Aftermarket ignition ...do you really need one?

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pishta

pishta

I know I'm right....
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Saw this from Chrysler Engineer Dave Zelkowski, had this to say about aftermarket ignition systems-

"The ONLY thing they will do for you is lighten your wallet. If there is nothing wrong with the stock ignition components it won't help. If you have some old tired components then it could be a benefit. (This is a key phrase to take note of, 20 (50!) year old pieces will have lost some function) I've been through this aftermarket ignition thing before. I spent a week on the dyno with the Super Touring 2.0L testing five different systems whose manufacturer's claimed big results. I found zero. The down side to their systems were that the complexity was increased and they weighed more. The Dodge Super Touring Stratus uses a stock ignition system and a stock engine controller and makes 300hp normally aspirated."



Pishta

MSD 6 (deceased)
MSD 6 (deceased)
Mallory Hyfire V dinosaur (PN 690)
MARK TEN B
Crane Hi-6 (black)
Crane Hi-6 (black)

I never paid more than 10% of retail for any of these over 30 years of collecting. MARK TEN B has a toggle switch to enable/bypass and flipping the switch does zero to affect idle but it does alter the voltage sent to coil, hard to tell what it sends to coil but an analog meter kicked to >70V on the slow meter but an O-scope would tell me more, possibly 300V from the large capacitor in unit. All the multi strike units altered the idle just a tad but I think it was more of a retarding affect? This was on a 4 banger carbed truck with stock internals. The modern boxes DO add rev limiters and some add retard window features too so not a complete waste. Turbo and 13:1 motors may see benefits but not common builds.
 
I read in Smokey Yunichs book something along those same lines. As I recall, he was big on Amps.
While the CDI systems have an excellent response time, they don't make much for amps. Which is why they went to Multi-Striking. The thing is as rpm goes up, there is no longer time for multi-striking, so around 3000 rpm, they switch back to Single strike, which is now a low-amperage spark, allbeit hi-voltage if the matching coil is used.

After reading all that, I just slapped on the highest amperage coil I could find, with any decent trouble-free ECU, and the factory-type Distributor. It does the job, and in my case has been trouble-free since installation in the very early 2000s,
after my first CDI amplifier system failed.

The coil I selected is a big yellow square-top Accell SuperCoil, that runs the recommended Ballast Resistor, and is wired in the usual way. It seems to run pretty warm, but the temp doesn't seem to affect it, and it will go from very low idle to 7500 or more in the blink of an eye, so I was/am happy. It's pushing 24 years old now.
and when I pull the wire out of the cap during cranking,
it will set the grass on fire
in my neighbors yard.
lol.
 
Yea the testing on higher output ignition systems should be done on an engine with higher than normal cylinder pressures. Ever try to fire a plug in a 10:1 v8 with 30 pounds of boost and e85 AFRs in the 8s?
 
AJ/FormS said:
I read in Smokey Yunichs book something along those same lines. As I recall, he was big on Amps.
While the CDI systems have an excellent response time, they don't make much for amps. Which is why they went to Multi-Striking. The thing is as rpm goes up, there is no longer time for multi-striking, so around 3000 rpm, they switch back to Single strike, which is now a low-amperage spark, allbeit hi-voltage if the matching coil is used.

After reading all that, I just slapped on the highest amperage coil I could find, with any decent trouble-free ECU, and the factory-type Distributor. It does the job, and in my case has been trouble-free since installation in the very early 2000s,
after my first CDI amplifier system failed.

The coil I selected is a big yellow square-top Accell SuperCoil, that runs the recommended Ballast Resistor, and is wired in the usual way. It seems to run pretty warm, but the temp doesn't seem to affect it, and it will go from very low idle to 7500 or more in the blink of an eye, so I was/am happy. It's pushing 24 years old now.
and when I pull the wire out of the cap during cranking,
it will set the grass on fire
in my neighbors yard.
lol.
Click to expand...
Back in the day that yellow accel super coil was the one to have.
 
pishta said:
"The ONLY thing they will do for you is lighten your wallet
Click to expand...
I will agree, unless you have some wiss-bang high power engine as stated above.
Basic electronic ignition,set it and forget it for a normal streeter.
My last build I just left it with points. I only drive it occasionally anymore.
 
My take on Over-reving; not bashing Lelo;
IMO; on the street, with a typical SBM street-combo, over-reving should not be a thing
The reasons being;
With 3.55s and a 4-speed, my Barracuda can hit 85 mph @7200, in Second gear, which is well into "lose-your-license" territory, so it seldom goes there. 65 is 5500 still in Second, and that's about dead-on the power-peak. From there, it's a granny shift into Fourth, then, overdrive.
For the guy with an auto and 4.30 gears tho, that can somehow miss the 1-2 shift at 65=5500, I agree; protect your investment, lol. You know, in case the band blows up, or the servo rolls over. I mean that happens ......... right. I mean I've read about it.......

My secret weapon is having enough valvespring to keep the valve gear all together, and adjustable valve gear set to just a half-a turn preload.
But, I gotta admit; my cheap Autometer tach does have a rev limiter in it, which I set somewhere North of 7200. However, since I rebuilt my shifter in 2004, it has never even been tickled.
So far so good.
Ok so for the dual-purpose street machine, or a track-car; I get it.
In any case, I'm done with CDI's and especially with Multi-Strikes. Twice bitten, forever shy.
 
TT5.9mag said:
Yea the testing on higher output ignition systems should be done on an engine with higher than normal cylinder pressures. Ever try to fire a plug in a 10:1 v8 with 30 pounds of boost and e85 AFRs in the 8s?
Click to expand...
Not yet! :)
 
My setup is stock, 318/904/stock coil. modifications include Airgap, Holley 750 vacuum secondarys, Tti long tube headers, comp cam, Accel brass cap, Accel 8mil wires and Blue streak points. Going on 10 years without any issues.
 
[1] Phil Jacobs, founder of Jacobs ign systems says in his book: you do not want to trade current for voltage. That is because it is the heat in the current that ignites the mixture; the voltage is merely the enabler for the current to flow.

[2] CD [ capacitor discharge ] ign. The various 'box' igns. They work on a different principle to inductive igns, such as points, Chrys Elec, HEI etc.

[3] A CD spark has a very high energy output, about 150 mA. A Bosch 4 pin HEI module [ similar to GM HEI ] has a 60 mA spark. A single point dist starts off with 30mA at 1000 rpm....& drops to 5mA at 5000 rpm [ V8 engine ].

[4] A CD spark has much less duration than an inductive spark. That is why CD ign is often used with 2 stroke engines because the duration is so short that the spark does not have time to bleed off.

[5] My understanding is that when Autronics developed the MSD 6 ign, they were getting misfires at low rpms; this is because a long duration spark is needed at low rpm. So a bright spark [ pun intended ] said, 'We will make it multi spark'. Marketing trumps engineering failure!

[6] It is absurd to say as a blanket statement that an after market ign system won't help.
 
Warning, multi page long incoming post.

One line that I can't take credit for that sums up a lot: "If a match lights the fire just fine, a blowtorch isn't going to do any better." If the timing is optimal, and your current ignition lights off the mixture just fine every time, then you won't see any gain from something hotter.

But there are a couple situations where you can do better.

The "if the timing is optimal" is the first one. A stock distributor would have a good curve for a stock engine; if you have significant mods, you probably need to set the curve for what your engine needs. Sometimes aftermarket distributors or electronic controls make it easier to dial in the timing curve. The right curve can make a huge difference in drivability and economy as well as power. And crank fired ignitions (which will need to be paired with electronic controls for a street engine) can get the timing more accurate.

Related to timing; combustion chamber mods that get the mixture to burn faster will require less timing and make the engine more efficient. This is the deal with dual plug Hemi heads; the stock heads can get in a lot of air and fuel, but it takes longer to burn it than wedge heads. Two spark plugs with a significant distance between them will start two flame fronts and burn the mixture faster. The Gen III Hemis typically only need 20-22 degrees of timing at full throttle.

There are two cases where a stock Mopar distributor (points or electronic) may no longer deliver enough power. One is if you are making considerably more cylinder pressure; more compression or forced induction can increase the pressure to the point a stock ignition no longer generates enough voltage to jump the gap.

The other relates to dwell time. The longer you dwell a coil, the hotter the spark it generates until you hit either the coil's current limit or the ballast resistor doesn't allow any more current. And at high RPM, particularly with more cylinders, you the time to dwell the coil decreases and you get less spark energy.

There are several ways you can improve the ignition if you hit these problems. One is to upgrade the coil. I haven't seen what the larger Accel Super Stock coil (which appears to be discontinued) will do on a dyno, but I've seen their regular size coil lose 5 hp to a 30 year old Bosch stock coil. On a 100 hp four cylinder Porsche 944. It may well have been an upgrade from the stock 1960s era coils, but you can do better.

You can also get a bit of an improvement with more sophisticated dwell control. Points always use a fixed dwell angle, and stock Mopar ignition boxes leave the coil dwelled full time, interrupting it for a fixed time when it receives a pulse from the distributor sensor. A more sophisticated inductive ignition module (such as an HEI) can make better use of the available dwell time. Such ignitions also run cooler and eliminate the ballast resistor - they limit current by limiting dwell time.

Capacitive discharge ignitions get around dwell entirely. They use the coil as a transformer (so some of the coils designed for CDIs won't work with other ignition modules very well) and dump a high voltage pulse from a capacitor through it. So the limiting factor is how quickly the module can recharge the capacitor. They also generate a shorter spark with a faster voltage rise time. This can burn through fouling on spark plugs but can be a disadvantage at idle (which is why you see multispark ones). The faster rise time can also mean that you may need a degree or so less timing to have the flame front start a the same time as with a conventional ignition.

Or you can avoid having dwell fall off by running several coils, letting several dwell at the same time. You'll see this on virtually all automotive engines built after 2000 in the US, except for diesels of course and a few Hondas that held out with distributors for a few years past 2000. The Super Touring Dodges used this approach, and had a very good coil design that I've seen swapped onto other engines to get a hotter spark.
 
I always chuckled at multispark on a race engine that switches back to single at 3000 rpm. It will idle cleaner with that extra spark.
 
One of these ignitions that takes the current duties off the distributor points is a nice feature. Points will last forever and no worries of condenser failure and may eliminate ballast resistor too. So run any dizzy you want, I like that.

Of course the entire ignition box is your new failure point, and who carries a spare one of those around? Duraspark, cough cough.
I think every duraspark was installed on the side of the road with yellow barrel crimps.

Do you need it? No. But it sure looked good under the hood in 1990-something. Mine is behind the dash buzzing away like mad at idle. That part I could do without, but too late
 
Honestly nothing wrong with the Mopar ignition. Two biggies. Use the ecu for your rpm range, match the ballast resistor and the single most important thing is the dist. curve no matter what system you go with, and if running a chrome box on the street do not use the .25 ballast you will burn the box up fast. Thats designed for drag runs and needs to cool down. You can run them on the street with a ,8 though

ecu chart 2.png


ECUApplication.jpg


ecuII.jpg
 
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My 2 cents is the multi spark ignitions are mileage helpers down low and can help clean up the insides and reduce emissions.

After that, I have found the Chrysler ignitions to be just fine with an upgraded module. When the orange box was a quality unit, it was great for general performance and the chrome box for hot rods. I have a chrome box working 25 or so + years now.

MSD = constant failure.
 
MS Max.

Disagree with your blowtorch analogy. And so does every car maker. Because spark energy & spark plug gap size has increased over time since the days of the Model T.
When you light a blowtorch, you are lighting pure, unmixed gas. When you are igniting a mixture in a IC engine, the mix contains: air mixed with petrol [ the catalyst ] ...& residual exh gas. Exh gas does not burn very well...
Many cars have 0.060" or larger plug gaps. These bigger gaps load the ign system more, which can affect reliability. So there is a cost to make the system more reliable. Car makers do not spend this extra money unless there is a good reason for it......& they do not use big plug gaps unless there is a reason for it.
Many hotrodders do not understand that the rough idle they are getting after installing the big cam is the engine misfiring.........Anything that can increase the heat in the spark will help with the roughness & many people experience this improvement when they upgrade the ign system.
 
That saying is a first approximation: You can have an ignition that is powerful enough that the engine runs reasonably well, but leaves power on the table due to incomplete combustion. I've seen that happen on the dyno. But once you get a strong enough ignition to have complete combustion every time, adding even more power is only going to wear out your spark plugs.
 
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