My question is if i run a higher amp alternator like a 130 or 140amp will i need to upgrade the stock wiring to the alternator or will it just work with the stock wiring?

 

The system only takes what it needs so you are fine.
If you feel to upgrade the starter wiring,etc so that the starter gets more direct power through new wiring then that is up to you.
I got a FD alt on my stock wiring with zero problems and I am going to a taurus alternator(130 amp) as I will be running a 6K amp for my sound system.

 

I have a FD alternator too changed my wire from alternator to battery terminal the 25 year old cable wasn't likening it car sees 13.9 on and 13.4 everything on

 

How hard is it to do the fd or Taurus alt conversion on an s4 ? Taurus alt sounds like the part would be easy to get at the junkyard.

 

The FD alternator is a direct bolt-on. The taurus requires some modifications. In either case, the wiring is different, and you'll need to source a pulley. There are writeups for this.

 

I'm surprised that nobody has come in and said that Famous "S" word.

 

Shitsnacks?

 

if you plan to use the output of the alternator then the 80A main fuse has to be upgraded to be rated higher than your alternator can put out, and in addition the charge wire gauge should reflect this and be upgraded to a wire nearly twice as thick.

otherwise what was the point of "upgrading" the alternator again?

in fact almost all of these high amp alternators suck ***, because they drag their *** at idle and most people don't need more than 60A to power the whole car even with an electric fan and rear defroster going(the 2 largest electrical hogs).