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Starter Motor Trigger Cable Sizing

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals

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Evening HPA

Quick Question about choosing the correct Starter Motor Trigger Cable, I am in the process of Wiring a Life Racing PDU34A into a 1984 Porsche 928. I have worked out all my correct Amps which stock components will draw and the Starter motor is on a boarder line, test showed Inrush 0.07s max of 21 amps then consistent to 6 amps there after am I correct in using a single 16 AWG Spec 55 wire or to be on the safe side run 2 x 16 AWG outputs.

hope to hear from you soon

Regards Liam

After looking at a few charts and rules of thumb... a single 16 AWG should be fine.

Obviously you want a short path, and from dash to starter via a bulkhead should not be a big distance. Also, it's only in use for a few seconds, and Spec 55 should take a tiny bit more heat. And also, you can set your PDM to trip over 21 amps, so fairly safe.

Life's gear has some awesome inrush control/soft start strategies. In all honesty I'd be comfortable controlling, and do on my own vehicles, using 18AWG tefzel in those situations.

P.S. I don't recommend trying to limit inrush current yourself by way of setting a hard 21 amp target. Use the fancy software how its meant to be :)