Why do Ferraris use spark plug extenders with specific resistances? In the 308 days Ferrari used an extender to reach down to the spark plug that is about 2000 ohms. The 550 and maybe the 348/355 use fancier 90 degree extenders that are 5000ohms. Other cars like my chevy truck use wires with a terminal boot right to the top of the plug with no resistance other than the plug wire. Why does the ferrari secondary system have the resistance of the wire and the resistance of the extender?
Very common through the entire continent of Europe. Since they invented the car and invented the sparkplug one might ask how come the upstart Americans don't use them? And very few of the 308s used a resistor connector. Infact until Motronics were adopted they were the exception, not the rule throughout the product line.
Because your chevy truck's plugs aren't at the bottom of a deep, hot blind hole -- my 4-valve Honda Civic uses plug extenders for the same reason. Is an interesting point about how the impedance seems divided up differently between the wire+extender+plug on various manufacturer's systems and depending on model -- e.g., a TR uses a non-resistor extender.
Yes I'm trying to understand the theory. Fiber wires high resistance to decrease RF interferrence but break down fast. Sprial core wires the current thing 500 ohms/ft typical wire today to supress RF interferrence. So why does Ferrari/audi etc. use I guess a new standard sprial wire at 500 ohm/ft then tack on 5000 ohms at the extender? The chevy seems to have fine RF suppression with a wire terminated at the plug top.
