Dumb question

[grannyknot]

On my 240 there is a 16ga green/white wire from the ignition switch to the back of the tach then becomes a black/white wire, also 16ga that goes to and powers the ignition coil. Would there be an advantage in changing those 16ga wires for 14 or 12ga?

16ga just seems kind of thin to power the whole ignition system.

Thanks,

chris

[SteveJ]

It's actually not a dumb question. There are two issues to consider: wire ampacity and voltage drop.

The stock 240Z ignition system doesn't draw that much current. There just aren't that many components involved. So the 16 AWG wire is adequate.

Voltage drop comes into play when you have DC voltages traveling along wire. I did a sample calculation for 16 AWG at 14 VDC traveling 10 feet in a circuit at 5 Amps. The voltage drop was 0.40 volts. (Voltage Drop Calculator)

[Captain_Zeros]

Speaking of voltage drop, there is a giant ballast resistor on the end of that wire next to the coil too!

[Stanley]

Suppose it was a non-stock ignition, MSD or CDI for example? Don't know how those are powered, but would those 16 GA wires still be OK?

[SteveJ]

I couldn't tell you without a spec sheet. I don't know how much they draw.

[grannyknot]

Steve, I was just about to ask the same question. I just looked it up and the MSD 6al standard or digital ignition draws .7 amps per 1000rpm so even at 6000rpm it's only pulling 4.2 amps, so still okay. But I guess if you are going higher in rpm and considering age of crimps and soldered joints then replacing the stock wires with 14ga would be more than enough?

I'm just staring at snow banks thinking how I can make my car better and more reliable...spring will come one of these days.

Thanks,

Chris

[SteveJ]

If the connections aren't solid, the wire gauge is not relevant. A bad connection will act like a resistor and drop the voltage to your ignition.