Racecar wiring

Lunacy · Post by **Lunacy** » Wed May 02, 2012 8:54 pm

Ok so am going to use this as a check thread to make sure my chain of thought is right for wiring up the following:

Battery Kill Switch
Starter button
Toggle switches, 8 way fuse block and relays for each circuit
EMS Stinger ECU
Bosch 044 Fuel Pump
VL commodore fuel pump
2 x 12" aftermarket radiator fans

I WON'T be using any of the following:
Factory key ignition switch
Factory heater
Factory radiator fans

The circuits i'm going to wire are as follows:

Ignition
ECU
2 x Fuel pumps
2 x Fans
Heater fans

Main Battery Circuit:
Battery Negative to Ground
Battery Positive - Kill Switch - Starter Motor - Alternator - Fusible Links

Kill Switch - 8 circuit fuse box - toggle switches

Ignition Circuit:
Fuse box - IGN toggle switch - Start Button - Relay - Starter Motor Solenoid changed thanks Zac

ECU Circuit:
Fuse box - ECU toggle switch - Relay - ECU 12v input plus injectors, coils, cas and wideband o2 sensor

Fuel Pump Circuit (1 circuit for each pump):
Aux OP on ECU - Relay - Positive terminal on pump
(Where can i install a toggle switch and fuse here?)

Fan Circuit:
Aux OP on ECU - Relay - Positive terminal on fans
(Where can i instll a toggle switch and fuse here?)

Heater Fans:
Fuse box - Heater toggle switch - Relay - Positive terminal on fan heaters

Sorry its long and drawn out, and poss hard to understand. Im hopeless at drawing so writing it is easier for me.
Any criticism/changes/ideas appreciated, also if anyone knows sizes of fuses i should use, or wire size for each circuit that'd be great.
I'll update this as i figure it all out, so hopefully will be useful to others.

FST4RD · Post by **FST4RD** » Thu May 03, 2012 2:28 am

I'll be keeping an eye on this thread.
Was thinking about the starter button, and not using the starter ignition at all, but for a car that i still want to use for Sunday drives i wasn't sure about the law here. Probably have to have a key for a road car?

kiwieurospec · Post by **kiwieurospec** » Thu May 03, 2012 6:23 am

No heaps of cars have push button start now, old cars have it or a pull leaver. No dramas there.
Hybrids piss me off as you keep starting/stopping them because the engine doesn't start until its needed.

FST4RD · Post by **FST4RD** » Thu May 03, 2012 6:56 am

I ment get rid of the key barrel all together like it sounds like Bryce is going to do. Was going to just have a key for drivers door and boot (Im welding up the passengers key barrel hole).
Was also going to get solex locks.

ProZac · Post by **ProZac** » Thu May 03, 2012 7:55 pm

I don't see any legal issues with not having a key barrel? Your insurance company might not like it though.

Lunacy · Post by **Lunacy** » Thu May 03, 2012 8:44 pm

Yeah im undecided as to whether il leave it on just for the steering lock or ditch it totally. As mine is solely a track/race car im not fussed on it really.
Anyways... any flaws in my wiring plans????

ProZac · Post by **ProZac** » Thu May 03, 2012 10:43 pm

Lunacy wrote:Battery Positive - Kill Switch - Starter Motor - Alternator - Fusible Links

you only need to take it from the starter to the main fusible link that protects the relay box by the passengers side headlight. From here a big white wire travels through the loom just in front of the radiator, through another fusible link to the alternator. This same wire, on the alternator side of the fusible link branches off to two more large white wires that connect to the fuse box inside the car via another 3 fusible links. Gah, fusible links everywhere!

Lunacy wrote:Fuse box - IGN toggle switch - Relay - Start Button - Starter Motor Solenoid

I can see what you're achieving here, that starter button will only have an effect if the IGN toggle switch is switched on. However, the relay here seems to be in the wrong place, I'd have the IGN toggle switch feed to the starter switch directly, and the starter switch control a relay that powers the starter motor solenoid. Starter solenoids can draw quite a bit of current, would be best to have it on a relay.

I'd have a couple of fuse boxes.

One for anything that needs constant power (is there anything on a racecar? nothing comes to mind instantly...) which is connected directly to the battery (via a decent size fusible link itself).

One for anything that is able to be functioned when the IGN toggle switch is on. Things like the starter button, heater, etc. Id power this fuse box via a relay controlled by the ign toggle switch.

That being said, I'm no expert, and my shitty writing probably makes it a bit hard to figure out what I mean... I'll try and draw some pictures :)

ProZac · Post by **ProZac** » Thu May 03, 2012 11:20 pm

Something a bit like this:

However, that's probably not ideal, as I'm using a single fuse to protect both the low current switching side of the relay, and the high power side of it. It'd work, but selecting the right size fuse would be impossible. Better to supply and fuse the switching side of the relay separately, and choose a size accordingly (2.5A) or whatever is the smallest easily available fuse you can find.

Also, For the Fuel Pump relays, make sure they're relays that include a flyback diode to eliminate voltage spikes on the switching side, as you are switching an electromagnet on here, which is an inductive load, and will spike the voltage on the line when turned off. Im sure the ECU will have protection built in, but they're not much more expensive than normal relays.

The narva 68032, http://www.narva.co.nz/products/browse/normal-open-4-5, are pretty good, I use them alot :).

Lunacy · Post by **Lunacy** » Fri May 04, 2012 10:25 am

Zac if you can draw me up a diagram like that for the bits im using il happily provide compensation of the liquid variety! That would make my life a heap easier! In fact, wanna free trip to Aucks for a weekend? haha!

ProZac · Post by **ProZac** » Fri May 04, 2012 3:58 pm

Dude, if uni wasn't kicking my ass so hard at the moment, I'd be up there in a flash.

Should be able to sort something diagram related out though :)

I'm not sure about the EMS ECU's, but I know with Link ECU's you provide the switching part of the relay with a ground to turn the relay on. This is opposite to what is shown above, which was round is yours? Its possible EMS ECU's can do either.

Lunacy · Post by **Lunacy** » Fri May 04, 2012 7:45 pm

ProZac wrote:
I'm not sure about the EMS ECU's, but I know with Link ECU's you provide the switching part of the relay with a ground to turn the relay on. This is opposite to what is shown above, which was round is yours? Its possible EMS ECU's can do either.

Yup EMS ecu provides a ground signal too.
And would more than owe you if you could draw me something up!

ProZac · Post by **ProZac** » Sat May 05, 2012 8:13 pm

http://www.linkecu.com/support/document ... eeding.pdf

That would be important also, will incorperate that.

ProZac · Post by **ProZac** » Sat May 05, 2012 9:25 pm

Disclaimer first... I'm no professional, and this is all-care, but no responsibility advice here... But it is the way I'd do things, given the knowledge I have at the moment :).

First picture is of where to put your battery cut-off switch, and where to take a constant 12v source from, that is protected by the starion factory fusible links.

Second picture is slightly more convoluted... Basically what is going on here is that there are two banks of 8 fuses each.
One bank is constantly powered, and these are the high-current fuses that actually supply power to your components (fans, pumps, ecu, injectors, etc...).
The other bank is powered by your IGN relay, and only has 12v at it when your IGN toggle switch is on. This bank is used to provide power to all your switches that control the relays for your other components.
The reason for doing this, is to separate your switch signal wiring, and component power wiring, so it can be adequately protected by the right size of fuse.

The third picture is of the components of your system that are controlled by aux outputs of your ECU. Its basically the same as above, but I've shown where I would add in the toggle switches for manual cut-off.
Definitely use diode protected relays (mentioned above) for these items, as the ECU can see a pretty big voltage spike when turning these devices off.

I really hope that is of some help to you man. As I've said, I'm no expert, but I've helped out a few mates with wiring bits and bobs up, and I haven't blown anything up.

Yet.

;).

Lunacy · Post by **Lunacy** » Sun May 06, 2012 5:48 am

Mate u are a legend for doing that :-) i can even understand it quite happily. Wil sort you out some beer next time im down in chch on the ship for sure!

Lunacy · Post by **Lunacy** » Sun May 06, 2012 5:04 pm

Just a question on the main fusible link though, would it be best to move this to just after the kill switch, so everything after that on the circuit is protected? Just can't see how i'd put a distribution block after the fusible link if i leave it as is, unless i just put an additional fuse in line from the kill switch to the distribution block. Hmmm do i make any sense??? :beer

Austarion

Racecar wiring

Racecar wiring

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