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View Full Version : PRoblems with car dying out on a 1000 watt rms w/ 2 Type Rs


clutch1
03-16-2007, 09:38 PM
A buddy of mine has a 92(ish, I forget exact year.) Cavalier Z24 with a 3100 V6 engine.
He's had 2 12's in it for a while, but recently upgraded to two Alpine Type R's running on a 3000watt (1000 RMS) amp. It was ok for a couple days, but now it tends to die out when the system is pounding, but otherwise run good.

He disconnected the + battery for the amp and it's been running fine since, and the battery tests just fine at the shop he took it into for a quick look over.

So the question is..
does he need a new higher output alternator to keep up with his system?
or would say, and Optima Yellow Top cure it for him (this was suggested by his bro).

If it's an alternator he needs, how would the first one on this page work? And what version would he want probably? 105 amp? 160 amp? 200 amp?
http://www.motorcityreman.com/high-amp-alternators-chevrolet-gmc-cavalier.html

antichrysler
03-16-2007, 10:05 PM
It's definitely the alternator. As the amp gets louder it draws more current which lowers the voltage off the alt. When the voltage gets too low it shuts down your car. But the 160 amp I think would be pushing it. Remember, at 1000W RMS (assuming it actually does that) it's probably 2000W peak, so 2000W/14V is approximately 140A. Keeping in mind you still have to run any other electronics in the car, plus charge the battery, and the alternator only puts out the max current when the car isn't idling.

clutch1
03-16-2007, 10:10 PM
So.. would he want about a 150 amp alt?
or do you mean pushing it by" just squeaking by with enough power being put out?"

greenbastard
03-16-2007, 10:33 PM
buy a capacitor. i'm only running 700watts in my alero and the lights dim out when the system pounds. this will store energy for big hits and your alternator and battery will thank you. it wouldn't be a bad idea getting a new alternator.

SweetNLow
03-16-2007, 11:05 PM
caps are crap

Ryan from Ohio
03-16-2007, 11:15 PM
I wouldnt listen to anyone who has posted in this thread previous to this post. There knowledge on electrical systems is null.

The alternator might be the culprit, but there is another thing to look at. The wiring for the charging system. Usually its about 8 ga or less. From the alternator to the batter, battery to ground, egnine to ground. Thats the big 3 and I highly advise he starts his upgrade process there as he will need to regardless if its the alt or not!

Basicly whats happening is the amplifier and the car is pulling more power than can be produced. When this happens the alternator is literally burning up and is at 100% capacity. The voltage drops, the battery isnt being charged, and actually its taking up the slack. So eventually the alternator WILL burn up and he will suck the battery dry leaving him stranded. Been there, done that a few times:)

Capacitor would be a benefit only if you have the power in the beginning. If your already having a problem, what good is it going to be adding ANOTHER item the alternator must charge? Its in a constant charge/discharge state...

So to recap. Do the Big 3 first with 4 Ga. If that works cool, if not get another alternator. 160 should do it. 105 is stock.

And for figuring current draw, use the RMS. Take the RMS/13.8 and thats the amperage. Since music is transient you wont always be at that RMS number or current draw...

clutch1
03-16-2007, 11:51 PM
Right, I told him caps are pretty useless and are only for like dimming lights and small things like that, he said he didn't think it'd work, too.

I'll tell him to upgrade that wiring, sounds like it should be a reletively easy task if I can find all the wires.
But what exactly is the "engine" ground that would need to be located/replaced?

pimpalero2003
03-17-2007, 04:47 AM
so far every thing is good the alt should b fine. caps are 4 morons! but best thing is a dry cell batt it will do better then red or yellow but also cost a lot more. also if he has every thing where hes going 2 keep it cut the power wire just enough 2 plug n the longer it is the more power he loses! also look into solinoids

Stanl3yX
03-17-2007, 09:14 AM
i stepped up to a high amp alt after my system kept cutting out, and it never cut out afterwards. eventually i added a 5 farad cap just because i got it for such a steal

antichrysler
03-17-2007, 01:22 PM
Ryan from Ohio basically did a good job repeating what I said... The reason I suggested using the peak power for measuring the size of alternator you need is because RMS is pretty much average power. Plus, if it's putting out 2000W peak it's drawing MORE than that from your alternator.

Caps do make a difference. The purpose is to give you spikes of voltage. They've been used in camera flashes for years, which isn't much different from an amp that needs a sudden burst of power.

Ryan is right about the cables. If you put a new alternator in you're going to need new cables anyways. The resistance of the 8 or 12 gauge will cause a bigger voltage drop than say a 4 gauge wire. Plus you get a shorter distance which also helps.

The 160Amp should be okay if you're using a decent cap.

Ryan from Ohio
03-17-2007, 08:32 PM
Im still not digging the max power to amperage calculations.

Music is transient, so theres only a .01% chance of hitting a max power rating. So figuring that is null. Go off the RMS. If your amp has a 40 amps of fusing, figure on adding 40 amps to about 70% of your current alternators capability.

With Motor City Reman: They are good people, but for whatever reason many have had issues with their Alternators because for WHATEVER reason, they put on a pulley that is smaller than the stock pulley. It creates less power with the smaller pulley, so I suggest removing and keeping your old pulley.

antichrysler
03-17-2007, 09:56 PM
Well with the max power what you gotta realize is that the amp isn't 100% efficient, meaning that it draws more than it puts out. Since RMS is basically what the amp can continuously put out, that doesn't factor in bass notes (i'm assuming the amp is for his subs), that is why you need to use max power instead of RMS. I agree that there's a 0.01% chance of hitting the max power rating (realistically we both know that amps are over rated for what they put out), but the fact remains if he does hit that one 0.01% chance there's a possibility it'll make his car die out again. A well designed system always has a factor of safety of atleast 1.5. Meaning the alternator should be able to put out 1.5x what the system requires for it to be completely stable. Keeping in mind there are other things in the car such as rear window defrost, ABS, heater, head unit, etc that are also all drawing from the alternator.

Ryan from Ohio
03-17-2007, 10:11 PM
Ok,

Let me illustrate. Using your ideology I guess its not acceptable to run 8000 WRMS of a 300 amp alternator?

Cause were doing it and doing it with ease...

Plenty others are as well.

Max ratings are meaningless. Even if your system EVER hits its max rating, its literally for a nano second. So fast in fact, even if you had a 5000 amp alternator it wouldnt help...

pimpalero2003
03-17-2007, 10:14 PM
that when u hit the shit u have the extra batts

sound_xtreme
03-17-2007, 10:22 PM
not to mention, many manufacturers rate their max at 14.4 and above.

antichrysler
03-18-2007, 01:10 AM
I don't think it's even possible to get a car amplifier that can put out 8000W RMS. Plus you have to realize the numbers I'm using are on amps that actually meet the spec. Buying a cheap Sony X-Plode or some cheapo generic amp the rating is different. That's when they rate based on that power output for a nano second before it blows itself up. That's when the RMS rating is realistically the peak rating. Anyone can put an arbitrary number on an amp.... When you get into good quality gear like Phoenix Gold they write what the amp can actually do.

MixtapeMessiah
03-18-2007, 01:13 AM
Get hids and u wont have ur headlights dimming, and run a cap for ur system since ur pumpin out that much power. Higher output alt would be a good investment too.

Ryan from Ohio
03-18-2007, 09:51 AM
Your right, its not a single amp its two 4000 WRMS amps. Believe me, they are slightly under rated...

I gotta head up to the build today. Placing 3 DEKA Intimidators into the mix. two MM4000.1s, one MM8000.5, and one 1 MM100.4...

So were not dealing with Sony amps... ;)

Hopefully in two weeks we will be driving around Toledo terrorizing the city ;) 150 dB plus. Hell were doing 150.x with a 100 amp battery charger...lol

antichrysler
03-18-2007, 01:22 PM
lol that's some good terrorizing.

cheers

Ryan from Ohio
03-18-2007, 06:30 PM
Oh ya...

Put it this way, 3/8" windshield flex. Thats NO BS either...

antichrysler
03-18-2007, 07:15 PM
is that in an alero?

Ryan from Ohio
03-18-2007, 07:44 PM
nope, 94 regal 4 dr.

antichrysler
03-18-2007, 08:21 PM
ahh sweet.. I wouldn't mind seeing some pics of the set up when you're done