All,

In response to a question in another thread, and after a very long weekend installing a complete new system to the car, I thought I would pass along a little gem which I was pleased I found.

Getting the power cable through into the cabin is a pain, but I found a way to utilise the existing grommet that holds the rest of the cabling, as follows;

1. Remove the Battery and the clamp/base etc on which it sits. This will leave you with a nice area to work in, as per the following pic (click to blow it up).



2. Remove the glove compartment, via the two clips holding in the hinges.

3. Rotate the grommet holding the power cables anti-clockwise. This will take a little brute force and ignorance, but not too much. Make sure you hold the cables going through it as you do so, they have very little slack so you don't want to risk stretching and breaking something valuable.

A small (5mm-ish) hole will be visible. This is currently sealed inside.

4. Get a HSS drillbit (purely because they are sharper than other types) lube it up with some vaseline, and force it throught that hole. Again, a bit of brute force is required, but you must be careful to not somehow punch into the power cables.

It'll take a bit of wiggling and rotation of the bit, but eventually the rubber seal inside will give way.

5. Get yer power cable, lube up the tip with a tiny dab Vaseline or similar, and just ram in through the hole you have now created. Try not to snigger at the back.

Here's an image of the final product:



I've used 4 AWG guage cable for my power system, as I have two amps to run. I'm not here to recommend what size you use as this will be purely dependant on the power supply required for the amps you have, but I can say that the seal that this then creates with this thickness of cable gives a really tight seal. I am pretty sure a step down to 8 AWG will also be a tight fit, but anything more or less thick will be an issue.

I thought this is an easy and safer method than drilling through the bulkhead or cutting the grommet. The seal is so tight around the cable, I didn't bother using liquid gasket or similar to gum it up, although if you are getting water in that area, you're already in trouble as that's where your battery is (!).

I used 6m of cable to get it through to the boot, and this was just right. Any less than that, and I think you'll be struggling. Do not forget to put a fuse just after the battery terminal. I cannot stress that enough. The fuse should be rated to suit the cable, not the amps. Other FAQ's should resolve this.

Hope this helps! Any questions, just post 'em on this thread.

Great walk through! will be alot of help, thanks

excellent tutorial
i have moved it into the workshop forum

thats how i done mine but i run a 4awg wire plus an 8 awg thrugh the grommet as i was powering my power inverter for my freeview box but took me a little while before i decided to take the battery out but does make it very very easy ro do it

and as for the fuse my mate has a mk4 astra and he put the fuse in the boot so it isnt prtecting anything apart from the amp and to make it worse he feeded the wire through the binner wing so the wire rubs against the door, i did tell him but e wasnt that bothered but spose if it goes up in smoke its 1 less astra lol

The theory is that the Power cable should be as big as possible
as to avoid any losses over a long run, ie Engine bay to Boot (3-4M).
I used a 0AWG Power Cable all the way to the boot, then via a
Fused Distribution Block to the Alpine & JL Audio Amplifiers.

There should be a main inline fuse within the engine bay as close
as practical (within 18")


then go through the bulkead grommet


Pass the Power Cable behind the footwell cover on the left under the
glove box and then under the trim panel that runs along the bottom
of the door frame through to the boot. As I recall there is a small space on
the passenger side behind the rear seat to run the cable through.

My finished install + pictures
HERE

Hope this helps somebody.
Message me if I can help you out.

Wozza - it's a great system, but not everyone has the money to cough up for 0 AWG guage power cable... And most of the time it is not needed anyway.

Allow me to demonstrate.

You should be rating the cable based on the amps the system will pull under normal operation and the length of the cable. You do this by application of simple physics.

Current or Amps is worked out as follows:

Current = Power / Volts (for this tip, the '/' means divide, so you will have to dust off a calculator!).

Power is worked out by taking the maximum RMS value of your amp (not the 'max power' nonsense they use to advertise, all amps should give you a maximum rating in RMS, which is the true value of the amp).

So, if you had a 4 x 100w RMS amp, it's power would be 400w.

Volts is the easy bit, as we have voltmeters on our dashboards. I've always used 12v as rule-of-thumb, but it's generally between 9v and 14v.

So, the current draw is calculated at 400 / 12 = 33.3A. Call it 40A for the sake of argument.

You then take that rating and apply it to this table to determine the size of cable required:

(Source: http://www.talkaudio.co.uk/vbb/showthread.php?t=17899)

Total Length of desired cable
Ampage 4` 7` 10` 13` 16` 19` 22` 28`
0-20 14 12 12 10 10 8 8 8
20-35 12 10 8 8 6 6 6 4
35-50 10 8 8 6 4 4 4 4
50-65 8 8 6 4 4 4 4 2
65-85 6 6 4 4 2 2 2 0
85-105 6 6 4 2 2 2 2 0
105-125 4 4 4 2 0 0 0 0
125-150 2 2 2 0 0 0 0 0

The table is a bit screwed up, but I think it shows it clearly enough.

Note:
1m=3.28`

So, for our example 400w RMS system, total current draw of 40A, with a distance of 6m (from battery to boot in an IS200) or 20 foot, the ideal cable size is 4 AWG, as highlighted in red.

To prove the point, I've got about 600w RMS sytem in total, which calculates to 50A, and I run off a 60A fuse at the battery and it has never blown. You'll only draw the calculated current if you are running all amps, at full power, which would probably leave you deafened anyway!

Don't get me wrong, if you have a monster 1000w RMS system and 3 miles of cable, 0 AWG is usually needed, but for most quality installations, 4 AWG is more than enough. Bearing in mind that quality 0 AWG cable is about £10/m, and 4 AWG is £3/m, you can save yourself £40-50 to spend on better speakers.

Note: I didn't really want to advise this, so I will not take any responsibility for burnt cars because of undersizing based on this guide! I believe they are known as 'Normal Workshop Rules'

Admittedly 0AWG might be excessive for some installs, but is sensible for mine due to
the JL Audio 500/1 Amp has been bench tested to 647 Watts R.M.S at 3ohms, then add
on the Alpine Amp @ 75 Watts R.M.S x 4 (not tested but probably around 50 x4) and I
might still have to uprate the Battery &/or Alternator cos I can still make the lights flicker !!
The JL Audio Sub is rated at 1000 Watts R.M.S. and am sure it could take it, but the mirrors
all start vibrating at high volumes and so does my shirt, and my kidneys take a bit of a
pounding through the seat too, so the smaller (500/1 rather than 1000/1) amp is enough for me.

4AWG is probably enough for most people tho...
As my wife once said, go for the biggest you can get

Hi all I have just put in o awg for my system as it worked out easyer than 4-8 awg. I am only running one amp at the moment but will no doubt will want more as I get use to it. Also I shopped around and found that most retalers are happy to get rid of o awg kits as most people wont spend the dosh on it.
In the local shops around me they sell 4-8 awg for about £45 - 55 and 0 awg for £60-65 I found one that had been sitting in the shop for over a year and after three weeks of haggling they sold it me for £35.00, Cheaper than 4 or 8 awg.
In short shop around and HAGGLE & HAGGLE but when you get the right price HAGGLE some more, limited funds some time is a good thing.

Good luck HAGGLING

A good Haggle never hurt anyone,
0 guage saves replacing with thicker cable later if you upgrade your amps too

thought i would add my bit in too!!

i agree with baldylocks...

as someone who has been doin instals for years now i can honestly say only the biggest systems need 0 gauge..

DJ Wozza: i run a jl 500/1 and a JL 300/4 so thats more power than your JL / alpine set up and 4 gauge does fine. i can also guarantee that my 2 x jl subs are driven harder than the single w7, and would therefore draw more power!

to help with your dimming lights, firstly ensure your earths are all solid and secondly, try earthing the battery to the chassis to create a better earth. Failing that, try disconecting the cap as sometimes they actually make matters worse before you spend any more money then your battery would be the first place to start..

To put things into perspective we had two 15" rockfords in a 500 sl merc rated at nearly 2k rms and stil only neede 2 gauge!

There is no harm in using the 0 gauge but as a workshop tutorial, go with the chart!!

And lets be honest most amps / distribution blocks (including the 1000/1) wont take more the 4 gauge unless u spend silly money!

hope that helps!

DJ Wozza: i run a jl 500/1 and a JL 300/4 so thats more power than your JL / alpine set up and 4 gauge does fine. i can also guarantee that my 2 x jl subs are driven harder than the single w7, and would therefore draw more power!

Obviously they would draw more power bearing in mind I am using the SAME amp
to drive a JL 12W7 rated up to 1000WRMS
The output of the Amp at full power would be the SAME.
Just because you have 2 unamed JL Subs doesent up the max output power of the amp.


Also " thats more power than your JL / alpine set up "

Erm no actually as SAME Sub Amp + the Alpine is rated @ 75 W RMS x 4

...pmsl

I'm not gonna get into a Willy measuring arguement with you, but u aren't stating the truth.

"DJ Wozza: i run a jl 500/1 and a JL 300/4 so thats more power than your JL / alpine set up and 4 gauge does fine. i can also guarantee that my 2 x jl subs are driven harder than the single w7, and would therefore draw more power!

Obviously they would draw more power bearing in mind I am using the SAME amp
to drive a JL 12W7 rated up to 1000WRMS
The output of the Amp at full power would be the SAME.
Just because you have 2 unamed JL Subs doesent up the max output power of the amp."

i will excuse your ignorance and blatant attempt to criticise anybody who might actually know more than you do!!

The fact that two 500w subs running at 2 ohms WILL infact draw more power from the amp. its simple mathematics... i dont feel the need to advertise what subs they are as in fact its a JL built HQ box.



Also " thats more power than your JL / alpine set up "

Erm no actually as SAME Sub Amp + the Alpine is rated @ 75 W RMS x 4

you will find that the alpine amp you mention will only ever give the stated power output when fed a clean 14.4v, which in any car audio system is unlikely to happen, and considering your lights dim definately isnt the case.


...pmsl

I'm not gonna get into a Willy measuring arguement with you, but u aren't stating the truth.

I am in fact stating all truth and dont appreciate being told that im not but i will let it go now as im sure you can see that! You will also see i was trying to offer you some of my advice which im sure if you research is also true.

Please bear in mind that not everybody will throw money at an install and the advice offered in the thread is very sound and covers all bases.

FYI, i have been doing car installs for over 10 years, have been entering in bass comps for many years, so its not info i have recitied from a salesman but lessons learned through research, theory and trial & error.

if you want to get any more info then please get in touch and i will be happy to help...

ur havin a laugh.

FYI I ALSO have had installs in all my cars (though never needed to go into sound off or SPL
competitions) over the last 20 years accept for my last car (Honda Accord Executive)which had a
premium Bose 6 CD sound system including Sub in already. My lights only dim slightly when
I am running the WHOLE whole system flat out with the JL Bass gain controller up more than halfway .

Let's take you points and see whats what.

As I stated above if you took the time to read the whole thread I had previously stated that
0AWG might be excessive for some installs and 4AWG is prob enough for most.

"Admittedly 0AWG might be excessive for some installs, but is sensible for mine due to
the JL Audio 500/1 Amp has been bench tested to 647 Watts R.M.S at 3ohms, then add
on the Alpine Amp @ 75 Watts R.M.S x 4 "

"4AWG is probably enough for most people tho..."

"0 guage saves replacing with thicker cable later if you upgrade your amps too "

With regards to throwing money at my install I bought the 0AWG cable for approx £15
so that ends your arguement there .

Are they JL10W3V2's (d2 or d4)as per your H.O. box pictured (thru ski hatch)on LOC previously ?

Am guessing they are 10's not the JL12W3v2's cos I was going to get the 12" High Output
box but measured it and it wouldn't fit in the IS200's boot between the arches.
I had 2x JL12W3V2's in a double box before my W7 but it only fitted diagonally in the boot,so I had
no boot space at all. I then went to the top of the range 12W7 and had a box specially buit to
the JL Audio specs for a 12W7 .

If they are JL 10W3v2's you are over driving them to danger zone levels as per JL Audios website.
500 Watts RMS ? Strictly danger zone matey . Optimum is 250 WRMS if you care to check.
We'll come back to this cos they aren't actually getting 500 Watts RMS each.
(BTW its a JL Audio H.O. box not HQ)

"The fact that two 500w subs running at 2 ohms WILL infact draw more power from the amp. its simple mathematics... i dont feel the need to advertise what subs they are as in fact its a JL built HQ box."

The JL Audio 500/1 amp is only rated @ 500WRMS irrespective of whatever sub or combination of subs you put on it.
You can add 10 subs to that amp if you have a combination of drivers that in parallel or series adds up to 1.5ohm-4ohm
impedence the Amplifier requires, but it still wont mean you are then getting 500 watts x 10 as per your inferance.
2x 500 Watt subs doesent mean an amp rated at 500 Watts RMS will give you 1000 watts.
"The fact that two 500w subs running at 2 ohms WILL infact draw more power from the amp."
It's not simple mathematics the way you do your maths. That is just incorrect.

read JL's own info on the JL Audio 500/1
"500 W RMS @ 1.5 ohm - 4 ohm (11V-14.5V) "
Whatever combination of subs is applied to the amp in the 1.5 ohm - 4 ohm stated range
the power BETWEEN them will still only total the max output of the amp ie 500 wats !!!!!!

If I did maths the way you do, I gallon of petrol poured from a can will give 2 cars
1 gallon of petrol each if they are parked near each other.
(if you can advise me on how to get 2 gallons out of 1 gallon let me and the rest of LOC know
asap as you will be very popular)


BTW I have magic car wax that at speeds over 100 MPH is worth
100 extra bhp honest Mr.

to be completley honest i think your sarcasm and disregard for anything anybody else says sums it all up..

the whole point of the post was to show people the standard way of putting ice in with decent cabeling without breaking the bank. all you seem to want to do is say how much yours is better.

my point all along is that if it works for you thats fine but let people make there own choices..

again i se no refernce to the advice wether you chose to take it or not but hey thats cool..

oh btw, JL10W3V2 and the JL12W3V2 both fit, and yes it is the 10's and they will accept the power being put through them and have done for 2 years!

so to sum it all up, yes you have an excellent sub amp and sub, would suggest changing the alpine stuff as its nowhere near the quality of the rest and maybe a little overkill on the wiring but you know what, it works and your happy so i am too!!

i hope you enjoy your car and maybe if we meet we shall settle it with a good old sound clash!!

no malice intended towards you , especially a fellow DJ, but please let people make ther own choices..

Mine is not better than anyone else's, but it works for me.



I don't "disregard for anything anybody else says", except when they
don't have the facts right ie 2 subs connected to the same amp as mine
= more power ? (bs detector here pls).

You stated things about throwing money to have a pop at me etc and it just wasnt true .
If you see the post by Astrix above the 0AWG he bought was cheaper than 4AWG !
Mine was bought for £15 !
(oh dear wrong again huh)

"the whole point of the post was to show people the standard way of putting ice in with decent cabeling without breaking the bank"
(erm no wrong again ! it was about routing power cables through the bulkhead.)

The JL12W3V2 HO box doesn't fit if u want it parallel to the back of the car between the arches
cos its approx 2 inches too wide, & I know cos I was going to buy 1, but had to have
a box built instead.
(opps wrong again here)

As for my Alpine stuff,the head unit is one of the best they make for CD playback.
Nuff said.

I'd still love you to answer how you get more power out of
the same amp as me ??

You like to twist and infer things that aren't true.
"but let people make there own choices"
Did I make anyone do or buy anything they didnt want ?
I stated what I had in mine, & told them sound advice where asked for.
You are talking utter rubbish.
Read what I say from above and let's see if I don't let people make their own choices...
Stop making stuff up when u have just got it plain wrong.

from 1st post
"Hope this helps somebody.
Message me if I can help you out. "

2nd post
"Admittedly 0AWG might be excessive for some installs, but is sensible for mine "
(remember the words excessive for some installs and MINE !!)
"4AWG is probably enough for most people tho..."
(again just sound advice)

3rd post
"0 gauge saves replacing with thicker cable later if you upgrade your amps too "
(Sound advice if someone has an eye to maybe upgrading 1 day)






hmm lets agree to disagree I think cos I don't think we will ever see eye to eye on this