Racecar wiring

ProZac · Post by **ProZac** » Sun May 06, 2012 7:30 pm

Im not 100% sure I understand what you mean... The main fusible link there is after the battery cut-off switch?

The one I've drawn is the factory starion one that usually clips onto the positive battery terminal and feeds the relay box when the car isnt running, or supplies current to the battery from the alternator when the car is running.

I'm assuming you're having your battery either in the boot, or in the cabin. You could run your main starter cable to the starter motor, and then run a smaller (but still pretty decent cable, something that can handle at least 80 amps) from the starter terminal up to that factory starion main fusible link.

ProZac · Post by **ProZac** » Sun May 06, 2012 7:35 pm

Oh, wait, I think I get your meaning now. I can see what you mean, the way Ive drawn it, yeah, you've got to have a decent cable to the factory fusible link, then another one back to some distribution point inside the cabin for all your relays and stuff.

Yeah, you can definately put in another link directly after your battery to make your own protected distribution point, that'd be a really nice tidy way of doing it :).

So you could have 1 big cable off your battery positive, to your cur-off switch. Then from here, continue with the big cable to your starter, but also attach another cable (say 80 amps of so), with a nice fusible link, that goes to power all your added relays and stuff.

You could then still attach the factory starion main fusible link to your starter motor terminal, and thus your big beefy starter cable, and thus your battery.

I'm shocking with words... Pictures ahoy.

Lunacy · Post by **Lunacy** » Sun May 06, 2012 7:40 pm

ProZac wrote:Im not 100% sure I understand what you mean... The main fusible link there is after the battery cut-off switch?

The one I've drawn is the factory starion one that usually clips onto the positive battery terminal and feeds the relay box when the car isnt running, or supplies current to the battery from the alternator when the car is running.

I'm assuming you're having your battery either in the boot, or in the cabin. You could run your main starter cable to the starter motor, and then run a smaller (but still pretty decent cable, something that can handle at least 80 amps) from the starter terminal up to that factory starion main fusible link.

Haha sorry hard to explain.
Im just wondering where to take the 12v protected distribution source from? Is it just a matter of tapping into the large white wire between the main fusible link and relay box and putting a distribution post there to feed the one fuse box and the IGN relay?
Cheers

ProZac · Post by **ProZac** » Sun May 06, 2012 7:42 pm

ProZac · Post by **ProZac** » Sun May 06, 2012 7:45 pm

Lunacy wrote: Is it just a matter of tapping into the large white wire between the main fusible link and relay box and putting a distribution post there to feed the one fuse box and the IGN relay?
Cheers

Yup, exactly. But I like your idea of making your own point more, would require less cable, and look way tidier I reckon.

Lunacy · Post by **Lunacy** » Sun May 06, 2012 7:50 pm

ProZac wrote:

Gold mate :)
Thats looking like the best way to do it i think.
Off shopping in the morn for those diode relays for fuel pumps and fans, and for the fuse holders. Wil get auto sparky to do me up another fusible link at the same time.
Managed to get halfway through building a centre console to house all the switches and power window controls plus starter button today, so once thats sorted can get into wiring it all up :)
Thanks again for the help mate

ProZac · Post by **ProZac** » Sun May 06, 2012 7:51 pm

And if you were being really pedantic, you should tap into that white wire underneath the relay box, on the far side of the ammeter signal wires.

The way our ammeters work is kinda smart, but also really dumb. Our main wire going to the battery (not the starter one, the one for all the other circuits) is actually really long, but is bunched up in a big roll underneath the relay box. The signal wires for the ammeter tap into this roll at either end, providing another, shorter, path for some current to flow, this making the ammeter deflect.

the ammeter deflects downwards when current flows through the big loop from the battery to the relay box, and upwards when it flows from the alternator back into the battery.

Tapping into that white wire at the main fusible link will mean that when your car is is off, but your circuits are powered up, the ammeter WONT read them. When your car is running, and the alternator is supplying your circuits, the ammeter WILL read them, and deflect upwards too much.

Just like how I've wired in my electric radiator fan, but I'm a dummy ;).

Lunacy · Post by **Lunacy** » Sun May 06, 2012 7:53 pm

Oh yeah, then its just wire size and fuse sizings i need to figure.
Im guessing with wire its better to be bigger rather than too small, but is the fuse sizing going to be a bit of trial and error?

ProZac · Post by **ProZac** » Sun May 06, 2012 7:53 pm

I really hope your car doesn't burst into flames. I'll feel quite bad if it does.

ProZac · Post by **ProZac** » Sun May 06, 2012 7:56 pm

Fuses for the power side of things will usually come with whatever is being powered. Electric radiator fans usually come with 10 or 15 amp fuses for example. Your ECU manual should have a listing somewhere for what size fuse to use.

For the fuses on the switching side of things, you need to make sure they're quite a bit smaller than the amount of current the wires can handle. The switching side of relays is pretty low current however, i remember reading somewhere that its around the 100mA range, so I'd say you'd be fine with 2.5A fuses here. That'll make sure that if you have any wiring shorts, the fuse will pop far before the wires burn up.

Lunacy · Post by **Lunacy** » Sun May 06, 2012 7:58 pm

ProZac wrote:I really hope your car doesn't burst into flames. I'll feel quite bad if it does.

Haha don't worry il be testing every circuit before i fire everything up so should be fine. What sort of size cable and fusible link do you think itd need between the kill switch and the distribution block for fuse holders/IGN relay?
I wouldn't have thought itd need to be huge

ProZac · Post by **ProZac** » Sun May 06, 2012 8:03 pm

Factory cars run something like 80-100 amps, but that's for EVERYTHING in the car (except starting current), yours is just for the circuits you've added. I'd start with a 60, and I reckon that'll be fine?

Fans typically draw a few amps, fuel pumps a few too, the ignition system a few more. ECU and the rest of it will be bugger all though.

Lunacy · Post by **Lunacy** » Tue May 08, 2012 7:17 pm

Was just chatting to Jase, and he has a 100 amp circuit breaker mounted in his positive battery cable right next to the battery, and no main fusible link (the one off the positive battery terminal). Would this suffice to cover the line to my own distribution block as well? Or would i still need that line to be fused? Can only find these type of fusible links at the auto sparkys, so may well just put a 60 amp one in that line if needed.
http://www.narva.co.nz/products/browse/female

Lunacy · Post by **Lunacy** » Tue May 08, 2012 8:26 pm

Also is there a better way than this to supply one entire side of the fusebox with +12v? As this is powering fuel pumps, fans, ecu, heater etc wondering if i'm going to get a voltage drop doing it this way.

ProZac · Post by **ProZac** » Wed May 09, 2012 11:43 am

Hmmmm, I'm at a bit of a loss as to a better way to wire up the side of the fuse box. There isn't something out there that has some sort of bus-bar, like factory fuse-boxes? I havent actually had a good look at what is available. I have bought some bits and pieces from http://www.vehicle-wiring-products.eu/V ... mepage.php, and found them to be pretty good to deal with.

For only having one fusible link/circuit break would work, as the big run to the front of the car is still protected.

Austarion

Racecar wiring

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