Here's one for the late nighters to start chewing on.

While I'm in the process of testing my cylinder four misfire issues (checking wiring next), the thought of upgrades to the Subaru ignitor/coil on plug setup intrigued me. Thus the search for solutions that are adequate for what we do.

Yeah... theoretically you could get an ignitor and dual coil setup and run like the RS's do... but there are benefits to not running a wasted spark system... so why undo it.

Thus...

http://www.hksusa.com/products/?id=840


The Twin Power ignition amplifier incorporates both the CDI and transistor method ignition to provide optimum spark duration and maximum voltage output, resulting in crisper throttle response and a smoother engine powerband. The CDI method, capacity discharge ignition, provides maximum voltage by transferring all stored energy in the capacitor to the ignition coil so that the ignition current can buildup quickly, thus making the Twin Power very effective in the higher revs where a normal spark would tend to diminish. This strong rapid spark prevents the high rpm ignition miss that reduces peak power. The transistorized method generates high voltage by using transistors to cut off current to the coil, thus allowing for a long energy discharge. This longer spark duration allows the Twin Power to improve lower RPM throttle response and torque. The combination of the CDI and the transistor method incorporates two distinct systems into one high performance unit, hence the designation of Twin Power. The Twin Power produces a spark output that is typically 1.5-2.5 stronger than of the stock ignition system and consumes about 35% less power input than other ignition amplifiers. Each compact and attractive Twin power unit is constructed of durable anodized aluminum and sealed to prevent corrosion from moisture. General wiring harnesses are included in each unit to aid in installation and mounting. Vehicle Specific wiring harnesses are also available for certain models to further aid in installations that require intricate integration.

DLI II Types are vehicle application specific for Direct Ignition engines that utilize incorporated internal igniters and coils. (CARB E.O. # D-186-22)

http://www.hksusa.com/images_products/L_1267.jpg

Any thoughts? It would seem that we can take our ignitor trigger from the ECU and feed it into this, which in turn could fire the ignition system.

Just a thought.

Now.. I'm not sure what this does..... to be perfectly honest...

If I'm understanding this right... you trigger an ignitor, which triggers the primary windings on a coil, which dumps to a secondary winding (massive volts now) out to a wire to your plug.

Our system has the ignitor/coil integrated on the plug, so all the ECU does is trigger the ignitor and the process is completely contained right on your plug.

Thus the 3 wires going to our coil/ignitor combo. Pos/Neg/Trigger.

The 12 volt constant will keep the coil energized and the ECU just triggers it off via it's line in.

If that's the case.... what does the DLI do that is so impressive? It implies that it could

A: Use the ECU trigger to fire it's own ignitors to a coil, to the cylinder. Which would require coils and plug wires

B: Supplies the ignitor/coil with a steady voltage, and may fire the ignitor in the coil pack multiple times. Retaining our stock coil packs

C: hmmm it's midnight.. I can't really think of a C...

Can anyone shed some knowledge into this? I'm curious as to what can be done here. The coils on our plugs may be adequate... but they simply cannot supply the milijoules of voltage we should be needing by now with stage 4 setups.

Jorge (RiftsWRX)
www.ProjectWRX.com

I swear Jan Shim posted about this a month or two ago, IIRC we are still SOL as far as a ignition upgrade goes... Then again there is always a TEC

ah handy search funciton to the rescue

http://forums.i-club.com/forums/showthread.php?s=&threadid=229233&highlight=dli

Here's an ignition system to dream about - the Adrenaline Research Smartfire® (http://www.adrenalineresearch.com/). Not only does it produce a healthy spark, but it also tells you for each cylinder for each power cycle: the A/F ratio used, the torque produced, and whether there was a misfire or detonation. It's a little pricey, though. Maybe a group buy ...
:)

Base Price is $22,475

lol.

GDA

Good read on the twin power. I guess.. theoretically.. isn't it possible to source an external ignitor.

Theoretically... if individual ignitors could be sourced, then you could completely move to a wasted spark ignition, giving you all the options you'd ever need.

No different then an RS.. coil packs, plug wires, etc.

Just another thought... the trick is to find an ignitor for a DIS.

Jorge (RiftsWRX)
www.ProjectWRX.com

Originally posted by RiftsWRX
but there are benefits to not running a wasted spark system...Such as?

Well to begin with electrical efficiency. Kinda like how we do now, you can use a smaller coil since all the energy is going to the plug in question.

As opposed to a wasted spark which still will send a small amount of current to the cylinder on it's exhaust stroke. That still requires a coil sized to compensate for the loss, with more power involved to drive it as RPM increases. Which further results in an electrical system capable of handling 7000RPM worth of amperage.

People who would drag race and not want to run their alternator at all, and rely strickly on their battery power would have a different requirement then those with smaller, easier to energize, coils.

That's just one situation...

Don't get me wrong... if I was advocating against it, I wouldn't be trying to find ways of allowing myself to go back to it...

EDIT: then you have things like system simplicity, crossfire issues with plug wires, etc. etc. etc.

Jorge (RiftsWRX)
www.ProjectWRX.com

The TEC3 DFU coils draws 9 amps to give full spark energy to 15000 RPM. I dunno about you, but I wouldn't call that excessive current draw. There is no work being done on the spark plug fired in the exhaust stroke, so the waste spark current draw is very minimal.

I would be willing to bet that the stock ignition system is close to that current draw.

Originally posted by Austin
The TEC3 DFU coils draws 9 amps to give full spark energy to 15000 RPM. I dunno about you, but I wouldn't call that excessive current draw. There is no work being done on the spark plug fired in the exhaust stroke, so the waste spark current draw is very minimal.

I would be willing to bet that the stock ignition system is close to that current draw.

:lol:

Like I said.. that was ONE reason... which frankly, is not up for debate right now. Opinions vary....

ANYWAYS.... Like I was stating, if there was an external ignitor solution then you could technically go to ANY DIS setup available today.

Anyone have any suggestions for that?

Jorge (RiftsWRX)
www.ProjectWRX.com

Well for the moment, I don't think I'd be inclined to change the stock coil on plug system. My reasoning is as follows:

1) The Coil on plug (in theory anyway) is far superior to remote coil and ignition wire setups. No inductive losses, no wire break down issues, no cross fire issues, faster current rise times etc.

2) we don't know what we are changing from. --- has anyone found any reference that tells us what the energy delivery profile is for the stock coil on plug.

How much is the max energy it can deliver?

What if any changes occur in the energy delivery at high rpm ?

What's the spark duration?
what is the voltage rise time profile?

It's kind of hard to improve on an unknown.

I know Shiv likes to run a standard ignition system, but I suspect that has more to do with it gives him tuning flexibility that is difficult to achieve without the ability to control the ignition drivers in the ECU.



Multifire ignition systems only help on miss reduction at low rpm. Most of them cannot deliver more than one spark at higher engine speeds due to the time limitations to charge and discharge the systems. The same is true with long duration sparks they only help at low rpm. Since none of us are experiencing low rpm miss problems, I don't think there is any point to that.

The spark system will not use any more voltage than it needs to initiate the spark across the existing spark plug gap, so high voltage numbers do not always translate into usable improvement in ignition.

CDI ignition systems can produce very powerful sparks, but of very short duration. This gives impressive maximum energy delivery numbers for advertising purposes, but may not get the job done in the real world, as the very high energy spark can cause some odd problems.

In ignition wire systems it can make cross fire managment a nightmare, it can also cause plugs to fire outside the combustion chamber. If the spark voltage is high enough, it may be easier for the plug to discharge down the outside of the sparkplug insulator outside the combustion chamber than it is to initiate a spark through the high pressure mixture in the chamber.

Last I've seen comments that too high an energy spark can cause miss problems by "blowing a hole" through the mixture instead of igniting it, it simply pushes the gases out of the way when it creates the arc plazma, but does not last long enough to effect reliable ignition. Dr Jacobs the guy that invented the modern electronic ignition system was of this opinion. (by the way most manufactures liscense his patents).

He used to publish a very informative booklet on ignitions systems but I'm not sure if it is still available.

Larry

Hmm, the early WRX's with coil on plug (94-96?) have only two wires going to the plug, and external ignitors. Possibly you could run a DIS4 from MSD as this has enough leads for a 4cyl wasted spark system.

Oh and The TecIII ignition is really weak in my opinion if you compare it to many of the modern factory DIS systems, and ultra weak compared to say a DIS4-HO which honestly is overkill. A quick test to see if I had spark threw a huge number of sparks to every ground surface within 1' of the end of the wire. The TEC system seems to not arc unless there is less than 1" of gap.

The major advantage of the CDI is that it generally remains impervious to electrical shunts in the high voltage ignition circuit, especially those due to spark-plug contamination. For most applications, the spark duration of 0.1 - 0.3 ms is too brief to ensure that the air-fuel mixture will ignite reliably. CDI is only viable for specific types of engine. Transistorized ignition systems have virtually the same performance, but with a much longer spark duration.

As far as your test - while it might be fun to see how long an arc you can get with differenct ignition systems, it really doesn't tell you much about their performance.

It takes XX volts to arc through XX medium across a gap that is XX wide. Plain and simple electricity. It takes (in the neighborhood) about 400-450 volts to arc across the .026-.028" gap on your spark plug. Everything else is superfluous. Your DIS system might make 150,000 volts compared to the TEC's 70,000 volts, but those numbers have nothing do to with spark duration.

bump... ideas from anyone else?

Jorge (RiftsWRX)
www.ProjectWRX.com

From what I've read over time, the stock ignition system works very well and doesn't really need to be changed. On my Tec-II driven EJ25 it did idle a little smoother but that's with colder plugs regapped for the Tec.

As for the spark duration and power issue, don't forget your spark will behave differently when it's in a fuel/air mixture as it's got a far different ionization potential than open air.

-Michael