openshot

oh cool thanks

nick812

Ok I am getting ready to do this mod and SO many wires. I have read Jeff20B writeup and was wanting a few more pics of this setup. I am gonna be running 3 MSD Blaster coils. Has anyone done this mod with a locked dizzi? Thanks to Jeff20B for a great writeup and anyone else that has done it.

DAVID GRIMES

Wait a minute, now... I thought Jeff20B invented and tested and proposed the DLIDFIS mod ? Your post insinuates that you are the first to do this. Not that it matters to me, but... Will the real DLIDFIS inventor please stand up.

REVHED

It was more of a colaboration.

Jeffs original PMDFIS (poor mans dfis) used two coils wired in series running off the one ignitor. I tried this and found that it sucked at high rpm on my ported motor which makes sense as each coil was only seeing half the current through the primary winding. Sterling and I then kicked around the idea of running a second ignitor off the pickup. Jeff had bench tested this and it seemed to work. So I did it, it worked great and I came up with the name DLIDFIS.

As far as any of us inventing it, I think that's silly. Some old rotor head probably tried it in the 80's before the time of the internet.

NITROUS ABUSER

James Walter Merrick, earliest reliable electronic version officially documented. U.S. Patent 3,926,165 December 16, 1975. Fuelers with points and condenser based vertex magnetos and coils unofficially.

DAVID GRIMES

Oh, right. old JW ******* got in his time machine and went forward to 1979 or so and picked up some J109's and added a second leading coil to... uh, what kind of engine would have needed this mod in 1975?

We're talking about the mod to first gen RX-7. Don't be pulling some **** out yer *** that doesn't apply !

What mods have you come up with for our cars? Successful ones, I mean.

John64

Dave, don't get upset by the new guy.

bliffle

In general I'm reluctant to modify OEM systems on my numerous rotaries, but this one may be OK since it is rather easily reversed, requires no new mounting holes, etc., and might actually improve everyday performance. I have no interest in over-revving any more engines, having exploded a sufficient number when I was much younger, and being fearful of introducing the new thrill of exploding apex seals, which I predict based on my previous studies of Vibration Modes In Metal Plates which suggests that new and more violent vibrations arise disproportional to applied stress. But if engine operation is kept within appropriate constraints one should get easier starting, better gas mileage, cleaner emissions, and better torque while avoiding excess combustion chamber temps and pressures and maybe even Unforeseen Bad Side Effects.

So I'll prolly try this on my DD 85GSL and then the 85SE (which needs help because it flooded while trying to start it a couple days ago). I've got a bunch of J109s so I'll prolly use those, and I'm thinking to get the Diamond coils but I don't know what model. Anyhow, I guess I can use FC coils.

Jeff20B

iTrader: (13)

REVHED is mostly correct about the early days of DLIDFIS. I think I came up with the name though. I bench tested it around Christmas '00. It took slightly more dizzy shaft rotational speed to trigger both ignitors and I was unsure it would reliably start the engine with a less than optimally charged battery.

I presented the first poor man's ignition mod known as PMDFIS to the online rotary community in spring '01. I later presented the idea of running two ignitors in parallel around summer time. REVHED and Sterling decided to try it. It was around then that I think I decided to call it DLIDFIS for Dual Ignitor Direct Fire Ignition System. I also changed the poor man's setup to SLIDFIS because it only had a single ignitor.

Bliffle, I was once timid to try new things on my engine. Therefore I can't take credit for being the first to try DLIDFIS in a real world situation. Live and learn I guess. I was however the first to try it on an REPU. What's even more interesting is I still have yet to install it in a 1st gen. The way things are going, I'll end up installing a 20B with TLIDFIS before I do anything else.

The low speed cranking issue was not even noticed by them. It turned out to be a non-issue; if the battery has enough juice to move the engine, compression and everything else being within normal ranges, the engine will start. Heck, I even drove around with a non functioning alternator for a week. Each day the starter would get slower and slower but it would still fire up.

That holds true for J-109s. I bench tested a pair of GM HEI clones (DR100 from Autozone) and they required a slightly higher cranking speed than two J-109s. This turned out to be a non-issue as well and hasn't caused any no-start conditions on the two engines upon which I've installed them so far. One had a failing battery and it would crank, but a faulty ground prevented the ignitors from triggering. After the ground was corrected it was fine. Then the owner got a new battery and it remained fine until he sold it, at which point I lost track of it.

The Diamond coil needs to be the type for use with transistor ignition. Avoid the type that say use with external resistor as they are meant for points. I can't advise you on the use of FC coils.

REVHED

Ah no, everything I said is absolutely spot on including the name. I have a very good memory.

You didn't propose the idea. You simply chimed in with "yeah, I've bench tested that already and it seems to work" when Sterling and I started talking about it.

DavidMyers53

Whoever invented it, it works damn good!

My '83 12A starts quicker, runs better, and revs higher.

- David

REVHED

I was in a hurry this morning so I just want to add that without Jeffs writeups no one would even know about this mod not to mention all the help he's given and work he's put in. So yes, he does deserve the credit for it. RESCPECT.

David Dewhurst

iTrader: (2)

I appreciate everything everyone has added to this DLIDFIS thread. Does anyone have any facts (Dyno sheet or ?) other than the seat of the pants Dyno to support all the claims of improvement ?

Thank you ALL
David

Jeff20B

iTrader: (13)

Hmm, that's vaguely familiar. I think you're right. Before then, the only person I had proposed it to was the previous owner of the white REPU, with whom I was having a phone conversation while messing around with the wires. It's too bad both our REPUs were our daily drivers. Otherwise, there was a bunch of stuff I could have tried. Too timid back then I guess.

Hey, didn't I ask you guys what a good name for it would be? I believe a few were handed out by the various members but I settled on DLIDFIS because it was descriptive in the face of all the coming ignition experiments everybody was keen to present in those days. I wanted it to stick, and with only 7 letters, it was no more difficult to remember than a local phone number. I wrote a big old how-to article on my web page and updated it a couple times later that year and into '02.

David Dewhurst, I stopped worrying about little details like that years ago. The dyno can show improvements that you can't feel yourself. My REPU wasn't tuned right and had a restrictive exhaust built by the PO, which DLIDFIS improved noticeably. I then swapped the engine into my MG Midget project which posessed DLIDFIS, a better built exhaust and much less weight. The engine felt more powerful. Then I swapped in a rebuilt carb tuned more appropriately for my porting level and yet another higher power level was reached. Then I pulled the engine, tore it down and it was missing a bunch of chrome. An even higher power level is achievable with better housings, better ports, better tuned carb etc. The ignition was just the first upgrade of many.

If your tuning is off, upgrading the ignition will show a greater improvement in power than if it was spot-on. Of course it is impossible to tune 100% perfect for all conditions so upgrading the ignition should be looked at as just a way to get a general performance boost and not the end-all be-all (or how ever the saying goes). At the time, it was such a dramatic improvement on my engine that even if others didn't notice as much of a difference, I still felt it was worth my time to spread the word. (Still do - these are the longest posts I've written in a while)

NITROUS ABUSER

Please get upset, PLEASE? James Walter Merrick worked for most of all the auto manufacturers for 40 years including the firing of two plugs per combustion event way back in the early seventies, he is "the man"... MAN. J109 ignitors, J109 ignitors...blah, blah, blah..."Control Modules". That is what they are, nothing more, nothing different except they are Mazda pieces. Electronic ignition Distributor with remote mounted coils and two pickups, regardless of the engine configuration...nothing special. Successful Mods...lol, LOL, LOL!!! Your welcome. Adios and Happy birthday. Your welcome Bro, and much success to you and yours in the new year.

DAVID GRIMES

LMAO. Got ya !

Again, that patent has to do with capacitive discharge multi strike and duration... which has nothing to do with the DLIDFIS mod that this thread has as its subject.

You and yours, too.