My cop setup for my 94 na

[Strider]

So this Saturday I decided to do the COP setup from miataturbo.net since my coil pack has started to go out. I got it all wired up and it started! Smoother idle and no more random miss.



I'm still going to build the aluminum plate to mount the cop and get some of that plastic shielding for the wire to make it look stock. Has anyone else on here done this or thought of doing it?

[Jiggerachi]

Very cool. Thinking of doing this myself. How much out the door did it set you back? Car's due for new wires soon so might be a good time.

How did the header work out?

[Strider]

Hey man, yeah the header worked out great. The flange that meets up with the car was warped. I had a muffler shop weld it up for me. The coils were found new on eBay for $66 and the connectors were $36 on eBay as well. So for right at $100 it's worth it. Pretty easy just don't get any of your wiring mixed up. I did and it took me 30 min to figure it out but once fixed it started right up.

if you do plan on doing it watch out for the wire going to the temp gauge. I pull it off to get the harness pulled up more and when I tried to plug it back in the pin connector broke off so now I have to buy another sensor or maybe solder the wire back to the temp sensor.

[SirHustlerEsq]

What computer? OEM with dwell-reducer?

[Strider]

OEM pc and no dwell reducer. I just wired it up without the copasitor that it suggests adding. I may still do that but so far it is running fine.

[slowchildmiata]

It should run fine until you burn the coils up!

[SirHustlerEsq]

lol @ running 60% more dwell than Toyota COPs can handle.

[Strider]

I guess I'm building myself a circuit board then. LoL I don't want them to burn up

[Strider]

I found a forum with the schematic to build a dwell reducer but it isn't laid out clear enough for me to understand what I need. Anyone on here made one or able to help me out with understanding it? I looked and couldn't find a place to actually buy one.

[SirHustlerEsq]

Contact Jason Caudra (Jason SBC I think) on Miata turbo. I think he makes them.

[gptwins]

cool upgrade!

[Rob®]

You definitely will burn coils without adjusting dwell. I burned 4 when I ran mine with my LINK, all at nearly 200 miles on the dot. Would run beautifully, get to the 200 mile mark, and I'd instantly be on 3 cylinders and sound like a Subaru. Replaced bad coil, repeated 3 more times, each at very near 200 miles.

I contacted Jason and we talked for a bit. He said he had a new idea for them. I said I'd gladly guinea pig it for him, and pay for an entire run if that's what it took, but he stopped responding. Maybe he did it on his own (I don't bother with other Miata forums) by now since this was a year or so ago.

Then I managed to find a Boundary Engineering dwell reducer. Installed, backfired and blew the garage door insulation out of the sections behind the exhaust tip. Took it apart and noticed immediately he used the wrong OPAMP. Replaced, still no worky. Started drawing the circuit he had and compared to the circuit diagram that you probably found, and saw it's a bit off. Then life got in the way, so I pulled it off the car. I'm going to just remove everything he installed on the board and start from scratch using the board and case from him with all new parts. I have the parts, just not the time. One day. If I don't ditch the LINK first.

[Strider]

The only reason they go out is from over heating right? I noticed that the one in the back was the hottest by touch. I was thinking about maybe buying some heat sinks and putting them on the top with some silver light inbetween. Think that might help with the heat? would deff look weird. Haha. I can build the circuit board if I knew the meaning of all the different parts. I know basic automotive stuff but anything past resisters and switches I get lost. I believe I have past the 200 mile mark. Just finished my first tank of gas. I looked at the coils today and they didn't look burned on top.

[Rob®]

Few things:

1. They over heat from too much dwell. So technically, yes, they "only fail from overheating" if we're going for broad statements here. Heatsinks could possibly drag the inevitable out longer, but kind of doubt it (you'd be attaching the heatsink to the outside of the coil, not the actual parts that overheat).
2. The dwell reducer really is about as basic a circuit as you can get in a real world environment. What is confusing you, exactly? (I apologize if this sounds condescending...it's not meant to)
3. The 200 mile mark is specific to my car, and my car only, as far as I am aware. I think it was just the fact that I was only driving the same exact routes each and every time, and in just about as close to the same exact manner as possible. So the 200 mile thing is by no means a benchmark: it is purely my firsthand experience. Four times, oddly enough.
4. I have boost. Lots of it. And my redline is 7700RPM. None of which help the too much dwell situation at all. A stock naturally aspirated Miata driven like a normal commuter car might never burn up a coil. A lightly boosted one almost certainly will since you'll most likely rev the car like you should. A high revving driver, boosted or not, will burn them up for sure.
5. None of the four dead coils I have look burnt or otherwise bad. They all just stopped working (and were dumb hot right when they died). If I put them on a shelf next to fresh ones, you wouldn't know which was which.

[Strider]

here is the link I'm getting the schematic from http://forum.miata.net/vb/showthread.php?t=277963

I have found a board similar in size to the one he is using and I found the TS914 op amp on ebay.

As for the schematic I'm just unfamiliar with some of the symbols. I understand that R1,R2 and so forth are the different resistors and J1,J2 is junction points I think. I just don't understand what the triangle symbol is with the line down the center and the rectangle looking boxes. I also don't understand exactly how the red lines on the one schematic are supposed to link everything together.

[Rob®]

The Js are where the physical wires will attach to the circuit board (the wires that will be spliced into your harness). You'll see below there are two of each numbered Js: one is a relief hole to run the wire through to avoid damage, the other (inner most hole) is where the wire actually gets soldered.

The triangles are the OPAMP. There is only one, but since there are 4 separate circuits (one for each coil pack), it shows up four times in the diagram. A quick Google of what an OPAMP is should give you more details than I care to type here. They are much more complex sounding than they really are, so don't feel too bad if reading about them makes your head spin at first.

Assuming the rectangular looking box is "U5" it is a voltage regulator, part# LM78L05. The square boxes with the J-labels are the connections I mentioned above. I don't see any other rectangular looking boxes, so I hope that covers that.

The red lines are the traces on the physical circuit board.

This is the front of the BDE board. Do NOT, under any circumstance, try to copy this layout. It is wrong. But it shows you the general idea of how it's laid out:



Here is the back of the BDE board. The thick dark lines are the physical traces, which are the red lines in the other schematic you've found (I didn't look at your link, but I know what it is). Again, do NOT try to copy this, but hopefully it will give you an idea of how everything comes together:




As I said before, I swapped out the OPAMP he used since it was glaringly incorrect, but his product does not work. So a simple copying of the board above but using the correct OPAMP will not work. Some resistor values are slightly different since this is for a 1.6l car, but that's a total a 4 resistors out of them all. Otherwise, though, the circuit will be identical for your car...just NOT the one above (did I stress that enough? ha).