Steve, thanks for doing the legwork on this. Great find from manufacturer. This seems to match Ed's comments.
Anybody want to go 123 ignition? (Possible group buy)
- Thread starter Nicad
- Start date
jmackro
Well-Known Member
Stevehose said:
Thanks - that does help. Ed's website, 123ignitionusa.com is confusing on the choice of coil. Both red and blue Bosch coils are offered for sale on the site, yet neither the 123 manual nor anything else on the site says much about coil choice.
I think the ballast resistor does a couple of things:
1 - The resistor protects the coil from overheating and points from oxidizing due to too much current. The condensor also protects the points by absorbing the inductive "kick back" when the coil is switched off.
2 - The resistor allows the coil to receive a similar voltages during "start" and "run" conditions. System voltage is reduced when the starter is operating, so by bypassing the resistor while starting, the coil can receive the same voltage it receives through the resistor when the engine is running. For that to work, you need a coil that provides sufficient output voltage when its input is only ~ 9V. I found a more detailed discussion at: http://www.burtonpower.com/tuning-guides/tuning-guide-pages/ignition-systems.html
Well, this is getting frustrating. After reading Jay's notes above, I did a bit of interweb research. I can tell you that I don't think I found anything "definitive". But I did read a lot of comments that were in line with the ballast resistor use in conjunction with reduced voltage at start-up. That would support the info Jay sent. However, I also found a lot of info relative to specs only relating to a points style system. Electronic systems are a completely different animal, and one should follow the manufacturer's requirements. This would support the info Steve and I heard from 123.
I have a red coil on the way, and more than a few weeks before I will be monkeying around with this. Hopefully we'll learn more by then. Either way, I am thrilled to be upgrading the ignition system on my coupe.
I have a red coil on the way, and more than a few weeks before I will be monkeying around with this. Hopefully we'll learn more by then. Either way, I am thrilled to be upgrading the ignition system on my coupe.
Here's the wiring diagram from 123ignition. No ballast resister shown.
jmackro
Well-Known Member
I too did some more noodling around on the 123ignitionusa site and found something in the Frequently Asked Questions section that matches what Stevehose got from the Benz Forum:
What kind of coil do you recommend?
For 4 cylinder engines you could use the original coil or other coils with a primary resistance of at least 1.0 Ohm. For standard street engines we advise a "Bosch Blue" or "Beru ZS106" coil. For high rpm engines a "Bosch red (0 221 119 030)" or "Beru ZS109" is much better.
For 6 cylinder engines we advise to change your coil to a high performance coil because of the short load time in the higher rpm range. Make sure you use coils with a primary resistance of at least 1.0 Ohm. ( 1,0 Ohm or more ) For standard street engines we advise a "Bosch Blue" or "Beru ZS106" coil. For high rpm engines a "Bosch red (0 221 119 030)" or "Beru ZS109" is much better.
source: http://123ignition.nl/page.phtml?id=19#
What kind of coil do you recommend?
For 4 cylinder engines you could use the original coil or other coils with a primary resistance of at least 1.0 Ohm. For standard street engines we advise a "Bosch Blue" or "Beru ZS106" coil. For high rpm engines a "Bosch red (0 221 119 030)" or "Beru ZS109" is much better.
For 6 cylinder engines we advise to change your coil to a high performance coil because of the short load time in the higher rpm range. Make sure you use coils with a primary resistance of at least 1.0 Ohm. ( 1,0 Ohm or more ) For standard street engines we advise a "Bosch Blue" or "Beru ZS106" coil. For high rpm engines a "Bosch red (0 221 119 030)" or "Beru ZS109" is much better.
source: http://123ignition.nl/page.phtml?id=19#
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Tonight I added a male connector to the input side of the ballast resistor and switched the output wire to this. This will bypass the resistor and I will see how it goes. I have a spare red coil that I will pack away in the car so if the current one blows up I can swap in the new coil, put the wire back in its original spot, and carry on. It's raining all weekend so a field report will come later.
Hi Al. YES. I initiated a group buy with Ed at 123 ignition this week. I know at least one unit is purchased (mine) so far. The first 4 get a 5% discount. If a 5th is purchased, it goes to 10% (first 4 get a refund). The coupon code is farther up this string - 914 something... Please feel free to buy now so I get 5 more percent off.
Al/all, sorry for being vague last night. I was sitting in a movie theater with my wife and she was (rightfully) giving me the evil eye for posting during our date. 
The active 5% / 10% code is:
914world5
All one word, lower case. It is active until April 20. Hoping several of us can save 10%
The active 5% / 10% code is:
914world5
All one word, lower case. It is active until April 20. Hoping several of us can save 10%
Hello all. I just learned that my unit shipped out today (dizzy, coil, and usb cable). I have the wires coming directly from Kingsborne, which also shipped today. Ed contacted me and apologized that he had two email conversations going at the same time. Our group buy code should be:
e9groupbuy
All lower case, one word.
Evidently I am the only one this time around (so far). But Ed is tracking this in hope if getting the larger discount.
I still have to determine if I will use or bypass the ballast resistor...
e9groupbuy
All lower case, one word.
Evidently I am the only one this time around (so far). But Ed is tracking this in hope if getting the larger discount.
I still have to determine if I will use or bypass the ballast resistor...
I drove with the ballast resistor bypassed over the weekend. Amps from the coil went from 2.8 to 3.6. Not sure i noticed a difference driveability-wise but it runs great especially in higher rpms. I've packed the spare coil in the trunk and will report any long term issues. So far so good but a long road trip will be the deciding factor.
jmackro
Well-Known Member
Ooh, data!
Ohm's law tells us that R = V/i. So the coil alone must have resistance of 12 v / 3.6 a = 3.3 Ω. The coil + ballast resistor must have a combined resistance of 12 v / 2.8 a = 4.3 Ω. Therefore, the ballast resistor alone would have resistance of 4.3 Ω - 3.3 Ω = 1.0 Ω
Since power = volts x amps, the coil is dissipating 43.2 watts (12 v x 3.6 a) without the ballast resistor. The power dissipation in the circuit with the ballast resistor and coil in series would total 33.6 watts (12 v x 2.8 a). That 33.6 watts would be distributed as 7.8 w in the resistor and 25.8 w in the coil (power = amps squared x resistance, or 2.8 a x 2.8 a x 3.3 Ω = 25.8 w in the coil).
Therefore, without the ballast resistor, the coil is dissipating 43.2 / 25.8 = 1.67 times as much power as it does with the resistor. Admittedly, this assumes the coil is a purely resistive load, while in fact it has a lot of inductance. But that 1.67 x ratio should be close.
Is dissipating 2/3rds more power in the coil a problem? Well, Stevehose long road trip will tell!
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I am curious how much the impedance is potentially skewing these resistance based formulas. I only say that because these numbers do not necessarily match the Bosch coil resistances (that I've read people having measured in other forum posts - specifically MB and 2002). But the math and principles are solid!!! Thank you for posting.
jmackro
Well-Known Member
Yes, I agree; for example, I thought ballast resistors were more like 1.8 Ω, than 1.0 Ω. One question is whether Stevehose took the current measurements with the engine off (so the coil was a purely resistive load) or with it running (causing its inductance to increase the total impedance).
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1.8 ohm resistor measurements taken engine running with the 123 software. Also the voltage is more like 12.8 at idle would that change things or is that just a constant?
jmackro
Well-Known Member
Greater voltage across the coil means more power dissipated in the coil. So the wattage numbers go up, but I still get a 1-2/3 increase in power between the ballast resistor and no resistor scenarios.
Admittedly my numbers aren't 100% accurate, as the resistor should be 1.8 Ω, not 1.0 Ω. Again, the fact that the coil is an inductor probably explains this.
Hi Jay. I agree that there is a dynamic factor within the induction component that adds some variability with the formula. But I suspect the general increase is about what you are coming up with at 1.67 increase. It is great to see these formulaic calculations applied to our ignition system.
Happy day today - the 123 ignition arrived. Quicker than I expected, and I am impressed with the machined quality of the metal body. I didn't realize how beautiful this piece would be.
By the way, I found another comment from Petronix (I realize this is different, but perhaps similar) that they recommend omitting the ballast resistor similar to what 123ignitions said. If we take this as fact, it would seem the breakerless ignition company's systems can handle the increased load without incident - likely due to the lack of points and condenser. But that doesn't address any concern of overloading our coils. Maybe this is less of a concern than we think? The coils seem to be listed as 12V coils. Does that mean they can handle the 14+ volts they will see while driving? I don't know. I re-read Mr. Siegel's book last night as well as a post from him and others and I just don't know how globally the recommendation to omit the ballast resistor can be taken.