TeamRX8

iTrader: (25)

Thought this might be better off as it's own thread. Somebody asked about coils for FI use on the RX-8 that work at the OE dwell settings.

Your numbers are off compared to other data I have.

Maybe you can explain why they don't misfire at a 3mS dwell setting until boost is higher than anything you will ever see on a Renesis engine ...

olddragger

iTrader: (3)

thanks Mark--this may be exactly what I have been looking for. I will study this , this w/e.
I havent had a chance to look at the pin out etc--but what connector does this coil use?

TeamRX8

iTrader: (25)

It uses a 5-pin, in addition to the three OE wires there is a common secondary groynd like the GM coil. The 5th pin is for a common switched 12V power wire. This is where it differs from the OE and GM coils.

MazdaManiac

iTrader: (3)

Interesting assertion.

I don't get misfires on the BHR system at 10 PSI on a 35r with stock dwell.

I guess it depends on timing, AFR and other stuff.

My main issue at this point is that, even if they could ignite water, they still draw too much current for the OE harness when the dwell is set to anything that makes them any more powerful than what we use, meaning there would have to be additional wiring to make them work.

Not that this can't be addressed (my original system had an external power harness that we deleted from the BHR system because it wasn't necessary and complicated the otherwise P-n-P nature of the kit).

TeamRX8

iTrader: (25)

It's an open forum. Anyone is free to post.

AEM has these rebranded with their name, but it is the same coil. Their price is higher or at least I have never seen them priced lower in public.

We are talking about using them at 3 ms, not 6.5ms as in your example. The output is just one spec. It is not the end all reason to say yea or nea.


.

MazdaManiac

iTrader: (3)

Oh? Then what is? Color?

olddragger

iTrader: (3)

maybe cost and the ability for us boosted guys to use them with the oem dwell settings?
Those are big selling points for me.
base dwell for this coil is 3ms.

Mark thanks for the pin info.

In reading it seems that some rx7 folks have been using these for "awhile"?
I do believe they where using mostly the dumb kind.
NP's that I can find?
I tried calling AEM tech today--but the famous busy signal was omnipresent.

MazdaManiac

iTrader: (3)

There is no such thing as "base dwell".
There is only minimum and maximum dwell.
These coils at minimum dwell produce less output current then the Yukon-style coils at the same dwell. Same is true at 3.5ms (OE Renesis dwell).
They don't start to shine until 5ms and are really kicking *** at 7ms.
They have a maximum dwell of 9ms or so before they tip over.
The Yukon-style coils saturate way before that and are cut off automatically by the ignitor (as opposed to overheating like the stock coils).
Since you only have 6.6ms between combustion events on a rotary motor at 9000 RPM, you are limited in how long you can dwell the coil (about 5.5ms).
At 5.5ms, their output is identical to the Yukon-style coils.

TeamRX8

iTrader: (25)

Nevermind that they have been successfully used on 2 bar rotary FI engines @ 3 ms without issue

They simply don't need to be run at those high dwell settings and are more consistent and reliable as a result. Most have used them in the 2.5 - 4.0 ms range on very high output FI engines for years.

A standard GM HEI sparkplug wire connector is another positive

I still say your comparison numbers are way off.

olddragger

iTrader: (3)

good info Team. I too, in reading have found where some folks have been using these coils on high output engines for some time. So far I have not found a downside?

On the base dwell thing? I was just repeating what was listed in the tech section describing the coil.

TeamRX8

iTrader: (25)

Another point is that the wiring may only be 18 Ga. but the power signal is also only 5 volts. It potentially can handle more amps than was suggested earlier. Of course other factors and conditions can apply as always. At 3ms they will pull 4.5A which should not be a problem.

MazdaManiac

iTrader: (3)

That is incorrect.
The power signal is 12v.
The trigger is 3v.

TeamRX8

iTrader: (25)

Since I was using the amp specs for 12V service it's a minor, but worth noting detail. I did mean to say "trigger" rather than "power"

Mazurfer

I have no business in this thread other than to learn and say this is somewhat refreshing!
Swear I thought a group hug was gonna break out!



Then, I caught up on the Raceroots, Scotts, and sadly the BHR thread(where went off on unwarranted tangent and all hell broke loose) after my install yesterday.

That is all............I shall retreat to the shadows.

8upbad

iTrader: (3)

Does this mean he's not the unknown auto-xr any more?

olddragger

iTrader: (3)

one thing stands out about this coils. They have a longer spark duration than others.
hmmmmmmm.

Mazurfer

It has shown up in various threads from time to time....................don't worry, that bag is a permanent fixture.

MazdaManiac

iTrader: (3)

First of all, no they don't.
At nominal dwell, the duration on the A1 is actually shorter than the Yukon-type coils (about .5ms).
Second, long spark duration simply means that the current delivered is done so over a longer period of time which means, effectively that you have ceded some control over flame front to a longer ignition kernal. Which is, essentially, bad.

In short, you want all of the current right up front in the smallest possible kernal evolution time before propagation.

MazdaManiac

iTrader: (3)

The best comparison is going to be on the bench.

At some point, if it seems worthwhile, I'll put them side-by-side.

olddragger

iTrader: (3)

the ign A1 coil list a arc duration of 3.2 ms with a 3ms of dwell
the ls2 ignition coil lists the arc duration of 2 ms at 5 ms dwell
posting as stated on their each perspective specification sheets


millijoles and milliamps topic could make for a very long thread--rather not?

MazdaManiac

iTrader: (3)

That is incorrect (not that it matters because you didn't reference nominal voltage).
AT 3.5ms, the A1 has a spark duration of just over a millisecond.


Also incorrect.

olddragger

iTrader: (3)

this is copied from the mega squirt journal:

"The dwell should be set at 5 milliseconds input pulse trigger - going longer
does not generate any more spark current.
Dwell 5.5 milliseconds
Maximum Spark Duration2.0 milliseconds"

olddragger

iTrader: (3)

you know Ray, it may be worthwhile pursuing for your company to take a close look at this coil and if it meets ya'lls high standards maybe you could offer a kit for the FI crowd that do not want to change their dwell times?
After researching a little it seems that these coils have been around a while and have a good reputation?
The only benefit that I can see is the longer duration of the spark and the lower required dwell time?
I dont think they will burn up wires/sparkplugs any faster than the truck or ls2 coils if you keep the dwell and charge voltage reasonable?
The increased energy may make the 13b msp fi engine more friendly toward the barless plug?
Things are always changing and these may warrant a close look?

TeamRX8

iTrader: (25)

Since your boy is in here saying the Yukon coil trumps it in every regard I'm not sure what your point is or why you are questioning this coil rather than the one BHR uses

MazdaManiac

iTrader: (3)

And you wonder why I "pick" on you.
What did we just say about spark duration?
What did we just say about native dwell?
You "don't think" what about plugs and wires? What is this thinking based on?
The Renesis is not "friendly" to barless plugs? Are you serious?

The AEM coil is excellent. It is a nice looking package and its output and service specs are attractive.
But you have confused it with the fantasy product in your mind - a product that has the primary criteria of simply NOT being what is already available.