike every 120 degrees and use the squirtnspark code set to V6 with a few counters if you want to sequence things (actually this would work quite well, but its only a half way house for me, so I put it to one side ).