MikedaPimp

I went to Best Buy after work today and talked to one of their installation guys. He said running 4ga to each amp would do fine, but if im worried about it run a 2ga and split and run 4 ga to each amp. The manual only mentions 4ga. Also, he said that a 100amp fuse would be the one to use on the power wire. This sounded a little funny to me. He also said 12ga would be good for all the speaker wires. I didn't ask him where to run the power wire.

Also I read the manual, and found out I do connect the subs wires to the outside + and - outputs for the bridged/mono mode.

Also, I decided to go with the 8200. Why did you pick the P720 over the P8200R? They seem very similar to me. Also will I have to modify the cage/enclosure/dash to accomodate the 8200?

Gracias.<p>~Mike
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Mark P

When your amp says stuff about 4ga, it is talking about the minimum size wire. If you are running two amps, you can either run two separate 4ga wires, or run one bigger wire and split it into two separate 4ga wires back by the amps. The "bigger" wire should have a cross sectional area equal to or greater than the sum of the cross secional areas of two 4ga wires. Think again of the water analogy. IF the bigger wire is not much bigger than the 4ga, it can not supply enough current (think water) to flow in the 2 4ga wires. That is to say, your weak link would be in the bigger wire if it was not big enough. Is 2ga big enough to be split into 2 4ga wires? I don't know for sure, but I'd think it would be.

If you use a single wire with a single fuse, you have to use a larger fuse (they mentioned 100A). This causes less protection on your wiring. Before, with two separate wires, you had ~50A fuses. Thus if your wiring shorted out, it would have to draw >50A before the fuse blew. Now, it will take >100A before it blows.

I'm not saying which way you should wire it - just pointing out the differences. Perhaps they are so subtle, that it won't matter, but again they are just the differences.

Also, the typical inline fuse that you would use with a 4ga or 8ga wire has a max value of 60A. If you need a 100A fuse, you'll need either a circuit breaker or perhaps some flat blade fuses go that high (not sure). Just another difference.

Also consider if it will be easier to run 2 4ga vs 1 2ga. Some newer wiring (RF?) that is that large is not completely round (kinda flat/oval) to help routing it under carpet, etc.

12ga is what I am running to all speakers. Probably overkill on the components, and adequate on the subs. Actually, probably usefull on the front door subs as the distances get quite long at 20+ feet and you'd like as much copper as you can over that distance.


Hey, cool I guessed right on the mono sub connection - that seems to be the "norm" of the ones I've played with.

I don't have the P720 (did you mean P7200?). I have a Pioneer unit from 3 years ago. While mine is a "7" (DEH-P735) series, it has the features of the current 8200, with respect to 3 sets of RCAs, remote, etc. Hmm, don't think I've taken a pic of my remote yet - will do one of these days. However, I'm not even using my 3 sets of RCA outs because I have the separate EQ. So, I have one set of RCAs going to the EQ, then 3 sets going from the EQ to my amp. I find it hard to believe there is much difference in size in those two decks. Let me check it out....<p>Mark P

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MikedaPimp

you're saying to run both wires straight from the battery, two 2 fuses, and then run the two spearate wires all the way back, to each amp.. Not splitting one 4ga into two right? And then put a 50A fuse on each wire?

They did mention needing a circuit breaker by the way, if i used a 100A fuse. And a stiffening cap, but I got one of those.

Ok ok, I think it would be a lot easier to do it this way - if this was *your* car, how would *you* do it, because when you leave choices up to me I have no clue. Would you run two 4ga, or split a 2ga into two 4ga? Or split a 1/0 ga into two 4ga? Just tell me what to do, I'll figure the other stuff out on my own. I don't want to mess up something as important/simple as just getting power to the amps.

See this whole wiring thing gets complicated. Well probably not for you, you're probably sitting there thinking "Geez, Mike's a moron....ok how can I put this so that a dumbass will understand it..." Lol.

As for the 8200, I'll look again for measurements but I didn't find any. If you want you can check for yourself, I went to Crutchfield, typed in 199 Audi A4 Non-Bose, and it listed everything that would fit my car. The P8200 was not on the list. I would imagine that they would all be the same size, but it may differ. Thanx again.

PS Why won't this sig pic load? I see everyone elses but mine.<p>~Mike
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Mark P

If each amp needs a 4ga, you can not take one 4ga from the battery and split it to two 4ga to each amp and satisfy the requrement of the amp.

Some of my choices may be based on what dist blocks I could find available. Ideally, I would take a (less than 16") 2ga wire, connect it to the battery at one end and connect the other end to a dist block that has a single 2ga openning on one side and two 4ga opennings on the other. If such a dist block exists that has two fuse holders built it, I would get that one. If not, I would then put a fuse holder on each of the 4ga wires ~6" (or wherever is convenient) after the dist block.

I feel more comfortable about drilling (or finding) holes in the firewall to get two 4ga through, as well as making it easier to run throughout the car. And you still have more protection (smaller fuses) on the wiring.

That's what *I* would do, though I'd have to seek out that dist block, which should be available.

Also, you may want to upgrade the connection to your battery. To do this though, you would have to cut the old connector off and get a new one to accomidate the stock wires plus your new wiring.

a note: depending on what connectors are available for 2ga wire, it may be easier to bypass the whole dist block and just run the 4ga wires straight to the battery with a fuse holder on each. If you upgrade that battery connector thingy, this may be an easier solution that getting one to accept 2ga. I haven't looked, so I'm not sure what's available.

I know it's complicated - I still learn new stuff every day. There was *NO WAY* I was ever thinking about wiring my first amp, back when I was 16. My wiring adventures kinda peaked about 5 years back when I had ~20 relays operating all sorts of things throughout my car. Oh, then there were all of the switches controlling all of the relays. A wiring nightmare to some, but I thought it was cool. I had a button to turn on "ACC Power" in my car without the key so I could listen to my stereo while hanging out and not be concerned about leaving my keys in the ignition. One small side effect of that was that if I started the car, pushed the button, then turned off the car, the car would still be running. The electical system thought the key was still in as I was providing ACC Power. However, the mechanical system knew the key was removed, so the steering wheel would lock. In the winter at work, I would go out, drive my car up near the building, do the above (turning my wheels to the curb) and lock the door with the key. My car would be warming up, melting snow/ice and yet the doors would be locked, no key in the ignition, and the steering wheel would be locked to one side. In fact, with my dark tint, people probably just assumed someone was in the car.

Whoa, a little straying off topic!<p>Mark P

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MikedaPimp

Alright well the real reason I want to install it all myself is to know that everything was done right. I'm kind of a perfectionist. I want to be able to know where everything is in case I need to go in and fix something, or upgrade, etc. I always build things myself to understand how they work. Also, I really don't want to dish out the $400+ for some strange guy to do it and hope he does a good job.

I figure building the sub box will be easy, I always go out in the garage and just start building stuff, tree house when I was little, birdhouses, catapults (hey those things are cool!)cat house currently, etc etc.

The wiring is pretty new to me. I understand the basics of it. It's not even that hard to just get a distribution block and some fuses. I just want to make sure it's all correct before I do the whole install, then turn on the ignition and hope for the best. Actually that's another thing - did you test everything beforehand to make sure it worked? Or did you just install it all and pray?

Since you know about relays, what kind of one would I need to run two 12V fans for my amps? What wire would I tap in to? Thx.<p>~Mike
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MikedaPimp

I looked all around for a fused distribution block that has one 2ga input and two 4ga outputs. No one has any. In fact, no one carries any that splits a 2ga into 4ga. The closest thing was a 1/0 ga splitting into two 4ga. Also, no one has regular distribution blocks that split a 2ga into two 4ga. So I'm gonna go with the 1/0ga splitting into two 4 ga. 50A fuses on those right?<p>~Mike
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audiquai

Why don't you just run either 2 gauge or 1/0 from the battery to your amp location, then use a fused distribution block with 50 amp fuses to split into two 4 gauge wires. Makes for a cool display, too.<p>99.5 A4 1.8TQMS APR Stage 1

audiquai

<p>99.5 A4 1.8TQMS APR Stage 1

MikedaPimp

Except it won't work. The fuses have to be within 18" of the battery, unless there is something special that happens with the fused dist. block. I couldn't find anyone that sells a dist. block that splits a 2ga into two 4 ga, read post below. Thx.<p>~Mike
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Mark P

This refers to a typical 30A automotive aftermarket relay...

Basic function is that it is like a normal switch, but instead of manually flipping it, you provide a voltage to make it switch. Some people wonder if you have to provide that voltage, you probably need a switch or something like that anyway, so why *also* use a relay. The answer there is that the signal that you use to switch the relay is different from the power that is provided to the device (fan, in this case). So therefore, if you need more current that you can get from the orig switch, you can do so by using a relay. A typical automotive aftermarket relay draws only 0.5 amps from the switching source, yet can pass ~30 amps to the device that is connected.

Also, some relays have 4 pins and operate like a light switch where the output of the switch is "normally open" (off). Some relays have 5 pins where, the fifth is the "normally closed" (on) position. As an example. this normally closed position is used when implementing a starter disable function. *Normally* you want the switch to be in the closed (on) position, so you can start the car. When you have the alarm set, you want this relay to be in the open position so the car can't start, and thus you have to supply the voltage (output from the alarm) to make this relay switch.

So for your 5 pins, one is the input to the switch, two are the two possible outputs that the input can go to. (where in the 4pin relays, there is no pin at the "normally closed" output). The other two pins are where you connect power and ground when you want to make the relay switch.

I'm not positive, but I recall the pin #s to be as follows:
Pins: 85, 86, 87, 87A, 30

85 & 86 are the power and ground connections to make the relay switch. Have one connected and the other going through a switch or whatever is applicable in your situation. 85&85 can be interchanged. So, for you, connect 86 to ground and 85 to the remote turn on lead that goes from your stereo to the amps.

30 is the input
87A is the normally closed output
87 is the normally open output

30 goes to power (+12V)
87 goes to your fan 12V input.
87A does not get connected (see why some relays don't even have this pin)
connect the ground side of the fans to ground<p>Mark P

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