U13 install

[wicked]

Hi Car audio gurus,

I've purchased a 4 channel (4 x 125W RMS) to run front components and a sub,
cheap pre amp,
100W RMS 6.5 inch components (Diamond),
an oldish 2 ch amplifier (30W RMS x 2) to run rear speakers,
a oldish Alpine sub (single coil, 4 ohms, 200W RMS),
3 x 5m, 1 x 0.5m RCA cables,
power cable distributor (1 x 4 AWG in and 2x 8 AWG out).

Here's are a few questions:

- Would a 4 AWG power cable from the battery, going through a distributor and splitting into 2x  8 AWG power cable be sufficient to drive my 2 amps?

- Anyone fitted 2x 8 AWG cables through the firewall (Aust U13) without drilling of cutting?

- I intend to install the 2 amps in the boot, how much 8 AWG cable do I need?

- How much speaker cable is required to run it from the amplifier to the front speakers, what size cable should I run?

- Where should I run the power cables and speaker cables through the cabin?

Thanks for taking the time to read this thread. 

[Jono]

- Would a 4 AWG power cable from the battery, going through a distributor and splitting into 2x  8 AWG power cable be sufficient to drive my 2 amps?

Your big amp would draw about 50 amps at full noise, so yes that wiring would be sufficient.

- Anyone fitted 2x 8 AWG cables through the firewall (Aust U13) without drilling of cutting?

Personally never tried, I'm pretty sure Teena's ran through a factory grommet in NIZ013 mk1.

- I intend to install the 2 amps in the boot, how much 8 AWG cable do I need?

Run the 4 gauge back to the boot, then split it up into 8 gauge as close to the amps as is convenient.

- How much speaker cable is required to run it from the amplifier to the front speakers, what size cable should I run?

About 4-5 metres per run of speaker cable. I'd use about 14 gauge cable.

- Where should I run the power cables and speaker cables through the cabin?

Under the carpet along the sills. Run the power cable down one side and the RCAs down the other side.

[P-Unit]

- Anyone fitted 2x 8 AWG cables through the firewall (Aust U13) without drilling of cutting?

Ive run 3*8ga and 1*4ga through the factory grommet, no worries, just use the magic yellow stick from pieces of wood.

- Where should I run the power cables and speaker cables through the cabin?

I ran power in the factory hole up the passenger side of the car, my speakers run straight down the middle, and the rca down the drivers side.

[wicked]

My amplifier manual did specify that the fuse should be installed as closed to the battery as possible. Does that mean that I should have a 4 AWG cable running all the way to the boot and not 2x 8 AWG cables?

How difficult is it to run the cables throught the middle of the car, what is involved?

4 AWG cable is expensive at $8 plus per metres from Jaycar, anywhere I can get it cheaper?

Thanks again. 

[Sticky]

Yes, preferably within 30cm of the battery.

Run one length of 4ga to the boot then split it into 8ga using either a fused distrobution block or similar

Always split your power and RCAs/speaker cabling..you dont want nasty engine noise

[Jono]

Yes, preferably within 30cm of the battery.

I never say this because it implies that having a foot of cable rubbing on metal edges near the battery is ok. Always fit your fuse as close as possible to the battery. And don't let it chafe on any metal edges.

It'd be easier to run the cables under the carpet along the sills.

You can get a wiring kit for about $50-70 from most car audio shops that has almost everything you need: 5m 4ga cable, 2x 5m RCA cables, 15 or so metres of speaker wire, 5m of remote wire and a fuse holder and fuse.

Then all you need is a distribution block and a couple of metres of 8ga cable.

You can get cheap cable from welding suppliers, it isn't all that pretty but it does the job. They measure it in mm², not AWG (American Wire Gauge) so if you ask them for 4 gauge cable you'll probably just get a blank look.

[wicked]

Thanks guys for the heads up. I'll probably do a bit more shopping tomorrow, hopefully I can get everything together and start installation.

[wicked]

Install did not go as smooth as I expected it to be. There are ticking and engine hum noise coming out of my front splits. I've resolved the ticking noise by keeping the RCA as far as possible from the power cable and ECU. Engine hum is still there and it seem louder when the ari conditioning is running. It's not really that loud.

I've had noise suppressor on the power input to my HU and 4CH amp too. I'm using Stinger twisted pair RCAs for the 4 CH amp in the boot and another short RCA from 4CH amp to the 2CH amp. The 2 ch amp seems to run fine. Would running a ground cable from the HU to the 4CH amp ground help (to eliminate ground loop)?

Also, where can I get carpet to match the U13 grey carpet. I'll like do a carpeted MDF to mount the amps.

Thanks guys.

[Jono]

Try some auto trimmers for carpet.

Make sure you've got good grounds on your amps, check them with a multimeter if you can. There should be less than 50mV between the amp terminal and the body of the car when the stereo's cranked up.

Also make sure your head unit is grounded properly.

What kind of head unit do you have?

[wicked]

I have a VDO HU, nothing fancy, just a basic MP3 HU with 4V preouts. I tried running the ground of the HU to the ground of the 2 Amps in the boot, still, there is engine humm when I rev between 2 - 3K, anything above that, my exhaust takes over.

Back to grounding, there should not be any difference in ground potential between the HU and the amp, unless I need to run larger than ground cables for the HU. It has 18AWG ground now.

Strange this is that it is all quiet when the engine is off and the noise seems to be present when air conditioning is on. Hmmm.... 

[Sticky]

How have you grounded both the HU and the amp?

Headunits rarely will induce any noise through the RCAs, unless its a pioneer with a blown earth track, which could be a possiblity with your VDO deck, but id check all other causes first.

[wicked]

Oh, btw, I missed an important clue, the humming is barely audiable till I turn on the air conditioning. Does it implies something? 

[Sticky]

how much more audible is the noise compared with it off?

[P-Unit]

sounds like the alternator may be struggling, it would be helpful if you could tell us voltages at revs with and without electrical circuits active.

[Sticky]

i dont quite see how engine noise could be induced by an altenator that is struggling, and more to the point, unless its shagged, i dont see why it would be struggling in the first place.

[wicked]

how much more audible is the noise compared with it off?

When the air conditioning is off, it's barely audible. With air conditioning turned on, the humm is about 3 to 4 times louder, hence I could hear it clearly. I tried shifting the position of the RCA cables around a bit but it makes no difference.

sounds like the alternator may be struggling, it would be helpful if you could tell us voltages at revs with and without electrical circuits active.

I'll measure it but I'm starting to think how the noise can be picked up by the RCAs since the HU and the amps are using the same ground (eg. no ground loop). I'm starting to suspect that maybe, it's a case of bad grounding of Alternator or compressor or something similar. 

BTW, when I turn the air conditioning on, which modules/components is turned on? Also, do you guys know where it's located? Thanks again. 

[P-Unit]

when i first did my install i had a shagged alternator so my battery wouldnt out out enough power. with the shagged alternator and a/c on the noise was louder.

new alternator = no problems in my install anymore.

[wicked]

when i first did my install i had a shagged alternator so my battery wouldnt out out enough power. with the shagged alternator and a/c on the noise was louder.

new alternator = no problems in my install anymore.

That sounds a lot like my problem except I could hear a very low humm with air conditioning turned off.

Could I check the alternator by putting a multimeter to it? Do I read DC or AC or just ripples on the voltages? How much would it cost to replace the alternator? I want to make sure that I've spending the correct money to fix the problem. Thanks.

[Kranzy]

There is a place on the gold coast that rebuilds alternators for around $150, cheapest ive found, and there work is really good too.

[P-Unit]

i tested my alternator by driving to my mates place, whos dad works as a mechanic and had an alternator testing machine.

[wicked]

I borrowed a 'current clamp' device to measure the current supplied by the alternator, it measures 12.8 amps at idling and 14+ amp when I give the engine a little rev. When I switched on the airconditioning, it went up to 50+ amps. I readup some data from the service manual (Altima U13) and here's what it says:

Hot output current (when 13.5V is applied)

23 amp at 1300 RPM
63 amp at 2500 RPM
77 amp at 5000 RPM

Does it implies that my alternator is suppling too little current? Thanks.

[Kranzy]

Your measuring amps, and referring it to volts. You need to find out what amps the alternator is supposed to be putting out.

[wicked]

Your measuring amps, and referring it to volts. You need to find out what amps the alternator is supposed to be putting out.

This is what the service manual says:

Hot output current (when 13.5V is applied)

23 amp at 1300 RPM
63 amp at 2500 RPM
77 amp at 5000 RPM

It doesn't gel up with my measurement of 14amps at 1300 RPM. Is it an error on my part of is the alternator stuff up already?

Anyone has a alternator tester in Brissy I can borrow for a bit? Thanks.