As some of you know, I've been getting pretty crazy with my ignition system so I thought I would post some findings. For those unacquainted, I have been in the process of an extensive round of mods on my Buick including a 4t80e swap, and a twincharged setup with a monster supercharger and turbo. The scope of this thread will focus on my ignition system setup and findings though. I am currently running 3 ignition modules in parallel, water-cooled by my intercooler pump for durability, and they are driving 6 of the AEM branded IGN-1 ignition coils mounted on my valve covers with LS1 style spark plug wires for a nice short ignition lead/less chance of arcing.
As a disclaimer, I do NOT have any fancy test equipment or enough knowledge on the subject to give any real comparison numbers, just what I have been able to witness/test with my own two eyes and basic equipment/homemade test rigs so far. I am not out to convince anyone, you can either believe my finding or not, I don't want to debate it, I just want to put the information I've come to believe out there and let you decide for yourself. There are several questions I've had for a long time when it comes to ignition system performance, and I've been working on answering them for myself to the extent that I can right now in a static sense with the vehicle parked (not quite road ready yet, unfortunately), and I've made enough progress to be certain about a few things so I will post what I know so far.
Regarding the coils. You can't really improve upon the stock blue coils while utilizing the stock module and dwell. The ignition module limits max current through the coils, as well as dwell being locked in the PCM unless you mod it with tiny tuner or something (still on my to-test list). The stock coils are FAR from maxxed out in stock configuration. Two ignition modules in parallel appear to max out the coils at idle, I suspect at the lower dwell times in the upper RPMs that the coils might even benefit from 3 modules in parallel (which is what I have currently).
I have gone so far as to compare different input voltages up to 24V, as well as multiple modules and compared the stock coils to my IGN-1 coils. The stock coils provide higher voltage on a 12V input voltage, as evidenced by their ability to jump a larger gap than my IGN-1 coil. On a stock module setup, they put out similar enough spark energy that I could not tell a visible difference. However, the stock coils output leveled off at two modules, saw no improvement from three, whereas my IGN-1 coils continued to put off a thicker more consistent spark. My harness is only set up for 3 modules otherwise I would continue to add more to see where the IGN-1 stops improving.
The other thing worth mentioning is that increasing the input voltage to the stock coils resulted in a more consistent spark, but it did not appear to deliver any more total energy/a wider spark. I believe more input voltage primarily increases the spark voltage allowing it to more consistently jump a larger gap, and perhaps charging the coil faster at higher rpms, but does not deliver more spark energy, as the ignition module still limits current. I observed less amperage going through the power wire for the module at 24V than at 12V, though I don't recall what the exact numbers were. Note that I had the module powered independently of the ECU, so there would have been no dwell adjustment for the higher voltage, so I believe this is an accurate representation of internal current limitations in the ignition module itself.
So what does that mean in terms of how you should proceed with ignition system upgrades? Well it means that first and foremost the coils are not the bottleneck in your ignition system, the module is so that needs to be upgraded first. There are several ways to do this:
Higher input voltage such as from a kenne-belle boost-a-spark type system or other dc-dc boost converter will get you higher peak voltage, but not higher spark energy, resulting in a short duration, narrow spark. Basically, a stock-energy spark with more voltage potential to jump a gap. It may have some high RPM benefits due to faster coil charging (although possibly not since the module is still limiting current), but through a stock module, does not appear to deliver more energy.
CDI. I presume CDI would be a more extreme example of the same...much higher input voltage, much more voltage/gap jumping potential, but a very, very short duration weak spark. These would be your MSD boxes and most other ignition amplifiers. Expensive, not very reliable, can be highly effective in certain situations but are definitely a big trade-off.
Aftermarket standalone ignition. Expensive, complicated to install, great results, ideal scenario. To actually fix the limitations of the stock system would be the best way, but who wants to spend $1,000-2,000 on an electromotive xdi-2/trigger wheel/crank sensor/coils (which by the way uses our 3800 coils)...or the m&w setup, or whatever tickles your fancy. They are all expensive, they are all complicated, they all work great.
Lastly, and what I decided on for my car, is to simply apply the same concept we have for a long time to most other mods on the 3800 platform. Just take the stock parts and make them work better. Installing a second ignition module in parallel provides an INCREDIBLE increase in spark energy and voltage by doubling the current limitation on charging the coils. It's a considerably more significant difference than anything else I've tested, including running 24V to the coils, and using a capacitive discharge box (although granted, I have not tested that during this round of testing, but did so on a previous vehicle in similar testing years ago). This modification was the only one of those that makes you say, "holy shit" when you are doing a spark gap test and plug that second module in. Before this build, I tested the two module method on my car at up to .075" gap on methanol and 15+ lbs of boost with no apparent blowout. That was on stock coils (and I'm not even sure they were all blue coils). I am looking forward to really pushing the limits on my new setup once I get the car street ready, and I will certainly report back on any new findings.
Will two modules in parallel burn up coils? Will it burn up modules? The answer is yes and no. I burned up both during testing. I believe the coil failure was due to open circuiting the coils during these max output tests, and not anything that would occur during normal operation. I believe the module failure was due to the fact that I literally had the extra module hanging there bouncing around on things with no heatsink. Again, I do not think a normal installation with proper mounting and heatsink will have any issues. I ran for weeks as a daily driver without any problems, only burned up the coils during testing, and only burned up that module when I left the car idling for about a half hour one hot day, the thing was roasting hot. I should add that the primary module that was still installed on its heatsink bracket was fine and the car was still running. If it's something you are concerned about, just do like James and put the second module on a boost switch.
So in summary, there is pretty much nothing you can do in terms of coil upgrades or aftermarket ignition boxes while utilizing the stock ignition module that will have any significant effect. The answer is a second ignition module, period. It is cheap, and extremely effective. Make sure your spark plug wires are beefy and in good shape. If you find that the second module is still not enough, then and only then should you venture into the realm of upgraded coils and/or a third module or messing with the dwell in the computer.
The next big upgrade for my setup that I am investigating would be figuring out how to switch to sequential spark vs waste spark. With waste spark, my max dwell to maintain the 40% duty cycle limit on my IGN-1 coils would be 4ms at 6000 RPM...and the saturation dwell on them is supposedly 9ms, so I'm putting out less than half what they are capable of up top. In sequential spark with each coil firing only half as often as our waste-spark setup, I could ramp that up to at least 8ms and maintain that same 40% duty cycle and have some really serious spark power through the entire powerband. I haven't come up with a way to do that yet without going to a standalone ignition system, so it may not ever happen.
Also, I think it's probably pretty pointless to continue to upgrade my ignition system. My coils deliver a stupid hot spark right now and I have yet to even mess with dwell (which from looking at the stock table is pretty much maxxed out at idle in terms of ms, as well as at high rpm in terms of duty cycle, but has LOTS of room for improved spark from 2000-4500rpm), and if in doubt, I can still deliver up to 24V into my modules with my boost converter (however the coils are only rated for 18V, so I would not want to do that long-term). If I start having issues with burning up coils, I can certainly water cool those as well.
Anyway, I just felt like putting the info out there so hopefully people can actually get some performance out of their ignition systems vs just spending a lot of money for minimal gains. I would appreciate feedback from anyone else that tries it, particularly if you were having problems with blowout/breakup from a weak ignition system. As far as a how-to, just go to a junkyard, grab another module and pigtail, wire it in parallel to your harness, wire the outputs in parallel to your existing module, figure out how to mount/heatsink the thing and you're done. James has a prettier/more elegant mounting/wiring solution and there is a separate thread on it. Good luck, have fun.
As a disclaimer, I do NOT have any fancy test equipment or enough knowledge on the subject to give any real comparison numbers, just what I have been able to witness/test with my own two eyes and basic equipment/homemade test rigs so far. I am not out to convince anyone, you can either believe my finding or not, I don't want to debate it, I just want to put the information I've come to believe out there and let you decide for yourself. There are several questions I've had for a long time when it comes to ignition system performance, and I've been working on answering them for myself to the extent that I can right now in a static sense with the vehicle parked (not quite road ready yet, unfortunately), and I've made enough progress to be certain about a few things so I will post what I know so far.
Regarding the coils. You can't really improve upon the stock blue coils while utilizing the stock module and dwell. The ignition module limits max current through the coils, as well as dwell being locked in the PCM unless you mod it with tiny tuner or something (still on my to-test list). The stock coils are FAR from maxxed out in stock configuration. Two ignition modules in parallel appear to max out the coils at idle, I suspect at the lower dwell times in the upper RPMs that the coils might even benefit from 3 modules in parallel (which is what I have currently).
I have gone so far as to compare different input voltages up to 24V, as well as multiple modules and compared the stock coils to my IGN-1 coils. The stock coils provide higher voltage on a 12V input voltage, as evidenced by their ability to jump a larger gap than my IGN-1 coil. On a stock module setup, they put out similar enough spark energy that I could not tell a visible difference. However, the stock coils output leveled off at two modules, saw no improvement from three, whereas my IGN-1 coils continued to put off a thicker more consistent spark. My harness is only set up for 3 modules otherwise I would continue to add more to see where the IGN-1 stops improving.
The other thing worth mentioning is that increasing the input voltage to the stock coils resulted in a more consistent spark, but it did not appear to deliver any more total energy/a wider spark. I believe more input voltage primarily increases the spark voltage allowing it to more consistently jump a larger gap, and perhaps charging the coil faster at higher rpms, but does not deliver more spark energy, as the ignition module still limits current. I observed less amperage going through the power wire for the module at 24V than at 12V, though I don't recall what the exact numbers were. Note that I had the module powered independently of the ECU, so there would have been no dwell adjustment for the higher voltage, so I believe this is an accurate representation of internal current limitations in the ignition module itself.
So what does that mean in terms of how you should proceed with ignition system upgrades? Well it means that first and foremost the coils are not the bottleneck in your ignition system, the module is so that needs to be upgraded first. There are several ways to do this:
Higher input voltage such as from a kenne-belle boost-a-spark type system or other dc-dc boost converter will get you higher peak voltage, but not higher spark energy, resulting in a short duration, narrow spark. Basically, a stock-energy spark with more voltage potential to jump a gap. It may have some high RPM benefits due to faster coil charging (although possibly not since the module is still limiting current), but through a stock module, does not appear to deliver more energy.
CDI. I presume CDI would be a more extreme example of the same...much higher input voltage, much more voltage/gap jumping potential, but a very, very short duration weak spark. These would be your MSD boxes and most other ignition amplifiers. Expensive, not very reliable, can be highly effective in certain situations but are definitely a big trade-off.
Aftermarket standalone ignition. Expensive, complicated to install, great results, ideal scenario. To actually fix the limitations of the stock system would be the best way, but who wants to spend $1,000-2,000 on an electromotive xdi-2/trigger wheel/crank sensor/coils (which by the way uses our 3800 coils)...or the m&w setup, or whatever tickles your fancy. They are all expensive, they are all complicated, they all work great.
Lastly, and what I decided on for my car, is to simply apply the same concept we have for a long time to most other mods on the 3800 platform. Just take the stock parts and make them work better. Installing a second ignition module in parallel provides an INCREDIBLE increase in spark energy and voltage by doubling the current limitation on charging the coils. It's a considerably more significant difference than anything else I've tested, including running 24V to the coils, and using a capacitive discharge box (although granted, I have not tested that during this round of testing, but did so on a previous vehicle in similar testing years ago). This modification was the only one of those that makes you say, "holy shit" when you are doing a spark gap test and plug that second module in. Before this build, I tested the two module method on my car at up to .075" gap on methanol and 15+ lbs of boost with no apparent blowout. That was on stock coils (and I'm not even sure they were all blue coils). I am looking forward to really pushing the limits on my new setup once I get the car street ready, and I will certainly report back on any new findings.
Will two modules in parallel burn up coils? Will it burn up modules? The answer is yes and no. I burned up both during testing. I believe the coil failure was due to open circuiting the coils during these max output tests, and not anything that would occur during normal operation. I believe the module failure was due to the fact that I literally had the extra module hanging there bouncing around on things with no heatsink. Again, I do not think a normal installation with proper mounting and heatsink will have any issues. I ran for weeks as a daily driver without any problems, only burned up the coils during testing, and only burned up that module when I left the car idling for about a half hour one hot day, the thing was roasting hot. I should add that the primary module that was still installed on its heatsink bracket was fine and the car was still running. If it's something you are concerned about, just do like James and put the second module on a boost switch.
So in summary, there is pretty much nothing you can do in terms of coil upgrades or aftermarket ignition boxes while utilizing the stock ignition module that will have any significant effect. The answer is a second ignition module, period. It is cheap, and extremely effective. Make sure your spark plug wires are beefy and in good shape. If you find that the second module is still not enough, then and only then should you venture into the realm of upgraded coils and/or a third module or messing with the dwell in the computer.
The next big upgrade for my setup that I am investigating would be figuring out how to switch to sequential spark vs waste spark. With waste spark, my max dwell to maintain the 40% duty cycle limit on my IGN-1 coils would be 4ms at 6000 RPM...and the saturation dwell on them is supposedly 9ms, so I'm putting out less than half what they are capable of up top. In sequential spark with each coil firing only half as often as our waste-spark setup, I could ramp that up to at least 8ms and maintain that same 40% duty cycle and have some really serious spark power through the entire powerband. I haven't come up with a way to do that yet without going to a standalone ignition system, so it may not ever happen.
Also, I think it's probably pretty pointless to continue to upgrade my ignition system. My coils deliver a stupid hot spark right now and I have yet to even mess with dwell (which from looking at the stock table is pretty much maxxed out at idle in terms of ms, as well as at high rpm in terms of duty cycle, but has LOTS of room for improved spark from 2000-4500rpm), and if in doubt, I can still deliver up to 24V into my modules with my boost converter (however the coils are only rated for 18V, so I would not want to do that long-term). If I start having issues with burning up coils, I can certainly water cool those as well.
Anyway, I just felt like putting the info out there so hopefully people can actually get some performance out of their ignition systems vs just spending a lot of money for minimal gains. I would appreciate feedback from anyone else that tries it, particularly if you were having problems with blowout/breakup from a weak ignition system. As far as a how-to, just go to a junkyard, grab another module and pigtail, wire it in parallel to your harness, wire the outputs in parallel to your existing module, figure out how to mount/heatsink the thing and you're done. James has a prettier/more elegant mounting/wiring solution and there is a separate thread on it. Good luck, have fun.
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