Caps, Alternators, and Cables oh my!

[xSomeguyx 10+ year member]

Ok, so I just got done finishing the install on my '03 Neon SXT, and I've got to say, it all sounds REALLY good. Here's what's installed:

Alpine MRV-F450 (4x50w, 1x200w sub)

Pioneer TS-D690R's (rear deck)

Pioneer TS-D170R's (front door)

Pioneer Deh-P520 head unit

Infinity Reference 1030W 10", in 1cu foot enclosure

Now the problem: when the bass hits a deep note, my lights dim. I've searched around, and so far the people who've had similar problems were given three options. Get better wiring, get a better alternator, or get a cap. The alternator that's in there already is supposedly rated for 160 amps, so I figure that ought to be enough. The wiring I'm using is 8 gauge, which should be enough for the Alpine, as it will only draw 50amps at most due to the fuse (they even recommend 8 gauge). As for caps, alot of people have told me that are a dirty, dirty gimmic for this sort of application.

So, what do you guys think? I don't have the gains up very high, they're at about 75% on every channel (front, rear, sub), and the sub isn't hitting THAT hard. I notice the lights dim a little when I hit the power windows or defroster, so that makes me lean towards the alternator not putting out that 160amps.

Thoughts? Comments? ANYONE?

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[indosia 10+ year member]

If your headlight dim for just a second and then come back,then your alt is fine. A cap near the amp will keep this from happining, because it will act like a storage tank for when your amp needs it. I would definitly suggest gettign a cap. Just stick it as close as possible to the amp and ground both the cap and the amp to a single piont on the chassis. don't ground the amp to the cap.

And turn the gains down, If your h/u has 4volt pre out, gain should only be up 25%-35%. for 2 volt pre out 50%. Gain is to so you can match the output from h/u to the amps input. it's not a volume control. h/u is volume control.

 

[btnhfan 5,000+ posts]

i would first upgrade the wires under the hood. that is what i did and it worked wonders for me. battery to alt, battery to ground, and engine to ground. its real cheap and works great.

 

[indosia 10+ year member]

Good idea, he's only running 8awg to the amp, so might not help that much.

 

[xSomeguyx 10+ year member]

Thanks Indosia! What size do you recommend? I'd think that .5 farad should do, but then again, I don't really have any exerperience with them. Do you think that I should upgrade the power/ground cables too, or should the 8 gauge cable be good enough? I'll take a look under the hood tommorow about the electrical cables too. Thanks!

 

[tommyk90 5,000+ posts]

I hate caps......

If you getting dimming with that size alternator and that size amp i think someone yanked your chain on the alternator. My alt is 90 amps and i'm putting out over 1000 RMS and get some dimming.

I say get your alternator checked out.

 

[indosia 10+ year member]

Ya, not likely a neon comes stock with 160amp alt. how bout 60 amp. .5 FARAD should work.

 

[paikiah 5,000+ posts]

upgrading wires under the hood?

Hmm, you gotta realise that it might be even better to have not just ONE body to engine link, but multiple points.

THis here is MY ground job (imagestation http://www.imagestation.com/album/?id=4287673739)

RED is the ground, BLUE is positive. I used 4 gauge, as I only have up to 130A of alt power and wire runs in the engine bay is short.

ground points:

1. Alt body

2. Right strut tower

3. Throttle body

4. Engine

5. transmission (not in pic yet)

DO i notice a diff? hmm, still dims..

 

[xSomeguyx 10+ year member]

Well, I did some digging and it turns out that it's only an 83amp alternator. **** the Dodge website! I did notice while I was in there though, that it looks like only 8 gauge coming off the alternator and to the battery. Anyone have thoughts on that?

 

[iceteebone 5,000+ posts]

try upgrading to 2 or 4 guage wire under the hood. if that don't work you have it already done so you can just swap in a new alt. go to the sounddomain forums and under electrical explanations there is a sticky thread that explains how to upgrade the big 3. it's very good and detailed.

 

[allyourblood 10+ year member]

is your engine running when the lights dim? if not, i wouldn't even bother. i'm running 400w off a 60amp alt. with zero dimming with the engine on, and only a little dimming when the cars off (and the system crankin').

abe m.

 

[xSomeguyx 10+ year member]

To allyourblood: yes, it's running. If I just idle it's pretty bad (especially something with heavy bass), but even when driving it's still dimming.

To everyone: after further inspection, the wires are even smaller than when I glanced at them earlier. The cable coming off the alternator is actually a little smaller than my 8 gauge for my amp, so it's probably 10 gauge, or just poorly insulated 8 gauge. The cable coming off the ground of the alternator is pretty tiny, it's a smidge smaller than a #2 pencil. I'm going to call up the dealership tommorow and see what they'll do about it, I don't feel like voiding my 7/70 extended warranty! Thanks for everyone's help!

 

[xSomeguyx 10+ year member]

Well, incase anyone is still watching this thread, I got a solution!

I mentioned the problem to a friend who does car audio, in hopes of snagging some cable off him to do the Big 3. He then promptly pulled out a .5 farad cap out of the back of his car, and told me to give it a try.

Guess what? I installed it and now there's no dimming. None. I tried turning up some Slipknot further than I'd ever listen to it, and I did notice it a little, but that was while the car was idleing. The motto of the story? Maybe a high-output alternator, or the Big 3 isn't always the solution!

 

[n2audio 5,000+ posts]

Theres always more than one solution to every problem.

There are also ways to cover up a problem w/o fixing it. Beefing up wiring and improving the alternator's ability to power your system is a FIX.

A cap is a cover up.

 

[allyourblood 10+ year member]

glad to hear the cap is working for you. make sure you still upgrade your wiring under the hood, when it's convenient. i assure you it can only help, and it's just so easy to do. set aside an afternoon one of these days, and get it done. good luck!

abe m.