I have pics posted in the gallery at the address below:

https://www.rx7club.com/photo/showga...hp?ppuser=28650

I'm unlikely to take it apart, but there's nothing below the top plate that's unique, anyway. In other words, you can see everything I changed from the top, without disassembly. Once all the pics are approved and appear in the gallery, if you take a look at your stock dissy, it'll probably be clear how to modify it. You'll need an add'l pair of magnetic pickups to do this, plus add'l ignitor(s) if you plan to run Alts. 3 or 4 from my previous post.

 

All 13Bs from '86+ had simultaneous firing of both leading plugs. I actually thought the 20B did too, so I took it upon myself to figure out how to accomplish it. Then after I had completed my prototype, I found out the 20B only had single leading sparks per rotor face. Heh, that makes mine unique.

Here are two pictures from the top. Sorry about the quality.

 

No, I did something more (less?) boneheaded - I put the distributor in 90 degrees off. Leading didn't care since it was MSD-driven direct fire, trailing was firing on the wrong rotor.

Man you never heard so much detonation. Apparently N/As *can* detonate if you set trailing to fire at 196BTDC.

Being too lazy to remove the A/C bracket so I could pull the distributor, I just switched the leads at the distributor cap. Then had to remember that T1 went to rotor 2 and vice-versa.

 

The time mine did that I had accidentally swapped T1 and T2 on the cap while hooking everything up after a DLIDFIS install. So in reality, I never actually tried to fire both trailing plugs at the same time, but it accomplished the same thing in the end.

I even drove it around the block like that and I think anything above 1500-2k would cause the detonation. It must have had something to do with the amount of advance in the dizzy vs how far along the rotor with unburned AF mixture was in its cycle.

 

Yep. More than maybe 1/3rd throttle or anything over 3000rpm and POW POW PEEYU POW... must have detonated 50-80 or more times before I figured out the problem.

 

I thought detonation = Dead engine.

 

Not on an NA.

 

Especially when you can't get anywhere near full load before it happens.

Figure that at the throttle settings I was probably still under 5-6 inches of manifold vacuum when it'd start detonating. Nowhere near full load.

 

Exactly; I'd barely get on it and it would detonate. I could barely get it up a short hill nearby.

 

someone please archive or sticky this!!!!

this is valuable information here

thanks guys

 

Just ordered my DIS-4 HO (The HO stands for highly overpriced There's a basic DIS-4 and then there's the HO version. The HO supposedly sends a few more electrons across the spark gap, which is better for igniting high boost mixtures. It sells for about $415, so I think that's about a dollar per electron. These things are on backorder, so I won't see it for another month. I'll post installation pics when I get my stuff.

 

To keep you up to date, the pictures in my gallery were approved, so there are more shots of my Direct Fire Dissy (DFD). I also uploaded a wiring diagram.

I've finished the mounting brackets for the coils (they'll mount on top of the engine). Next are brackets for the ignitors and the MSD DIS-4 box. More pics as I progress.

https://www.rx7club.com/photo/showga...p?ppuser=28650

 

Will you keep the two tip reluctor on leading? Or swap it with a four tip for simultaneous firing of both leading plugs? Or is that even possible with the way the pickups are stacked? Is trailing on one stack, and leading on the other?

 

The way it's set up, one reluctor is for rotor #1, and the other is for rotor #2. I plan to keep only two tips for each one.

And yes, you are correct -- one stack of mag pickups is for leading, while the other is for trailing. I don't plan to run wasted spark at this time. I set up the stacks this way so I can vary the phase between leading and trailing timing on both rotors simultaneously -- I just need to loosen a screw and rotate the trailing pickup stack.

 

Ah, I see. Well, I'm certainly a believer in wasted spark or simultaneous firing or simulspark or 0&180º sparks or whatever you want to call it. So much so that I've gotten it to work on my 20B and plan on making it work on a single rotor engine.

It's kinda funny how calling it '0&180º sparks' is probably the only description that is not two-rotor-dependant. It works from one rotor on up. Heh, nice tangent eh?

 

random question, how much do ignitors sell for anyways?

 

Elwood I could eat off of your carpet its so clean, but I would be afraid of getting it dirty.

is that the replacement stuff of ebay ?

 

$15-$20 on ebay, over $500 if memory serves me correctly from mazdatrix and other oem type venders.

 

Says I need permission to view.

 

I think new ignitors are $200-250 at the dealer.

 

elwood

I really like what you have done. I want to do the same and run a COP setup on my car. This was a great way to do it and still Keep the timing easy to set.

 

I got it from Auto Custom Carpet (check their website). There must be at least 4 or 5 big time places that specialize in replacement carpet, and the cost seems to be about the same at all of them. It comes molded, with the driver heel pad, but without any of the other cutouts. This was good in my case because my racing seats are mounded directly to the floor (no seat tracks), so I didn't need the OEM cutouts.

When I installed the roll bar, I removed the storage bins, and I glued ozite directly to the floor in that area. Lastly, I cutout a piece of ozite for the rear hatch area and had my local auto interior place surge around the perimeter.

 

Payed $150 for new ignitors at the zone.

 

Tri-Point has tested used ones for $75 ea.

 

Here's a wiring diagram for my Direct Fire Setup:
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