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new amp needs

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=124741
Printed Date: May 14, 2024 at 11:11 PM


Topic: new amp needs

Posted By: acetone
Subject: new amp needs
Date Posted: November 30, 2010 at 12:26 AM

I am getting a new amp its a autotek mm4000.1 its 4000rms I have a 97 vw gti and I was wanting to know what all I need/get for my car to make it work for every day use
I have got 0/1 gage wire On the way for the big 3



Replies:

Posted By: oldspark
Date Posted: November 30, 2010 at 2:09 AM
A 400A alternator.




Posted By: soundnsecurity
Date Posted: November 30, 2010 at 11:57 AM
that is a huge amp, what subs do you plan on connecting to that amp?

in addition to about 2 or 3 or 4 extra batteries depending on how good they are, you will also need to upgrade to a serious alternator. im running the MM2000.1 in my truck and it sucks some juice even though i dont really play it that loud. if i do turn the volume way up for a competition, the amp can actually kill my truck while it is running because it simply uses every little bit of power that my truck can make. and that is just the MM2000. you want the 4000 so good luck with that.

and also be careful when you buy whatever subs you plan on hooking to that amp because it is only stable down to 2 ohms, so watch your coil configuration.

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Posted By: oldspark
Date Posted: November 30, 2010 at 8:33 PM
soundnsecurity wrote:

...you will also need to upgrade to a serious alternator
LOL - I thought that's what wrote.

As to adding another battery, acetone will figure out if its needed - whether the first sag, or the first stranding.




Posted By: soundnsecurity
Date Posted: November 30, 2010 at 10:03 PM
oldspark wrote:

soundnsecurity wrote:

...you will also need to upgrade to a serious alternator
LOL - I thought that's what wrote.

As to adding another battery, acetone will figure out if its needed - whether the first sag, or the first stranding.


eh, i was simply agreeing with you and elaborating. and extra batteries are pretty much needed when you are running an amp like that unless he can find an alternator that will output 250 - 300 amps at idle without putting too much stress on his engine at idle.

i have a customer at the moment who wants to run two of these autotek MM4000.1's on 2 RE audio MT series 18's. when we looked at the specs and made a few calls to the manufacturers we decided to recommend him a 250 to 300 amp Ohio generator alternator and at least 6 kinetic 3400 series batteries for the total system requirements. and this was next to minimum for the amps to run properly for a daily driver system. and as we all should know, you can never have enough power to supply to your amps. more is always better.

those amps are beasts, and should not be taken lightly in any system. if you wanted something that would just drop in without modification then maybe you should have settled for a power acoustic 4000 or some other cheap amp that cant even come close to outputting its advertised power rating.

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Posted By: oldspark
Date Posted: December 01, 2010 at 12:07 AM
Understood SnS.

Yet again I am responding to underspecification, but I a assuming that since 4kW was quoted that that reflects an effective power requirement hence a 4kW alternator, hence ~400A for the sound system itself.

As to "too much stress" on the engine, the alternator simply replaces what it can - ie, total electrical load plus battery recharging.
Hence in this case 4kW or about 6HP...
That's the equivalent of an airconditioner which often have cut-outs for smaller engines at idle.

If acetone cuts the alternator at idle speeds (instead of cutting the audio), then at 4kW the vehicle battery is effectively cranking the engine as far as loading goes.
How long will acetone's battery last cranking a 4kW starter motor (though many starters are only 1-2kW), I don't know, but probably not long. Not that the battery would last more than a few weeks being used like that anyhow....


But since single 0/1G won't be enough anyhow, I assume there is more acetone has not specified.





Posted By: acetone
Date Posted: December 01, 2010 at 12:31 AM
Not sure if possable for my car but trying to run 2 250amps atls so I can get a total of 500 amps but not sure if I cab I have tryied contacting a couple places and im waint a responce but I seen that old spark said too much stress on,an engin how can u fix that problem or find out that itd too much im new to systems this large and thats y I came here for some help




Posted By: soundnsecurity
Date Posted: December 01, 2010 at 2:12 AM
actually not sure about how much stress a new alt will put on an engine its just something that was told to me by a friend of mine who rebuilds alternators. ive never seen it happen myself.

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Posted By: oldspark
Date Posted: December 01, 2010 at 2:56 AM
I did NOT say it was too much stress (how can I - I don't even know what motor?).

All I pointed out was that it's about 4kW for the amp alone (obviously), and from 1HP = 745W you can figure out the minimum power taken from the engine. Inefficiency will add its bit (the alternator may be 80-90% efficient - ask the supplier).

FWIR, aircons are about 5HP (3.7kW).


PS - Do not connect alternators together except when designed to do so.





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