The ground cable on my battery is a bit too small for my needs. Can I just add an extra 4ga cable to the -ve terminal and ground that to somewhere on the chassis, leaving the old grounds in, or is there something else I need to know?

Nope, thats pretty much it! Or you could replace the original ground completely but having both should cause you no problems at all!

Its also a good idea to upgrade the ground from the -ve terminal that goes to the alternator and the one from the -ve to the engine block, though this is not always nescessary. 8ga should be fine for the two other earth points, 4ga for the main chassis earth especially if you are running 4ga from the +ve terminal to the amp :D

Thanks.

Id love to upgrade the other ground cables but I cant afford any more ring terminals. All this servicing and repairing the car has left me broke.

yeh, just buy some ring terminals and some cable, and go crazy

if u want, u can go grab a piece of copper or something, and make a bus!!

i just bolted an extra 4 ga cable onto my -ve terminal. doesn't sfa, but eh, looks cool i guess :confused:

Yeah no need to take off the other grounds, the more the merrier.

I put in the extra 4ga ground cable. Now the volume goes to 54/62 rather than 52/62. Almost justifies the money spent to buy the cable and terminals...