you can drive with original coils till 100k mi, but is does not mean that they are operating as they should. A lot will deepens on your driving, the more you push your car- the quicker they will degrade.

I my self will make a Yukon coils upgrade kit, so i would not have to worry about ignition problems.

we Pettit guys relocate the coil pack off the engine.
I have ran oem coils for sometime and over the years i have ran other types. But I have never seen a white spot on the oem one since I did that relocation.
Now I dont have 30K on the car since i did the swap--but i do have 25K and most of that is on oem coils.
I have also lowered my redline down to 7.5 K, maybe the higher rpm's (to 9K) stress's the coils a little?
OD

I believe it does coz I zoom zoom more the first few months of ownership and that first set of coils didn't last too long

I had to call o'reilly today and I remember about the rx8's ignition coils. I called the onein norman, ok (405-573-0669) and they had some for $32 and a lifetime warranty. He said anytime they go out come by the store and we'll replace them.

I told him about how fast they go out on the rx8 and he said yeah no prob we'll replace them.

they're borg warden (BWD).

That is very good to know, thanks for checking that out.:beer05:

They are probably cheap coils that will burn out drastically faster than OEM. Not worth the hassle, if they suck.

connections could definately create some heat, but theres something deeper. i think what CRH is referring to is the heat produced by the coil itself.

coils are essentially transformers. but instead of step down from 120V to 15Vor whatever like for your laptop, its a step up transformer. if your familiar with the idea of how a transformer works, then you know that energy changes states, electrical, magnetic, and electrical again. its the efficiency of these changes that i think Ray is getting at.

remember no suich thing as free energy? thats because nothing is 100%efficient. apparently our coils are just less efficient than what easily doable by the industry

I got mine from Oreilley and they seem to be fine, but I probably won't keep my car long enough to see how long they last. I think it was about $140 shipped for all 4. Definitely idles at a lower rpm than before and a bit smoother too. If I knew I was going to keep my 8 a lot longer I probably would have ponied up for the BHR package.

well, theres 3 things main energy losses in a trafo, all create heat. i doubt hysterisis or winding have a big factor here, so i'm guessing the core is being saturated and we have ass loads of eddy current loss:eyetwitch

anyone who is keeping up here can listen to the frequency change, and apply some of the above to what you see here around the 1 minute mark:

http://www.youtube.com/watch?v=AhRx1XW0d2g

Wow, that's just enlightening as all hell. Normally I think of sparks in the combustion chamber as little discrete events but, really, it's almost constant arcing, isn't it? Plus, inside the engine, the whole deal is surrounded by intense fire... Holy crap! I have a new found respect for what designers of sparkplugs (even bad ones) have accomplished in terms of longevity. 30,000 miles at 40 mph average would take 750 hours. Imagine what that little test rig would look like after 750 hours of operation... Crazy.

lol.

Seriously?

Do you guys even understand how a coil works? You can't overheat the actual coil. Its just wire.
You can run the coil to 10 times the rate and power level that we use and still see no failure.
Its the ignitor (transistor) on TOP of the coil that has a thermal issue.

How many more times over the years does this need to be rehashed?
You more experienced forum members should be ashamed of yourselves.

^Um....

Wires have failure rates. They're surprisingly low, especially for copper.

Even a little bit of current... say 10 A (that's comparatively a LOT of current but for the sake of a power application like coils) will FRY most copper wires. 10A can produce a lot of heat which can and will MELT and destroy a lot of gauges lower than 20 gauge wiring.

I've already said my piece on this discussion back on page one, so I'm not going to argue the point of where a coil fails. I'd just like to refute your point because it's blatantly false.

for once, i can most certainly say yes :) and i have to say i'm embarressed at talking about eddy current which is primarily a no load energy loss. winding resistance is the real full load energy loss. must not have been sober. regardless, any energy loss here will be in the form of heat(refer to MM's post about the transistor thermal loading)

you wanna bet, i have a couple of bench supplies and free time lol :yesnod:
(i just poofed a couple small trafo's a few days back :) )

very likely true if you seperated components and ran it on a bench. though at the loads and duty the coils see in use, they are already inefficient thermally and/or have some poor packaging.


:tear:

:p:

You are missing the point.

The failure point is at the ignitor.
Its sensitivity to heat, current and duty cycle is greater by several orders of magnitude than the coil winding.
I've cut dozens of these things apart after failing. I've got dozens more if you would like to try yourself. The coil never fails. Its always the ignitor.

i think he was thinking within the limitations of our application mostly, and would be right. but hey, i poked at him to on that one :eyetwitch

for current capacity, remember AC and DC have many differences. i'm to out of it to try to think if your numbers are close.

I wasn't even talking about that. Transistors are very easy to pop with current. I have no doubt that you're probably right.

But you said that you can't overheat the actual coil because it's just "wire". That irked me because I know it's wrong. You probably just mean that the coil overheating will never be the actual problem with the OEM coils because the ignitor will always go first, which is probably statistically sound. But being the EE I am, I'll let you know there could be a time you have an ignitor that lasts and the wiring in the xfrmr loop that goes. Just possible.

That's all.

So you're right again; I was missing your point, but on purpose, haha.

..... i have coils sitting in the floor down the hall, but i'm lazy :P

iirc they are epoxy sealed or similar? odds of dissection and proper reassembly not good i'm sure

And I was thinking DC current but those are just rounded estimates. I can't remember the exact numbers for sure. BUT for AC amperage I can give you exact numbers because I have the code book right here... common house wires at 15 awg... or gauge 15 with three copper conductors... standard live, return, and ground wires can handle 25 Amps AC, just for comparative reference.

i love how people can be saying the same things, but have such different (and often in my case indirect) ways of going about it

:) i love it when magic smoke comes out to play(except the time i melted my breadboard too)

which reminds me, i need to get started on my laser harp project ;)

It can't happen. The ignitor will go WAY before you can overload the coils.
So -
It. Can't. Happen.

Stop thinking in a vacuum.

If you want to separate the coil section and show us how you can saturate and fry it, we will all applaud politely, commend you on your "ingenuity" (much in the same way we congratulate competitors in the Special Olympics) and then go on with our lives in the real world.

So - why do the ignitors overheat ?

Because they are in a hot place and they are being asked to fire twice as often as the coils in a piston motor, even though they are, essentially, light-weight duty coils for a 4-banger.

I got mine from O'Reilly. I worked there a couple years ago and have dealt with Borg Warner quite a bit while I worked there. They (Borg Warner) seem like a pretty good stock replacement. Even if they only like 10K miles it takes 25 minutes to swap them out. I bought mine for about $135 in Edmond, Ok. If I do have any problems I'll just swap them out at the O'Reilly's in Stillwater. They overnight ship to all their stores everyday, unlike Autozone (also worked there).

I was talking with the service manager at Mazda Saturday regarding my car potentially needing a new engine and he informed me that misfires are acceptable on the Renesis, as long as the number is low, ~10-15 per drive cycle... Thought that was interesting.

Some Ignition Coils also have OIL Inside (Oil Filled) for Cooling..

Ours do not.
Wouldn't matter - the coil isn't the problem.