Would a stock WRX be able to run this?
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This is a discussion on Would a stock WRX be able to run this? within the Interior Mods forums, part of the Tech & Modifying & General Repairs category; Hello, first off I dont have a WRX but will be getting an 03-07 within the next 2 months. I ...

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    Registered User Whoa!ShutItDown's Avatar
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    Would a stock WRX be able to run this?

    Hello, first off I dont have a WRX but will be getting an 03-07 within the next 2 months. I am already building a system for it but Im not sure if I will need a second battery or bigger alternator. Heres everything that I will have when its complete,

    Alpine CDA-9884
    Alpine SPX-13REF
    Alpine SPX-17REF
    2 - Alpine SWR-1222D
    2 - Crunch P1400.2
    Boss Audio CAP3.5S
    And eventually an Alpine PDX-4.100

    I am planning on running 2 1/0 wires for power and ground and using distribution blocks. I know it seems kinda unnecessary to have 2 amps for 2 subs when I can have one but I cant find a 2 or 4 channel amp that puts out enough with the correct impedence, and 1/2 ohm mono blocks arent too common. Thanks for any input

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    He simply abides. SD_GR's Avatar
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    The stock system uses a 75A alternator to charge a battery rated at either 48Ah or 52 Ah, depending on the car's gearbox. By the time you buy a car the majority of cars on the road may no longer have the stock battery, so the Ah rating of the stocker may be a moot point.
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    Registered User SkeetsWisconny's Avatar
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    i'm going to guess yes... I don't know specifics on ur stereo equiptment but .... I have an Alpine deck, 6 1/2 in Boston Acoustic Ralley Series components in all 4 doors (rear doors had to be custom fit for larger than stock speakers), 3 MTX 10's in a closed box, two 1 farad caps behind an MTX 4 channel and a MTX sub amp that puts out at least 1500rms. I dim the lights when I'm pushing it hard with a stock battery/alternator setup and I'm hoping my alternator lasts. I don't listen to the stereo as loud as I used to so i'm hoping it lasts. I would think about getting a quality stereo battery at the very least as I have even considered it. I heard running two batteries can be a PITA. Good luck w/ur setup!

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    Quote Originally Posted by Whoa!ShutItDown View Post
    Hello, first off I dont have a WRX but will be getting an 03-07 within the next 2 months. I am already building a system for it but Im not sure if I will need a second battery or bigger alternator. Heres everything that I will have when its complete,

    Alpine CDA-9884
    Alpine SPX-13REF
    Alpine SPX-17REF
    2 - Alpine SWR-1222D
    2 - Crunch P1400.2
    Boss Audio CAP3.5S
    And eventually an Alpine PDX-4.100

    I am planning on running 2 1/0 wires for power and ground and using distribution blocks. I know it seems kinda unnecessary to have 2 amps for 2 subs when I can have one but I cant find a 2 or 4 channel amp that puts out enough with the correct impedence, and 1/2 ohm mono blocks arent too common. Thanks for any input

    There's a few things you can do differently. You only need 1 mono block amp running at 1 ohm to run two Alpine Type R subs. You want to get DVC 4 ohm Type Rs, rather than the DVC 2 ohm. They're also on ebay. Alpine SWR-1242D.

    There are plenty of amps that will do 1000 Watts RMS at 1 ohm. Cadence TXA-1000D is a solid choice. There are also plenty of hifonics amps that do it as well. Elemental Designs 9.1 does around 1400 Watts @ 1 ohm if you're looking for some overkill.

    You'll also want to run those components off of an amp, which you mentioned eventually doing, so that's good.
    Don't bother with the capacitor. It wont help you at all in this case.

    So I'm assuming you'll be running a single 1000 watt RMS amp for the subs and one 400 Watt RMS amp for the speakers.
    Power = Volts*Amps
    1,400 watts total.
    At 14.4 volts (assuming you have done/will do the big 3 upgrade you will be getting 14.4 volts...which is important) you have...
    1400=14.4*A
    A=97.2

    So with a stock alt of 75 Amps, when you really want to push the system you will be limited. This of course depends on a bunch of things. The kind of music you listen to, the box you put it in, etc. But generally speaking, when you attempt to run this system near full tilt on bass heavy music, you will experience headlight dimming and be limited in your subwoofers output.

    You would want to get a high output alternator if you think you will run this at high levels. If you will not be running full tilt on bass heavy music...then you'll be fine. Just make SURE you do the big 3 upgrade or the problem will only be exacerbated.

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    Quote Originally Posted by SkeetsWisconny View Post
    i'm going to guess yes... I don't know specifics on ur stereo equiptment but .... I have an Alpine deck, 6 1/2 in Boston Acoustic Ralley Series components in all 4 doors (rear doors had to be custom fit for larger than stock speakers), 3 MTX 10's in a closed box, two 1 farad caps behind an MTX 4 channel and a MTX sub amp that puts out at least 1500rms. I dim the lights when I'm pushing it hard with a stock battery/alternator setup and I'm hoping my alternator lasts. I don't listen to the stereo as loud as I used to so i'm hoping it lasts. I would think about getting a quality stereo battery at the very least as I have even considered it. I heard running two batteries can be a PITA. Good luck w/ur setup!
    Two batteries would not help in this situation unless he wants to listen to the system for extended periods with the car off.

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    Registered User SkeetsWisconny's Avatar
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    I had my alternator on my camaro beefed up from 80amps to 180amps and it did wonders for the stereo's power but i did experience some belt squeaking issues. I'm thinking this was caused by the beefy alternator but i'm not positive I wouldn't go to crazy on the alternator upgrade if u go that route just in case but that combined with a good stereo battery would definately help no doubt

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    Registered User SkeetsWisconny's Avatar
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    ... talk to some good car stereo installation places and they should be able to help u out as they are the specialists in this area and will be able to test ur setup as well if u want, good luck

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    Talking to some local shops wont necessarily hurt, but be careful...only talk to a place you trust. I've heard "specialists" tell me blatant lies or things that are painfully wrong.

    I am a car audio specialist myself. I've laid the math out for you right there and you can clearly see the result.

    Also, another decent amp is an audioque AQ-1200D. That is a VERY solid amp at a great price ($250). Very happy at 1 ohm.

    Let me give you a specific example. My car has a 120 amp alt. I have not done a big 3 upgrade. It is a 3 liter engine (getting a new WRX soon, hence joining the forums to start learning more about it). I have a cadence TXA-1000D amp with two Elemental designs 13Ov.2 subs. Aftermarket HU with no amp. In other words, all thats there is really that 1000 watt amp. When pushing the system I experience headlight dimming. Most of that would be eliminated by a big 3 upgrade. The math:
    1000=12.4*A
    A = ~80 amps
    I used 12.4 Volts since most cars without a big 3 only operate at 12-13 Volts. post big 3 you should see 14.4 and a higher current capacity.

    So, with my 120 amp alt in a 3 liter car, I experience dimming. That is a direct example that with your 75 amp alt with a more demanding system you will experience some issues without an alt upgrade. You can get by without it. It will sound great for sure. But you will definitely get headlight dimming, I can tell you that. But really, headlight dimming isn't such a big deal. Definitely at the very least do the big 3 upgrade. And of course, only use one amp for the subs, not two.

    And again, a second battery wouldn't help unless you listen to it with the car off often. A better battery doesn't hurt, but the main issue is the alt, not the battery. Think of the alt as the waterfal, and the battery as a bucket. You are drawing from the bucket, technically, but the waterfall is what keeps that bucket full. Get a bigger bucket and it will take a bit longer to run out of water, but you'll still run out. Get a bigger waterfall and you wont run out of water.
    It's a silly analogy but it helps I think. You'd want a bigger alt, not a second battery.

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    Quote Originally Posted by SkeetsWisconny View Post
    I had my alternator on my camaro beefed up from 80amps to 180amps and it did wonders for the stereo's power but i did experience some belt squeaking issues. I'm thinking this was caused by the beefy alternator but i'm not positive I wouldn't go to crazy on the alternator upgrade if u go that route just in case but that combined with a good stereo battery would definately help no doubt

    A higher output alt will not damage your belts or cause squeaking. If it was not installed properly it could cause belt slippage, but that is true of any alt, not just HO alts. You will need the proper tension to maintain traction.

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