Replace alternator with higher amperage

[Chris]

And my point here Rob (good analogy btw) is that when you fit a bigger engine and someone says 'you'll need better tyres' - without knowing what is already fitted is simply a shot in the dark. You see here, we aren't talking about a Fiesta and a Zonda in truth. We're talking about a Fiesta and Mondeo. 80 am to 100 amp MAY well be within the spec of the original cable but without knowing, you're guessing. Simply chucking a bigger cable on is not going to do any harm. But it could also be a waste of time. I did mine today because I was so utterly bored I couldn't think of anything else to do. How's about that! I had some 50mm at just the right length so I threw that on.

The point is you MIGHT need better tyres.

 

[IRLGW]

The point is not will I need bigger tyres but is will a 100 series alternator fit straight into an 80 without any mods?

 

[Firewout]

Have look at this wire calculator.
it gives the recommended wire for a given length and current. If the diameter of the alternator cable is bigger or equal than the recommended wire, you're good to go.

http://www.bulkwire.com/wireresistance.asp