Need some new coils because your old ones are just worn out?
the insides are rusted, outsides rusted and dented, just dont seem like your getting good spark any more???


Still babling about the direct fire setup your going to build thats gonna beat my msd setup ?

Heres one for the budget guys (a.k.a just about all of us)

Hunt down a 2nd gen trailing ignition coil (thats right trailing not the leading, where not doing direct fire here) either on ebay or at your local junk yard.
Either place will have them cheap since most people opt for the leading coil to use in a DLIDFIS setup.

Now when you get it home break it down in 3 pieces ( stop banging it against the table and get a phillips screw driver).
There will be
1- the ignitor
2- #1 trailing coil
3- #2 trailing coil

Now simply hook the 2 coils up in place of your old ones, for mounting your on your own.

The top of each coil is labeled + and -
For the stock wiring the big black with white stripe is your +.


enjoy

 

I have thought about doing somthing like that, but have another trailing coil fire like the leading; so you would have two trailing coil packs one coil for each plug. I don't see why that would not work.

 

Someday, months from now, I'll know what you're saying.

Until then

 

leading coil, trailin coil wtdiff?

 

Someday, months from now, you'll probably kill your J-109 ignitors. Switch to GM HEI ignitors because they're cheap and can probably more easily take the load of those trailing coils.

 

Can you switch to the GM ignitors without making mods?

 

what is the difference i dont understand is the a pro to this so i am going to replace my leading and trailing coils with 2 trailing coils??????????????????/

 

1985rx7, sure, but since they are shaped differently than the J-109s, you'll still have to fab up an aluminum backing plate for proper heat-sinking, like this.

One for trailing, and two for leading (one for each coil). Leading is direct fire and trailing is still through the cap. They typically come with white thermal grease in a small squeeze pack.

Fuel524, no, you will be replacing your stock 1st gen leading coil with two 2nd gen trailing coils. The reasons why are because they are typically left on the car after someone has removed the leading coil, so they're cheap since there's little demand for them. Also, it allows each leading spark plug to have its very own coil for improved performance all throughout the RPM range, faster easier starts, better gas mileage, etc.

The only problem that I can think of with doing a mod like this is that I've never done it before, so I can't instruct you on how exactly to do it. I can however say that V8kilr is on to something. Heh, those trailing coils typically are left in the cars, aren't they.

 

Try it and find out why you cant.

heres a hint though, wasted spark on a trailing plug introduced on an intake cycle is not good.

 

Or you can just get another set of J-109's off ebay for around $10.

also I would like to point out that he's not saying you will kill your ignitors from doing what I posted above.

 

Well first you need to ask yourself why are trailing coils trailing coils?

is it because
a- there manufactured differently to be specifically used on wankel motors for the trailing ignition
b aliens dropped them off to mazda for use on the rotary and rotary only
c- There packaged differently so people will know where they go when installing, uninstalling or diagnosing them but internally the same


Ill give you a clue, its C

now re-read my first post to understand why I mentioned using them.

 

Yeah they are, thats why I say go for them over the leading if all your looking for is a slight upgrade and replacement.

As for the ignitors I would rather grab a MSD 6AL and use it in place of the J-109 in terms of upgrades.

 

I know alot of you are farely new on this forum so in case your like when I say my DF setup heres some old pics

 

 

I could tell they were old pictures because you forgot to move your trailing wires over to the leading part of the cap.

 

lol, yes sir it was right when the job was completed, had'nt even drove it yet when the pictures where taken

 

 

I have right in front of me both a leading and trailing set of 2nd gen coils, and definitely in a dillemma of how to use them. Just wiring up wasted spark using the leading coil would be incredibly easy, but can it make the power that the dual coils (MSD, diamond, or stock 2nd gen trailing coils) can potentially make? Seems to me the 2nd gen coils are big and bulky and odd to mount in comparison to the leading coil or MSD/diamond coils. I already have 2 MSD Blaster 2 coils, but will return them if I use the 2nd gen leading coil setup. Anybody used both setups and compared? I do know one thing, if size matters, the trailing coils are each bigger than the leading coil.

 

If I were you, I'd use the 2nd gen leading coil instead of two coils because what happens when you wire two loads in parallel? The available amps goes down 50%. The MSD has a finite output which is high in voltage, but low in amps. Think about it; it's converting 12V to something around 400V.

I have personally tried the MSD on two Diamond coils and it was a ho-hum mod. Then I tried DLIDFIS and liked it a lot better. I have not yet tried the MSD with a 2nd gen leading coil, but I've got one sitting here.

Hmm, here's a thought. I could just go ahead and do a couple ignition experiments today. I've got two J-109 ignitors that seemed to be dead yesterday. I just need to double check them in a controlled environment. I could also do an MSD with two diamond (or Bosch OEM replacement) coils vs a 2nd gen leading coil. I'd also like to figure out how to hook the 2nd gen leading ignitor to a 2nd gen trailing coil for use on the trailing side of the ignition. If I can get that to work, I'd be out $0 for my next engine's ignition system.

There was a diagram somewhere out there that I will try to find...

 

Here is the block diagram I mentioned earlier. RX-Midget made it. This is how to use a 2nd gen leading ignitor on a 2nd gen trailing coil for use on your trailing ignition (or leading in a pinch). It's what I'll be refering to, and if I can get it to work, it's what I'll use on my next engine.

 

If I was going to use the 2nd gen trailing coils, I would run each through its own ignitor, just like other direct fire types. But I am going to use just the 2nd gen leading coil and see how it goes. Probably hold on to the Blaster 2 coils and try full DLIDFIS later.

 

That sounds like a great idea. Yeah, those FC trailing coils coupled with FC leading ignitors sounds like the ultimate DLIDFIS so far. The only problem is the parts it requires, which for some, may not be a problem at all.

The key is giving each coil its own ignitor. For example, since the MSD is rather expensive, this doesn't make much economic sense to buy two (one for each leading coil), but it would work great at low RPM with all the multiple 13kHz sparks near idle and so forth of unshared power. It probably wouldn't have that 8k RPM bug that people with one MSD hooked to two coils used to mention, either.

Those 2nd gen leading coils are even ok on high power 20Bs with the E11 or other aftermarket ECUs set up to fire leading and trailing together. I'm not sure if they require the leading ignitors as well, or if 20B guys typically get MSDs or whatever. I was just going to run three J-109s and three Diamond coils for leading only on my NA 20B so it'll have the power of a T2 but last forever. It'll have 0º and 180º leading sparks every 120º (figure that one out) and won't need that Racing Beat custom perspex cap and modified rotor with reluctor. Trailing is good for a tiny amount of HP, tiny amount of reduction of emissions, and can even help with fouled leading plugs, to help the engine start easier (actually, when my leading ignition was messed up, the engine would not start on trailing alone, so maybe that theory isn't as wonderful as RotaryDankus made it out to be). In other words, trailing isn't really necessary at this point.

That's a little off topic, so back to the subject. I'm going to start working with my 2nd gen coils and stuff in a few minutes. I'll update this thread when I've gotten some results.

 

Better yet, does anybody know if both 2nd gen trailing ignitors could be hooked to the same pickup like 'classic' DLIDFIS? I'm asking because it would be easier to use the two trailing ignitors that already come with the trailing coil assembly rather than sourcing two leading ignitors and then not using the leading coil for anything.

Does anyone know if the trailing coil assembly contains two seperate ignitors? I'm going to mess with mine right now. It's missing one trailing coil, but the ignitor box looked intact the last time I looked at it.

 

Jeff20B, those questions and statements about the FC coils and integral ignitors are exactly what i thought the direct fire mod was.

I did a bit of reading through past posts, and I wonder as well if the trailing ignitors and coils would work. While you are at it, i wonder if it would be worthwhile to add the FC leading coild and ignitor as well.

What about the FC distributer/pickup? I pulled one apart, and it appears to be a magnetic/hall effect device, which might be able to perfectly drive the FC coil and ignitor sets. Any thoughts on this?

 

The FC CAS basically needs an ECU. RX-Midget has messed with one to get direct fire trailing, but I don't really feel the urge to bother with it.

The FC leading coil can be used with the leading ignitor on an FB pickup, if it;s wired up like the diagram above. Or at least it should work. I'm going to spin a dizzy with the leading ignitor hooked to a leading and then a trailing coil I'd like to see which produces a healthier spark in the atmosphere. Of course sparking under engine compression is a whole 'nother affair.

Yeah, I'd like to try all this stuff in one form or another and go with what works the best for the money and effort.