Hondaman

I have a couple of questions that I hope you can help me out with.

I have a 2001 GSR and want to add a new sound system to it. Currently I have(but not yet installed) a dual 4 ohm Alpine 10" type R sub with an Alpine MRP-M350 (200W x 1) amp for power. I'm adding a MB Quart Reference RAA4200 4-channel car amplifier (100 watts RMS x 4). In the rear I have a pair of the new 6.5 Alpine type R SPR-17LP speakers and up front I'll be doing a pair of component speakers. They are yet to be determined, but most likely Cantons/MB Quart or Alpine type X.

Question 1: Will my alternator be ok with this setup?

Question 2: How would I run the power wiring to the amps? I've heard I should do a circuit breaker instead of any fuses, but others say I should run one main 60 amp fuse then go through a dist. block and fuse each amp individually as well.

Thoughts? Opinions? Experiences?

b00gers

Question 1: Yes. Considering your alternator is only 4 years old and should still be in great shape.

Question 2: With those two amps, run a 4 gauge power wire from the battery to the trunk. Within 18" of the battery post, mount a fuse holder there. The fuse should be a combination of the Alpine amp's onboard fuses (40a) + the MBQ amp's onboard fuses (90a). It adds up to 130a, but I dont know about putting that big of a fuse...:thinking: I would wait on someone else'sinput on that

From the trunk, run a fused distro-block to the 2 amps. The Alpine amp takes 8 gauge while the MMQ can accept 4 guage.

TTT

Will, I'm not sure if I agree with you for #1. Considering most ff import cars have less than around a 115 amp alt to begin with, I believe adding a 100 + amp draw will strain the electrical system pretty badly. But now that I look at it, are you sure those fuse readings are correct? A 200 watt amplifier having a 40 amp fuse on it? If the amplifier is 100% efficient (which of course it is not),
power = current x voltage
200w = I x 14.4
I = ~13 amps

Since its not 100%, it is probably alittle higher, say around 20 amps. Seems kinda strange. Seems like the MBQ's fuse rating is high too. At any rate, assuming the fuse ratings are correct, you will need to have an inline fuse rated above 130 amps. ANL fuses go all the way up to 300 amps I believe, so you should be fine. And no, do not use a circuit breaker. While some people use them and claim they work fine, I would not use them. In an under the hood environment, its been tested that the majority of circuit breakers take too long to open.
For 130 amps, you could get away with using 4 gauge wire, but do not put a fuse on that is more than 130 amps. You always choose your fuse according to wire size first, meaning don't put on a fuse that is too big for the wire, else it is useless. 4 gauge wire can handle up to 125 amps fine, but you will probably not draw that much current anyways, so you will be ok with 4 gauge.

b00gers

Yea that kinda shocked me at first. I am just basing off of what I saw on crutchfield. The Alpine has 2x 20a fuses and the MBQ uses 3x 30a fuses. I have no idea why they are rated so high like that.

I made the comment on #1 based on my experience, but kinda prematurely. I have a G3 Integra and had a 1200watt system. I am not sure of the amperage that was drawn but if reading off the fuses, it was over 120a. I saw the 200 watt and thought, small amp. I saw the 400 watt amp thought 40-60a. So I answered #1 based on that since my alternator is still running ok...shows signs of aging, but still ok. It wasnt until searching to answer #2 that I saw the fuse ratings. h:

I think the Integra alternator puts put a max of 90a. What would happen with a 130a fuse? That kind of current is never going to run through the wires...I am a bit confused on this.

TTT

Yeah, I guess it really depends on the setup. In most cases, you will only draw probably 75% of your total possible current draw, and that is on the really strong notes.

Even though the amplifier only puts out 90 amps, a car battery can put out much more, say upwards of like 500 amps.

b00gers

Thanks. I never knew that.

TTT

No prob, I guess the EE curriculum is actually teaching me something h:

Now what I want to know is why there are still dimming lights, even though there is 500+ amps of current to work with. I'm guessing it is due to a voltage drop, but I'm not quite sure...

Hondaman

From what I've gathered from everyone I've talked to, it is because of voltage drop. :dunno: Sounds logical. They recommend a 1 farad cap to help the system out. How critical is this?

So if I go with say a 100amp main fuse and a 40amp(sub) and 60amp(multi-channel) secondary, would that be too small?
This system will be for sound quality, not quantity.

For more amp specs, Will hit it on the head. Both are on Crutchfield. Here are the links:

MB Quart

Alpine Mono Sub Amp

Thanks again for all your help guys!!

TTT

Yeah, I figured out its a voltage drop. The lights would get enough current, just not enough voltage. As for a cap... usually the can help with very minor light dimming, but if your lights dim alot and for a long period of time, they aren't going to help. They are definitely not going to save an alternator if the current draw is too much either. I would wait until you install everything to see how bad it is, and if its not too bad you could try a cap and it should help some.

As for the fuse sizes... like I said earlier, your fuse size first and foremost depends on wire size. The 'upper limit' to your fuse size depends on how much current the wire can carry. For example, you would NEVER put a 150 amp fuse on 4 gauge wire. 4 gauge can only carry around 125 amps safely, so a 150 amp fuse would be pointless. So, pick your wire size first, according to your current draw, then pick your fuse size. For the sub amp, your maximum draw would be 40 amps. So, the correct wire size would be at least 8 awg. (can safely carry up to 50 amps, so your fuse rating would need to be between 40 amps and 50 amps). For the multichannel amp, your max draw is 50 amps, so you would need to use at least a 6 gauge wire (can safely hold 80 amps). Therefore, your fuse on that wire would need to be between 60 amps and 80 amps. Get the picture?

yeedatoy

dude,there will be no problems with that set-up.just dont listen to your music with your car off.just buy a dual amp kit and go from there.the amplifier instructions will tell you what fuse size you need,and the amp will always have fuses in it.