Hi all,

I just have a few questions about various audio/visual equipment in my car.

Q1. Is 8 gauge (it was all ready installed in my car) big enough to run the following:

1 X jaycar 4X100rms amp (http://jaycar.com.au/productView.asp?ID=AA0426&keywords=car+amp&form=KEYWORD)
1x jaycar splits (http://jaycar.com.au/productView.asp?ID=CS2338&keywords=component&form=KEYWORD)
1 X 6x9s (http://jaycar.com.au/productView.asp?ID=CS2378&keywords=6+x+9&form=KEYWORD)
In the next couple of weeks I will be running a standard car pc (intel motherboard atom 330 1.6ghz, 320g hard drive etc, 2gb ram, m2-atx power supply etc.) and 7" lilliput touch screen.

Q2. What size fuse should I be using, I noticed my amp has 3x30 amp fuses, so should I got for a 100amp fuse and this should also be enough for the car pc, or does it not work like that and I only need something like a 50 amp (this is what was all ready installed with the car)?

Q3. Also I am using this speaker wire (http://www.aerpro.com.au/list.php?pcode=AP940/12&cat_name=power+and+speaker+cables&cat_no=06&product_name=Speaker+cable,+12+Metres+of+2+x+40/0.12mm,+Blister+Packed&cat_sno=135) to hook up my speakers, it doesn't say what gauge it is but it should be enough shouldn't it?

Q4. When installing my car pc, can I just use a power distribution block and run power to the pc from the amp 8 gauge wire? Or should I run another smaller cable from the battery. Any suggestions on what size cable?

Last Question
Q5. What is the best way to go about sound from a car pc, just use onboard sound and run rca leads, or should I invest in a usb sound card? Will it still sound as good or better then a reasonable head unit with either of these options?

Sorry about all the questions, I did do a search and found some semi decent information but not exactly what I wanted. Hopefully some of you can help me answer these questions.

Thanks a lot.

Q1 - Yes an 8AWG cable is enough for that amp.

I'de run a 4AWG to a fused distribution block, and split the 8AWG there, and run another cable to the car PC.

Q2 - the fuse is there to protect the wire. I generally choose a fuse size as close to, if not a touch lower than the maximum current draw of the amp (providing the wire is not undersized). Say the current draw of the amp is 60amps, I will use a 50amp fuse.

Main reason for this is, well, the amp will never pull 60amps for very long due to the way amps work.

Secondly, a fuse takes time to blow - up to 5minutes at 110% current draw. The smaller the fuse, the quicker it will blow - the more likely it is to protect that wire.

My 0AWG cable can hold 330amps, there is no way im putting a 300amp fuse in there - current one is 200amps.

Q3 - that cable is 26AWG, I'de prefer something in the region of 16-20AWG personally. Cheap 16AWG is only $3/m.

Q4 - refer to Q1

Q5 - read Mitchello's car pc thread.

Thanks for the info, dam so I might have to go and re-wire my car with slightly thicker wire, not looking forward to fitting thicker wire through that dam plastic snorkel thing between the front doors.

I am still confused about my amp and the fuse though. I have read that I should add up the fuses on the amp, which is 3X30amps so a 90 amp fuse. I have also read that I can work out the fuse size I need by adding up the total rms (in my case 4x130rms = 520) than times it by 2 (1040) and then divide it by 13.8, which equals 75amp fuse. Which method is more accurate?

Cheers.

Look it all depends on where the car PC is. If its easier, just run another wire from the battery to the carpc. Its possibly less hassle.

Which method is more accurate? the one that stops your car from burning to the ground lol

For some unbiased information - http://bcae1.com/fuses.htm

I would run a 4AWG for a few reasons:
1. Lower voltage drop
2. System flexibility - if you choose to add another amp later on, you can and the 'infrastructure' is already inplace.
3. Its not that expensive in reality.

Run this through a fused distribution block.

Find your amp manual, and find out the maximum current draw. Pick a fuse as closely rated to this as you can, as I said, I either pick a fuse at the same current rating, or 10-15% below.

With your car PC, say it draws 10amps, and you run a 10AWG wire (which should support around 30amps). I would run a 15amp fuse. The reason this fuse I would not have at say 5amps, is that your car PC will be a constant load, not oscilating like an amp.

Q1. Is 8 gauge (it was all ready installed in my car) big enough to run the following:

its big enough but id run a 4ga, even if you are just running 4ga to amp, the jaycar takes a 4ga wire. i found that as soon as i upgraded to 4ga from 8ga i got better and more sound out of the 4x100RMS amp.

Q2. What size fuse should I be using, I noticed my amp has 3x30 amp fuses, so should I got for a 100amp fuse and this should also be enough for the car pc, or does it not work like that and I only need something like a 50 amp (this is what was all ready installed with the car)?

you can use 80-90amp fuse, thats fine. id definitely go bigger than 50 though

Q3. Also I am using this speaker wire (http://www.aerpro.com.au/list.php?pcode=AP940/12&cat_name=power+and+speaker+cables&cat_no=06&product_name=Speaker+cable,+12+Metres+of+2+x+40/0.12mm,+Blister+Packed&cat_sno=135) to hook up my speakers, it doesn't say what gauge it is but it should be enough shouldn't it?

14-16GA for speaker wire is generally what people use. im running 14ga which i purchased from jaycar for about $2.50/metre. many thinner strands of wire is better than less thicker strands within the wire coating. this really depends on the power handling of your speakers as well. im running speakers rated at about 80WRMS, so 14GA really brings them to life..

what you can do for installation is use your current wire and attach the new wire to the current wiring, and pull it through, insulation tape is fine to attach

Q4. When installing my car pc, can I just use a power distribution block and run power to the pc from the amp 8 gauge wire? Or should I run another smaller cable from the battery. Any suggestions on what size cable?

not sure as ive never dealt with car pcs

Speaking of car pc's mine just arrived in the mail just this minute (I still have to build it though and purchase a screen). I will have my car pc under the passenger seat.

Thank you for the input everyone.

Good idea about using the previous wire to drag through the new wire, should make it a lot easier.

I am off to jaycar to get some speaker wire, power cable and a fuse.

Thanks.

hi

due to pc's being fairly power delicate, i;d run a separate wire just to be sure. As the amps have there own fuse sweet but does the pc? if not the larger fuses may not blow if the pc has a problem. You can still take power from the amp wire but use a lower fuse to it. hope this makes sense?

as with all pc's the mobo will put out ok sound, try it. if no good try the usb sound card but beware, most usb sound cards are only the same as on board or worse. unless you spend a good wad of cash.

what software is the car pc running?

many thinner strands of wire is better than less thicker strands within the wire coating.

Umm....

What?

How is it better?


you can use 80-90amp fuse, thats fine. id definitely go bigger than 50 though

Why again?

If the amp draws a theoretical 50amps (which is not a constant 50 amps...but anyway), and you throw in a 80-90amp fuse (which, for an 8AWG cable running from battery to boot is already too large, but for the sake of this discussion lets say the cable can support 90amps)

Then the current running through the fuse will need to reach 180amps for up to 5 minutes before it blows. At this stage, your wire is burning your car down.

http://www.mj-garage.com/pics/Proper%20AWG.bmp

http://www.mj-garage.com/pics/Proper%20Fuse%20Size.bmp

http://www.mj-garage.com/pics/Proper%20Battery%20Size.bmp

http://www.mj-garage.com/pics/Proper%20Alternator%20Size.bmp

Nice call ERS

very handy info

i have a duel batt setup and amps aswell.

the main fuse due to convenience and availability i used a 40 amp.(Amps are rated at 40amp each max draw.) this will run all amps as loud as i can stand and hasn't blown. (may stop some current but i've tried with a bigger or no fuse and system still sound the same.)

a 30 amp will blow in mine every time, but a 40amp is sweet. . my set up is a bit difficult to explain but i always will go a lower fuse if needed.

this stuff does get complicated but as long as the main components have a correct fuse for there current draw that's fine.

As per the main power wire , same applies but it will blow very easy even with a 100amp fuse if its shorted and will blow other smaller fuses inline to items first depending on were the short is.. hence you know theirs a problem.

This is not a how to but might help.....at the end of the day wire it correct and use covers or wire shield in places it might be prone to rub through and you wont have to rely on fuses as much as there a last resort for safety.

Just for a laugh my first stereo install by a mate used crap solid fence type wire with a plastic coating and no fuse.

pulled in the driveway and said to myself "man that smells!" looked at the lower door scuff plate and the wire was melting into it and was glowing red..lol
not really funny at the time but that's what can happen.

learnt my lesson that day.:nuts: what was i thinking..or my mate that is.

Umm....

What?

How is it better?


It's to do with physics, when moving electrons like to flow around the outside of the wire and not through the middle of it. More smaller strands means more surface area means (slightly) less resistance.

Will try and find a link....


As for the audio, a USB soundcard will probably sound better, as well as giving you more control/channels on the higher spec cards.

It's to do with physics, when moving electrons like to flow around the outside of the wire and not through the middle of it. More smaller strands means more surface area means (slightly) less resistance.

sweet yes that's the one.....


if you go usb sound use a breakout part....eg not in a stick.

you will find on board is fine, but if you must use a plug in, use a box not a STICK. there crap!

that's my call as Ive used them in the past but maybe wrong with newer stuff.

also I've read new articles about the sticks from a good source and there only average at best.

A break out box will give you all the plugs etc and supply better sound.

any way that's my opinion but good luck with it.

cheers.

It's to do with physics, when moving electrons like to flow around the outside of the wire and not through the middle of it. More smaller strands means more surface area means (slightly) less resistance.

Will try and find a link....

Yes I know that, im still asking how its better (and not looking for an arguement).

Slightly less resistance, as in 20% less? 10% less? 5% less? While it is measureable with a multimeter, you wont hear the difference unless you do back to back tests in comparison to chicken fencing wire.

Using the right gauge cable to me is a lot more important.

As long as the cross sectional diameter is correct (if not oversized) and the lengths are kept as short as possible - the difference between a cable with say 40 strands, and one with 60, 80 or 100 is in-audiable. Even over longer distances, I highly doubt anyone can pick the difference.

Yes I know that, im still asking how its better (and not looking for an arguement).

Slightly less resistance, as in 20% less? 10% less? 5% less? While it is measureable with a multimeter, you wont hear the difference unless you do back to back tests in comparison to chicken fencing wire.

Using the right gauge cable to me is a lot more important.

As long as the cross sectional diameter is correct (if not oversized) and the lengths are kept as short as possible - the difference between a cable with say 40 strands, and one with 60, 80 or 100 is in-audiable. Even over longer distances, I highly doubt anyone can pick the difference.

probably right.

4ga is a good idea.

Main fuse is generally the total of all the fuses on your amp combined plus 10% ( i.e. a total of 70A on your amps, use an 80A fuse ) as the fuses on the amp themselves will protect the amp from damage, the main fuse is only there for major major shorts. This is why most amps have 3 way protection. :D

I just installed 4 ga wire in my car and upgraded all the speaker wire, so I am at the stage of installing the amp now. I am thinking of taking out the spare tyre and putting it in there. If i travel any where, which is unlikely for a long while, I will just put the spare tyre back in and place the amp elsewhere.

After the amp I will move on to the car pc. I think I might just run 10 gauge power wire directly from the battery and fuse it. I will update this thread when I get around to installing the pc as I am sure I will have a few more questions to be answered.

Cheers.

Just a word of warning - not sure about QLD, but im pretty certain in NSW that if your car comes fitted with a spare tyre, it is illegal to travel without one - its a defect.

As above is it illegal not to have your spare. It's not hard to build an amp rack inside the spare wheel if your amp fits. If not, look at mounting it on the rear of the back seat, under the passenger seat, on the rear side panel of the boot etc....

I didn't know it was illegal. Guess I will leave the tyre in :cry:. My amp is too big to fit in the tyre. I will see how I go with fitting it either on the back of the seat, or on the side wall.

Thanks for the info.

In vic its legal not to have a spare. But if you do have one it must be usable eg road worthy

ive got a second battery and the sub in the wheel well.

I didn't know it was illegal. Guess I will leave the tyre in :cry:. My amp is too big to fit in the tyre. I will see how I go with fitting it either on the back of the seat, or on the side wall.

Thanks for the info.

Yeah your in QLD so it is probably ok. Ask your Road Authority about it :D

yo fork where did you decide to put your crossover? i cant really find anywhere close enough to the top of the dash without interfering with the airbags... any ideas guys?

also we're looking for a hole to get the power cable from the battery to the amp and can't find one, any suggestions?

What kind of car do you have?

Regardless of which one if it is Auto you can put it through near the pedals.

If it is a 3rd gen, there is a grommet on the passenger side that pops out just above the bottom of the glove box. You will see the coolant fluid and transmittion fluid pipes just above it.

second gen drivers side there the aceel cable goes through there is room in the grommet

lifesaver! straight through that grommet :D also tell me is it possible to get the speaker wire through that little plastic thing in the doors? 16ga is being very hard :( other than that we're having a grand time!

Ha fair enough. I hate doing big installs, you get all excited and about half way through you just get tired.

You will need either packing tape ( that blue stuff that supports boxes ) or a coat hanger.

Under the black bit of the grommet that connects to door there is a white plasic holder. You can get both of these off with a smallish flat head screw driver. Then once off put the tape or coat hanger into the hole to the cabin. It will poke out somewhere and attach the speaker wire to it and pull it back through ( very fiddly ). Work it through the grommet bit the same way and into the door.

To re-attach just pull the black protective bit over the white plastic first, then clip back in. :D

Yep, I put the power cable through the grommet thing. Just use a coat hanger, unwind so it is straight, then just bend it in half (if that makes sense, if not I will take photo's for you). It took me a few times to poke through and be able to see it from inside the car, but eventually i got it and just taped the power cable to the coat hanger and pulled it through.

It's the same thing for the doors, it is a tight squeeze with thick wire but it is quite possible.

I just left my crossovers in the side door. I just placed them laying down nice and snug at the bottom inside the door. The windows don't hit them and they are fairly secure, I am a bit worried that water might get down there though, so I am also open to suggestions for placement of the crossovers.

I have built my mount in the tyre well, so tomorrow arvo after I finish work all I have to do is screw down the amp and connect her up :happy:.

we decided to put the crossovers down in the footwell, just mounted with some double sided tape stuff, we resoldered wire to the tweeters and have mounted them on the dash! should be finished early tomorrow afternoon :D

the 6x9s are too big for the rear door so we need to use a spacer (or something with a similar effect). all the wiring is in place under carpet and kick panels, the headunit is connected, all we need to do now is finish the wiring into the drivers door, mount the amp, fit the rear speakers, connect it to the battery and voila!

if the speaker is in the door! mount it there then run the cable to the tweeter you can mount it on the inside of door or on the outside if you want to show it off.?

very simple but have a go.

have you done the tweeters yet?

you may have to make some mounting points but that's the way it goes with upgrades on a small budget.

all the best.

hey man i wanted the tweeters to sit on the dash in place of those little pods where the verada 4" speakers usually are, all done :D thanks for the tip, if i dont like it where it is i can always move it

also this wednesday at the meet it'd be great if someone could help me make my console a bit more "fitted" if you get what im saying.. i can never seem to get all the clips to go in

twlvlksjstlky, did you end up making mdf mounts for your speakers? I bought a jigsaw for $35 and bunnings today and worked a charm for cutting my amp mount for the boot from a slab of MDF. Just wondering how you went if you made mdf mounts cus I might do it next weekend.

Also, how did you get your tweeters in the 4" hole on the dash, did you cut a hole in the plastic cap thing, or did you just screw them in on top or something.

I haven't decided where I am putting my tweeters yet, might just use the double sided tape provided and stick it on the pillars.

Cheers.

twlvlksjstlky, did you end up making mdf mounts for your speakers? I bought a jigsaw for $35 and bunnings today and worked a charm for cutting my amp mount for the boot from a slab of MDF. Just wondering how you went if you made mdf mounts cus I might do it next weekend.

Also, how did you get your tweeters in the 4" hole on the dash, did you cut a hole in the plastic cap thing, or did you just screw them in on top or something.

I haven't decided where I am putting my tweeters yet, might just use the double sided tape provided and stick it on the pillars.

Cheers.

nah i didn't end up doing the MDF mounts, decided just to screw the speakers into the original plastic mount... sorry im of no help there

with the tweeters, i drilled a hole in the little 4" covers, fed the wire through there and sat the tweeters on top of the covers... looks pretty cool actually, just used some double sided mounting tape to sit them there, ill take some pics tomorrow when its all finished!

Ok, I might do the same for my tweeters but I have a dash mat so i might have to cut a little hole in that, which I don't mind doing. I will just have a play around with them with some blue tack sticking them around at various places and see what sounds best first.

Cheers

Might be a bit late but most tweeter mounting kits come with a bracket double L shape bracket. They are acutally a 4inch adapter bracket :D