Cheap new coils for COP conversion, opinions?
 

I was bored and was doing some research for future mods, including COP conversion, and came across these on ebay: http://cgi.ebay.com/ebaymotors/ws/eB...m=160287926863

New replacement coils for ~$30 each plus shipping, with a 12 month warranty. What are mt.net's thoughts?

I much prefer paying $50-60 shipped for all four with connectors from a wrecker.

for example:

2000 Ignition Coil Toyota Corolla SET OF 4 $50 Honda & Toyota Menders USA-CO(Denver) E-mail 1-800-480-4544

Sound like a good deal if you can't get them from a junkyard with the connectors.

a lot of the yards advertise a set of 4, but the price is per each coil. I had to call 6 yards before one finally sold a full set at the price advertised.

Are these coil & ignitor in one?

Yes Steve. Look for a thread on COP. Many of us using those in this board.

Great :bigtu:

I want to use them on my 1.8 with LINK G3 ecu and run sequential ignition, I'll get on and find a set if they are good to go :D

Thanks for your help

Steve

i wish I could find a set of these. I've always managed to miss them by a hair.

Just found that an MR2 specialist here in the UK has some so just waiting for a price. Is there a thread or instructions about how to wire these for sequential using a standalone?

Cheers

Steve

Here: https://www.miataturbo.net/forum/sho...&highlight=COP

I'm not sure your Link ECU will be up to the task though.

I know for sure you can use them with MS and AEM standalones.

Yeah the Link G3 can do it no probs, it has 4 Ignition drivers, don't know why it never took off to well with the MX5/ Miatas's especially as they were half the price of Hydra / AEM etc, been superceeded by the G4 Storm now. In the UK the G3's been the choice of ECU for the MR2 guys the last couple of years loads of 600/700bhp cars using them, plenty with COP conversions so I know it'll work :)

Cheers for the instructions :bigtu:

Cool

Don't forget to change the dwell settings on the ECU!

And keep us posted.

Will do, read the whole COP thread earlier, that took some doing! The condensed version, basically has it all down, https://www.miataturbo.net/forum/showthread.php?t=12704 I'm hoping to get the connectors from the MR2 place and was going to replace the rest of the loom with a link loom, my looms been so chopped about now its probably better to start again. :)

What does it matter if the ecu supports full sequential ignition? The COPs work fine in wasted spark.

If you can run sequential why would you run wasted? Sequential they only have to fire half the amount.

What, you think you're going to wear them out or something?

If they spark half as much, 1/2 as much heat will be induced into the coils. So good for COP life. Also allows you to now run more dwell to get a little more energy into the spark that you could not have safely run in a wasted spark configuration. Doubles plug life too on regular cars, though this is insignificant on a turbo miata.

That's the thing. These aren't components that wear out very quickly. I've been running these plugs at 18 psi for a long time now. Years. They look like I just bought them.

As for the COP ignitors, if they were heat sensitive, being mounted on top of the head would probably be a bad place for them. I'd bet that the head supplies way more heat than the cycling of the coils.

Additionally, it seems unlikely that toyota would design an ignition system that would fail if constantly driven at high rpm in hot conditions. Except when you are above 3-4000 rpm, you aren't subjecting them to an unexpected load. And even if you exceed that, I strongly suspect that the margin of error is large for this part.

I'm not disagreeing with you. I answered your question. The coil and the igniter are two different things. The igniter is just a switch so to speak. It controls the coil. When you place a voltage on a coil it, produces an magnetic field in a direction perpendicular to the flow of current. At the exact instant that you apply the voltage to the coil, 100% of the energy is being converted into building a magnetic field, B, around the coil and none of the energy is converted into heat. The magnetic field around the coil grows at an exponential rate as it approaches saturation, B_max. When B=B_max, all the energy being put into the coil is being turned into heat. Current into the coil also increases exponentially. The resistivity of the coil increases as the temperature of the coil increases. As the temperature of the coil increases, the amount of current flowing through it decreases (more resistance, less current flow.. E=IR) and so does the resulting magnetic field B, and hence your spark is weaker.

If you hold dwell constant, then heat induced into the coil is a function of how many times you charge/discharge the coil. Sure, they're temperature changes with the surroundings, but the fact that HEAT induced is a function of charges/discharges remains.

Again, I'm not disagreeing with you. But I think you are bit confused on exactly how the coil works. Heat is not insignificant.

Yeah, I took physics, just like everyone else. I know that resistance rises as heat rises and that heat is produced by charging and discharging the coils. And I understand that spark strength is a function of the efficiency of this process.

I just suspect that Toyota took this into account when designing the system. I suspect that the internal circuits are robust enough that their performance doesn't degrade at temperatures that won't melt the body of the coil on plug unit. The reasons for such an overdesign should be pretty obvious. If ordinary duty heats up any of the electrically conductive parts significantly enough to degrade their performance, the added heat would further increase resistance in the circuit, which leads to further buildup of heat. This can quickly spiral into a failure of the circuit, maybe even a fire.

My hunch is that toyota designed the COP units to operate indefinitely at full performance during:
-100-150C underhood temperatures, which is reasonable to expect on many vehicles.
-8000 rpm sequential opereation, as on the celica motor.

Which means that running them in wasted spark isn't going to have any significant effect. I think if you ran them at 7000+ rpm for hours on wasted spark, you might get an equilibrium temperature within the plug somewhat higher than when you just putter around town, but realistically I don't think that temperature would ever be high enough to degrade performance. It isn't like the COP unit is thermally shielded from the engine bay and has a separate heat sink to dissipate heat- it shares a single thermal environment with the cylinder head. Both are going to be very hot when running.

And this doesn't even take into account that typical COP conversions are open to engine bay air circulation while OEM COP setups are typically hidden under a huge pile of plastic or metal shielding to keep the engine bay looking pretty.