The V8 Owners Forum -

As per title really, what amperage/gauge wire should I use for my starter? Had a look to see if there are any stickers or ID on but I couldn't find anything. It's a RV8 3.5 on carbs. Was thinking around 160amps to be safe?

Bigger the better !!

Get something of at least 35mm^2 cross section area if running it less than 600mm, beyond that go up to at least 50mm^2

Current capacity should be greater than your batteries cold crank limit to reduce voltage drop as much as possible. Don't know how that relates to the numbers above since I've never done the maths. Probably wise to assume the starter can stall so use it's stall current as a starting point, don't have the numbers around but a typical V8 starter is a Lucas 3m100 with a stall current of about 500 amps.

I've found an american site with a calculator - http://www.powerstream.com/Wire_Size.htm - your 160 amp cable would lose half a volt in a car like my MGB.

Dave

35mm^2 is more than adequate and certainly larger than most OEM's will use.

Handiest stuff to use is welding cable. It's well insulated and very flexible. And multi strand cable like that also has a higher current capacity than lesser stranded more rigid conductors.

I cant see any normal car requiring anything bigger, not even a big diesel.

Unless you are wiring it expecting the engine never to start so you'd be cranking it for hours.
Although the starter would probably fry first.

Welding cable, seen that advertised and wondered why I would need it....now I know, thanks.

It does come in different sizes, but it is good stuff.

Makes great jump leads too.