[Brylee]

I am planning on changing my alternator, and i am planning on getting sub-woofers.

The car will need 1000 Watts just for sub-woofers.

Are all alternators the same output? (i rather not have to buy an added electricity source for sub woofers.

What would be max WATT's i could use for two 12" sub woofers, on the alternator? (If all alternators are the same output)

 

[pony killer]

I don't have a system in the g8 but used too in other cars and I've never had to change my alternator over a 1000 watt amp. I believe mine was 1200 and I gotta add that I had a full one fared power cap. So maybe that was the difference maker. I was pushing two Rockford power series twelves and clocking a steady 146 db. Highest was 149.0 .

 

[Kylemacc1]

I'm running 3500 watts right now on 2 12s in my g8, stock alt and battery and I never draw less than 13.9 volts on idle so you will be fine.

 

[dB_Outlaw]

If your battery is old, I'd consider replacing it along with adding the system otherwise I wouldn't upgrade my electrical system unless I knew there was dimming after the system was installed.

Afterwards, if there's dimming, upgrade your "big 3" wires and re-check. If there's still dimming, upgrade your alternator to a HO one. There's places online that sell HO alternators or any alt. shop can probably rewind your stock to increase the amperage.

Just because your amps required a certain fuse rating (e.g. 200A), doesn't mean they're going to draw that much power constantly. You'd be lucky if you pull half of the listed fuse rating, even at full tilt.

There's always been a big dispute over cap usage. I'm from the, "they're worthless", camp. Caps are bandaids, HO alternators are solutions.

Never run the system when the car is off, that will quickly drain your battery, even at low volumes.

 

[dB_Outlaw]

Here are some HO alternator companies for your consideration (in no particular order):

Stinger
DC Power
Ohio Generator
Mechman
Excessive Amperage
PowerBastards

 

[Les]

I got a 1500 watt 10 subs added with sony amps and I didnt have to change to alternator and I have no lights dimming an d my alternator is stock it will handle it no problem.

 

[Netfly]

My first choice is to find a local alternator rebuilder and have him assess your system. A knowledgeable alternator tech can tell if you need a bigger alternator or can get more out of what you have. I'd rather keep stock and rebuild with better components when possible. It requires a better diode pack and a coil with more windings, but some cases can't handle it. Sometimes an under-drive pulley can be used to get more power at idle. The power output is well off its rated value at idle.

 

[dB_Outlaw]

I always heard that an under drive pulley is bad for stereos because it reduces voltage.

 

[Les]

My first choice is to find a local alternator rebuilder and have him assess your system. A knowledgeable alternator tech can tell if you need a bigger alternator or can get more out of what you have. I'd rather keep stock and rebuild with better components when possible. It requires a better diode pack and a coil with more windings, but some cases can't handle it. Sometimes an under-drive pulley can be used to get more power at idle. The power output is well off its rated value at idle.

I agree take it to a specialty shop and have them rebuild it to what you need. We do it here in Canada

 

[Netfly]

The voltage is fixed by the regulator, built into most alternators now, The current output is what drops off as the rpms fall below 2000. See the chart half way down this page for a good idea of how most alternators work. It's a decent read too.
http://www.pirate4x4.com/tech/billavista/Wiring/Part2/#performance

 

[4d00rV3tt3]

well IMO if you build the system up correctly with a capacitor than you shouldn't have a huge problem.a good rule of thumb was 1 fared cap for every 500-600 watts. I used a 2 farad on my system just to ensure I had enough and never had any problems. the alternator can be checked easily with a multimeter and turning on all loads, ac lights radio rear defroster etc. if your still in the high 13 to 14 V range than no worries. . also you can check the battery with a multimeter, check the voltage when starting the engine shouldn't drop very much from 12.6 volts (optimum system operating voltage) maybe as low as 11 but anything below 10 id start looking at a weak battery. hope this helps.