Dual alternator setup
 

For my 2000 Monte Carlo I want to upgrade to dual alternators to keep up a with a 11,000 watt stereo system I will be adding. DC alternators can make me a 270 or a 390 amp alternator with bracket. I will have a 160 amp primary alternator and a 270 or 390 as second alternator. Can the 3.8L V6 engine handle this, what will happen if I add the dual alternator setup? Such as fuel efficiency at take off, rough idle, or anything else?

why not just go with the 390 and 2 batteries? sounds like you do that and call it a day. the fuel efficiency will go down, because its rotating one more pulley. it'll be able to handle it but you will lose fuel efficiency and engine power.

What do you have to have 11000 watts

There was recently a thread just like this on here.

Of course the engine will handle it- any normal engine could handle spinning a second alternator- you're just taking more power away to be able to drive the wheels, thats all. Idle speed shouldn't be an issue either- the 3800 has tuning options to let you set it the idle higher/lower.

As far as fuel efficiency- spinning a second alternator seems rather minimal compared to all the weight you're adding. Assuming you have multiple subs, a very thick box, tons of heavy cabling, multiple batteries, multiple amplifiers, and all the bracketry and the second alternator. It seems like fuel efficiency isn't a main concern if you're ok with the fuel efficiency lost by adding all that other extra weight.

As I mentioned in the other thread- do you really need that much alternator? Are you talking 11k RMS? I've just seen a lot of pretty hardcore setups run just fine off two (or three) good batteries, and a single HO alternator. Its not like you're going to be driving around with the thing playing and using the full 11k watts constantly anyways- I can't imagine you'd be using it to its full potential more than just occasionally or at a db contest. I used to run just under half that power RMS in my monte- and even that was something I certainly couldn't go around playing all the time at full blast.

Between potential hearing damage of being constantly exposed to 150+ db, police attention, disturbing other drivers/homes/businesses, and making it harder to drive (mirrors all shaking so hard you can't see out of them)- I just couldn't see using the system to its full potential all the time (and thus warranting an electrical system that could support such use).

here is the current setup
http://www.wowelectronics.com/2000montecarlo.html

That is the OP's car? If so, it makes me laugh a little that fuel efficiency from adding a second alternator is even remotely a consideration- that thing is packed with equipment!

yes that is the car they posted a link on a previous thread and I believe that they work there the new system is going to be even bigger from what they said
here is the Link
https://montecarloforum.com/forum/sh...ad.php?t=26156

Well I will be adding 5 Kinetik KHC2400 batteries in the trunk and a KHC1400 or KHC1800, which ever fits under the hood. To keep up with 11,000 watts, my alternator would have to put out 765 amps. I decided to go with two 390 amp alternators, if I can fit a dual bracket under there. I decided to go with 11,000 watts because in my 2010 camaro...

https://www.youtube.com/watch?v=_nrVP4QKf8Mhttp://i1113.photobucket.com/albums/...fee/Alt_20.jpg

... I put in four JL Audio 13W7 subs and it's about 4,000 watts for the subs alone. In my monte carlo I am using Soundstream's new X3 15" sub which is 4,500 watts musical and 10,000 watts each for a 2 second bass burp. The amp I'm getting cannot get up to 10,000 watts, but if I wanted to I'd need like 10 batteries. Anyway, I decided to go with two of the X3-152 subs with is 9,000 watts and the rest are my other speakers just so my two subs will sound like nine.

The batteries, amps, speakers, etc will add up to 750-800 lbs. My fuel efficiency should stay the same. Mythbusters made an episode about fuel efficiency and adding weight doesn't really effect, just getting up to the speed eats the gas. So I will avoid city driving. The woodward cruise might kill my wallet lol. DC alternators will make my 390 amp alternator for $1150, So I will get two. I must be crazy.

What amps are you using.

I dont think you need 5 or 10 batts. maby 2 or 3 thats it.

I'm using 2 of Soundstream's new X3 amps the X3.71 about 4500 watts at 14.4 volts. Also 3 Soundsream Reference 4.920. The 4.920 is a 4-channel amp. So I will be using 2 of 3 amps at 4 ohm which is 145 watts per channel for 8 channels. The third amp is running at 2 ohm with 215 watts per channel for 4 channels. Yes I need it. In order to power my system I need the battery power to keep up with it. A guy at work only had two batteries for his 4 Memphis 15" mojos on one amp and it played for 1 second then shut down. When you get into high powered systems, you need it. I could get by with maybe 4, but I want to listen to it for long drives, but I doubt it will be at 100% volume all the time. I am wondering if dual alternators will fit in there. It's tight down there.