I'll be doing a big 3 upgrade in my car within the next couple weeks.
I'd like to know if I'd see any difference between a 4 and 0 gauge cable?

My alternator is rated at 75A, while the 4 gauge cable at 150A and 0 gauge at 300A.

Should the 4 gauge be enough or should I get the bigger one?

 

0 gauge

 

while your at it get a new alternator. If your running anything that really needs 4 or 0 guage 75 amps just ain't gonna cut it.

 

I don't think I need a high output alternator since I'm only planning on running a 500W rms system. Stock one should be enough.

 

I had a 2000 neon which has a stock 85amp alt. I was only running a total of 500wrms and even with a 3farad cap my headlights dimmed so much they looked like strobe lights with the system cranked. I would definately suggest 0ga big three and be prepared to shell out $$$ for a ho alt as I have a feeling you will have problems with any system at all with only 75amps.

 

If your only running 500 rms just use the 4 guage it will be plenty. With that power level there will be no difference. 4 guage will handle up to 1000rms on a 17 ft. cable. If your having problems like 420 was having it's because your alternator is NOT strong enough. No cap no matter how big will stop your lights from dimming. The lights dim becasue there is not enough current in the system to run everthing. A cap is a storage device it does not add current to the system it only keeps a consistant voltage for a short burst then recharges.

 

IMO 0 GA would be overkill. 4GA would be more than enough for a Big 3. However IMO and my personal exp the BIG 3 is more hype than anything. The best thing I done was upgrade the ground wire from 8GA stock to 0GA and a bought decent battery terminal.

 

Check the size of your factory wire. On my Golf it is 4AWG stock. With a 75A alt, I do not think you will benefit with a wire upgrade anyway. Your factory wire probably is oversized for your alt to begin with. So IMO, it would be a futile waste of time and resources.

 

i'd put money it's 8 guage the factory alt is only 75 amps. The manufacturers don't waste money if they don't have to. It's also true that any change will be almost non existant as he only has 75 amps to begin with. My sub amp only makes 600 rms and is fuse rated at 60 amps.If he turns his system up and if the amp actually makes 500rms his alternator is going to be the cause of any current/voltage or lack thereof problems.

 

I got a quote for a high output alternator. 140A for 325$ + shipping
Kind of expensive for such a 'low' amperage.

I'll go with 0gauge cabling, just in case down the road I do get the new alternator.