4 replies to this topic

[croc7]

What is nominal ohm measurement per foot? 5000?

[Steam]

It depends 9n the type of wire. Carbon string silicone is typically 4000 to 6000, the newer stainless wire wound are 1300 to 1600. Obviously copper is as low as possible.

Edited by Steam, 03 April 2024 - 07:00 AM.

[timmy850]

A really good lead is under 2K from cap to plug. 

2-5K is decent

Much over 5K I'd think about getting new leads

[mini13]

don't confuse low resistance with a " good spark"

 

yeah about 5k per foot is typical foe normal carbon string cables

 

the assumption is often the lower resistance the better... but system resistance has an effect on length of spark... its a whole topic on its own as, as your dealing with pulses, not steady state stuff...
essentially with very little resistance in the system, apparently its possible for the spark to be over and done before its really had time to do much ignition... with too much resistance, you get to the point where theres not enogh energy to maintain a proper spark...

 

with modern lean burn engines, resistance has gone up in systems so the spark is longer so it has a better chance to ignite lean mixtures ( and some manufactures have even gone to multispark systems etc but lets not go there)

also with some low resistance leads, they use things like spiral cores to introduce inductance, which with pulses has a similar effect to resistance... with puses and signals you have impedance in systems rather than resistance ( it all gets involved with leading and lagging currents for capacitance and Inductance,)

anyway.... about 5k per foot in the wires.... and about 6k in the plug is normal, and pretty optimal.
 

[ACDodd]

I dissagree I find optimum performance is less than 5k ohm. I use leads that total about 3 to 4kohms between coil and plug combined. Use no resistor plugs on conventional systems.

Ac