Mercedes coil is perfect but needs 2 Ohm resistor.

[DreamV4]

I found bunch of Toyota and 2 Mercedes ign coils at home.
OEM specs 2.7 Ohm, Mercedes 0.7 Ohm primary.

 

[02GF74]

If it needs 2 ohm resistor then it isn't perfect.

75% of the available power is being wasted in the resistor, so the spark may end up being weaker, which also depends on how long the ecu supplies power to the coil.

It may work but don't be surprised if it doesn't. (COPs are the way forward).

 

[DreamV4]

If it needs 2 ohm resistor then it isn't perfect.

75% of the available power is being wasted in the resistor, so the spark may end up being weaker, which also depends on how long the ecu supplies power to the coil.

It may work but don't be surprised if it doesn't. (COPs are the way forward).

which ones? part #? do they have same resistance?

 

[Radioguylogs]

...75% of the available power is being wasted in the resistor,...

I'm not sure 75% of the power would be wasted in the resistor. This discussion is neglecting the total impedance , including the reactance (inductance) of the windings in the coils.

Regardless, we want the current in the coil primary windings to build to a certain level, then cause the magnetic field in the windings to collapse instantly to produce the spark energy. The spark energy comes form the collapse of the field, not directly from the primary current.

If the current builds to the desired level with resistor in place, then life is good.

BTW, the value of the condenser has an effect on the generation of the spark with a given coil.

 

[DreamV4]

many Ford coils have 2 pins, Toyota has 4(cannot be used for bikes, I think).
I'll get coils from Ford Expedition. BTW, they are $30 shipped from ebay for 8 coils.

 

[MaxMidnight]

For the cost of a 2ohm resistor it would be worth a punt.

 

[02GF74]

Yes you are correct, I wanted to keep it simple; how much current builds up in the coil depends on how for long the ignition unit is turned on.

 

[Traumahawk]

many Ford coils have 2 pins, Toyota has 4(cannot be used for bikes, I think).
I'll get coils from Ford Expedition. BTW, they are $30 shipped from ebay for 8 coils.

BTW there is a previous member on here that FRIED his stock ECU trying to run Ford COPS with his stock set up. He had to swap to an ignitech after that. Things still needed to be swapped around to make the Ignitech work with the ford COPS.