Starter wire upgrade

[Lucas03es]

So im looking at upgrading the main power wire for my starter. It looks like the previous owner of my car ran like an 8 or 10 gauge wire to it, and I want to do a 4 gauge run just for personal ease of mind. Where does the other end of the starter wire go to? Im not sure if the previous owner did it properly, but it looks to run in to where the fuse block that bolted to the battery is at. I have relocated the battery to the trunk, would it be possible to just run the 4 ga. to the 1/0 ga. lug and bolt them together? I believe this would be okay, because the solenoid is on the starter, and it is activated by the 16 ga. black switch, correct? I hope this makes sense!! Thanks!!!

 

[luv2rallye]

I assume you mean you have a 1/0 ga running from engine compartment to battery positive in the rear. If so then yes but the connection terminal must be absolutely clean, tight, and have a large area of contact. If even 0.05 ohms resistance is there the starter won't work. You also need a cable from a starter mounting bolt to chassis and chassis to battery negative (all with same type of contact requirements). And remember in cold weather and/or heavy loads the starter can initially draw up to 150 amps so plan for this (150A thru a 0.05 ohm contact resistance drops 7.5V which will not allow the starter to operate). This is why the slightest resistance in starter cables or contacts is the #1 reason of starter problems.

Rather than measuring resistance of high current cables or cable terminals (joints) it's better to measure voltage drop across them when the high (starter) current is flowing. Anything higher than 0.5V must be fixed. Measuring resistance is unreliable and inaccurate (most meters don't go down to 0.01 ohms or less, and sometimes that high of current can even change the resistance, and nothing beats testing with the actual current flowing).