Blue coil Bosch

[40cpe]

A point about using a ballast resistor vs a constant resistance coil on a points system: A ballast resistor has lower resistance when cold and higher resistance when hot, which is the principle behind its design to provide a higher voltage for starting and a reduced voltage for normal running.

Also, different Pertronix Ignitors (Ignitor, Ignitor II, or Ignitor III) all have different recommended coil resistance by Pertronix. My Ignitor III is recommended to use with a coil of .4-.8 ohms.

 

[Bored&Stroked]

I run the BERU COIL ZS 172 coils on Harman-Collins dual-coil ignitions . . . they've worked flawlessly.

 

[petehoovie]

I run the BERU COIL ZS 172 coils on Harman-Collins dual-coil ignitions . . . they've worked flawlessly.

 

[Scotty's 52 F3]

Here's some info I found. https://ratwell.com/technical/BlueCoil.html

 

[glennpm]

Here's some info I found. https://ratwell.com/technical/BlueCoil.html

Good summary.

I think without disassembling one of the coils with higher resistance, is that there is no resistor component in them. The higher resistance I believe is by using lighter gauge internal wiring. With smaller gauge wiring, the heat would be evenly distributed inside the coil versus a local hot spot if a resistor was used.

 

[JayChicago]

No direct knowledge, but I thought that too. Why would a manufacturer need to use an internal resistor? More likely they just adjust the design of the coil itself.

 

[Bored&Stroked]

Link:

https://www.amazon.com/Beru-Ignitio...plications/dp/B007WR6D3M?tag=atomicindus08-20