Ignition Break Up at 7400 RPM - AEM IGN-1A Coils
 

Here's the current setup:

SakeBombGarage AEM Coil setup, with the corrected Dwell settings
(I'm the lucky guy that discovered the dwell settings were backwards in the SG documentation)

Spark Plugs are heat range 9.
Single Turbo T04S, nothing extravagant
Resonated Mid-Pipe (Vibrant Resonator)
Racing Beat Dual Catback.

This is an autox car, and is setup to run to 8900 RPM, which I have done several times in the past.

Lately I have noticed that it feels like the ignition is breaking up.

It was only recently I was at a course where I could have revved the engine higher, but it didn't seem to want to.

So I got a trip permit (no tags in a few years now), took it out on the road and tested it.

Once it gets to about 7400 RPM it starts to misfire, causing it to shake so badly that I have to get out of the throttle.

What I suspect: That that AEM IGN-1A coils just are not providing enough spark at the high RPM range.

There has been quite a bit of speculation about waste spark problems with this coil due to the duty cycle required of them at high RPMs

I have asked about the waste spark in other threads, without any real answers.

Any useful thoughts on this?

Other things to consider for the ignition break up?
(Fuel pressure appears to be OK, checked that)

Or should I put back the stock setup with the HKS Twin Power?
Which is what I am thinking of doing anyway.

I had always thought the mid-pipe was robbing power - it's just there for SCCA noise limits.

So I put the straight midpipe in, changed the plugs and took it for a drive.
BTW, the plugs looked fine.

There was some improvement, the car pulls hard to 7.5 k or so, and I could get to nearly 8k RPM, but then it just falls on it's face.

The last track day I did the FD was capable of pulling 7800 RPM in 4th gear down the long front straight at PIR with no problem, so this just isn't right.

The car doesn't spend a lot of time above 8k, that is just to avoid shifting from 2nd to 3rd on fast autocross courses.

One big important thing I've learned with some customers is that the grounding of these coils has to be SUPERB. Check over that and contact Ludwig for his spreadsheet if using the PFC...

Grounding is directly to the top of the motor as close as I could get it, contact area well cleaned first.

Negative lead is to the circuit breaker right next to the battery.

The car pulls really hard to 7k or so, tapers off and won't go past 7900 or so. Probably should put the laptop in the car and log it to get accurate numbers, but it is so far off from what it should be doing.

The AEM coils seemed a good idea, but I should have thought it through better.

With a 4 channel ECU they probably work great, but for my application with the PFC I think not so much.

I do have Ludwig's spreadsheet. At 8k the the AEM coils are at 93% duty cycle, and they won't live long there. With the initial incorrect SG dwell settings both leading coils fried at idle with 83% duty cycle.

What are the AFR's at that RPM range? Whats your timing?

I had terrbile breakup w/ water inj and stock coils/twin power on T04R at 500+hp levels. It turned out that the wideband was showing leaner then the true AFR due to an exhaust leak at the downpipe. Car was dipping into my guess, the very low 10's with water/inj. I leaned the mixture out to an accurate low 11's and the car pulls like a beast, super clean power. It could simply be too much fuel.

Also, the BUR9EQP are garbage. I don't care what anyone on this forum says. Pick-up some NGK R6725. My idle is way cleaner, throttle reponse, etc then the factory plugs.

Haven't checked the AFRs - the connection to the DataLogit is not working properly.
The AFR gauges is working, but logging is not. I could eyeball it and at least get an idea if they are still in the ballpark.

Interesting point about the exhaust leak. I've pretty much given up on getting a complete seal with the VBand clamp on the turbo flange, and so will keep that in mind.

Actually I was not using the stock plugs.

I just pulled the NGK BR9EIX Iridium plugs, and they looked really good., much better than the BUR9EQP ever looked. The stock plugs always looked fouled, while the Iridium plugs looked great, nice even tan color and no fouling.

Currently I have in Autolite Racing Plugs, AR3932X. I will run those for a bit and see how they compare to the NGK Iridium plugs.

I have these coils, as we discussed.

on a Precision 6266.
Wastespark.
and 10gph of 50/50 water methanol

I dont have any issues running to 8100rpm.

The PFC only makes ignition timing and fuel correction changes to 8,000 rpms. Past that, it is still basing its adjustments off of the last (8,000rpm) cell. 8,900 is a stretch for the resolution available in the PFC.

Also make sure that your battery and your alternator are in proper working order.

-J

Also, Fd's commonly have grounding issues in the gauge cluster which cause the tachometer to read incorrectly. I would log a run with the PFC or watch the rpms on the hand held display in order to make sure that you are actually having the issue where you THINK you are.

-J

The PFC has easily run up to 9k before now.

I didn't didn't expect more power, it was just to avoid shifting.

Good point, I can check that.

Grab your cell phone, turn on the vid camera and record your dash as you do a pull. Go back and watch your afr gauge through the run.

I put a GoPro in the car and made a run.
The resolution of the GoPro is so bad that the gauge needle can't really be seen.

But, I did watch the gauge - it dipped down to 8!

OK, that is way too much fuel. The last person to tune it seems to have been overly cautious.

If anyone *really* wants to see the gauge, I can use a different camera, but I don't think that necessary at this point.

I did log with FC-Edit during the run.
Then loaded the logging text file into Excel an charted RPM.

Highest RPM is 7961, corresponding with what I saw on the tach.

Some background: In case you're wondering why I seemed to be ready to blame the coils, the SG coil setup caused me a fair bit of grief last year due to the incorrect installation instructions.

It took some time to convince the folks at SG that their installation docs were wrong, and that the leading coils had fried at idle. All of which left me without a car to drive during an out-of-town race weekend.

So the coils came high on my list of things to look for with this.

So it looks like some tuning is in order to correct the overly rich condition.

Seem reasonable?

Sounds reasonable.

-J

Some days stock class sounds really attractive.

Those doubts all disappear every time I get to drive the FD. :nod:

If pins B, C, and D are all grounded to the top of the engine, that would be a good place to start.

I did the first install of these coils with a PFC almost 8 years ago. That first car, and many since, have not had any issues and have performed very well when wired properly. That first car ran perfectly to 22 psi, and STILL does all these years later. When short cuts are taken, there can easily be spark blow out issues.

Unless you drive the car all day long at 9000 rpm, the duty cycle isn't an issue. You boiled coils with SBG's ass backward settings because they produced high dwell at idle.

If you need help, let me know.

There haven't been any shortcuts.

Yeah, I figured that out last August.

Thanks, will do, but at this time it appears to be a tuning issue.

You're the one that made it easy for the rest of us with the coils. As I stated, I used your spreadsheet for my one racecar and a couple customers and have NEVER had an issue coupled with proper wiring (ie proper ground points as labeled).

I should be running close to 28psi on a relatively large turbo in June sometime. Water injection, pulls to 9500rpm, and some good driveline modifications should make for a fun time. From what I've experienced with thus far I don't see there being a problem with the ignition system.

Hmmm I have a set of these as well. I haven't gone beyond starting and idling the car (good thing apparently). Do you mind sharing with us the proper settings so I can make sure I'm not running everything backwards?

Do you not log the wideband with the datalogit?

No, it is not currently working.

I'd get that fixed asap before trying to diagnose with a gauge. Many times the displays are filtered and 'padded' to the point of being useless for transient issues. Poring over the raw data will make your life much easier.

-David Guy
MEP

You said you where seeing an AF of 8? No wonder your car falls on it's face ;) Anything bellow 9.5 and the engine will start to strugle.

Id get a new tune on it. I did a street tune on my BP rew engine and as soon as i hit boost in the beginning it was showing 9.2 and so on, it would just sputter. So take off some fuel and have a look.

Our most likely running way too rich.

JT

They sent out a mass email to all the customers with them.

The proper settings they intend to pass out are:

IGL

10000rpm 150
8000rpm 144
4000rpm 108
2000rpm 48
1000rpm 24
480rpm 12


IGT

10000rpm 240
8000rpm 192
4000rpm 96
2000rpm 48
1000rpm 24
480rpm 12

These arent the settings I use, but they are the starting point SakeBombGarage recommends.

The SBG harness separates battery and engine ground. Engine ground to chassis obviously needs to be good but that doesn't seem to be an issue for him.

If anyone has questions about their install or issues please do not hesitate to contact us: info@sakebombgarage.com

Unfortunately when we were originally putting together the instruction manual for our ignition kit, we accidentally reversed our dwell curve values when we were mocking up some screen shots to step everyone through the process of setting up with the Datalogit. We printed a handful of these incorrect instruction booklets before becoming aware of the error, and corrected the dwell settings screenshot before the ignition kit went into full production.

We have individually contacted every ignition kit customer who could have possibly received one of these incorrect booklets and updated the error. For those customers who requested, we gladly replaced their AEM Smart Coils with brand new units just to be sure. We sincerely regret the error, but have done everything in our power to remedy the situation with our customers and we feel we have done that. Again, if anyone has any concerns about their SBG ignition kit, please do not hesitate to contact us!

As for jkstill, it sounds like you're choking on fuel up top. When did this issue start and what was your setup before the coil addition? Same tune? Our dwell curve is conservative and can be increased if needed but I would wager with the information provided so far that it's a fueling issue.