Race Wiring Diagram

[260DET]

For the Z31 project, it will have an aftermarket ECU, electric fuel pump and so on, just the usual basics. I was thinking of having separate switches for the fuel, ECU and ignition systems so that each could be activated separately when testing etc but normally they would be  left on with one master switch and a push button starter doing the usual starts. Found the diagram below which looks OK, expert advice and comment please.

Edited January 3, 2018 by 260DET

[GregTas]

Only had a quick look. One thing of note is the fuel pump relay must be operated by the computer. This is a safety feature so that if the engine is not running the fuel supply is switched off. A crashed car with a broken fuel line still venting fuel at 45psi is not ideal.

 

You can still have your switch in series with the ecu trigger wire to the relay coil if you feel you wanted a switch. Mindful that everything in the electrical circuit is just another possible point of failure.

 

I also not you have one relay, relay 3 supplying the lights and the ecu. ecu would normally have its own relay. It's a critcal system, others are not.

 

The dash and brake lights do not need to be powered by a relay, just switched with fuse. Ign switch (assuming decent switch) could do this.You could have the ign switch powering relay 3 for the ecu only.

 

I'm not sure what that hot/cold box on the top left is. Is the light switch in the circuit somewhere?

 

Also fuses need to be first thing in the circuit so everything downstream is protected. Relay 3 is not protected, nor are all the switchs and wiring. If a wire has a problem it will just keep smoking.

Edited January 3, 2018 by GregTas

[260DET]

Thanks Greg, the diagram is courtesy of Mr Google. Yes, having separate switches for fuel, ECU and ignition is not really necessary I guess and as you say the ECU controls the fuel pump, can always pull fuses for any testing. It might be an idea to have a keyed master switch to activate everything and use a toggle switch and a push starter button, both mounted on the transmission tunnel, to start the engine. On a race day the master switch can be left on so to start the engine only the toggle switch and button need to be used. No keys to worry about.

 

I have a 8 circuit DIY wiring loom, just want to get the final design and layout right. There is electric steering but given it will draw a lot of current it's own separate circuit seems best using a high capacity relay and a circuit breaker.

[GregTas]

Anyone can put things on the internet and so you have to filter through the rubbish to get the good stuff. The person that drew that circuit seemed to lack in good design principles. I wouldn't have them wiring up my car.

 

I feel I'm not just another internet expert because I'm a qualified Auto Elec. and have wired up a few cars, including race cars, some from scratch and some with aftermarket EFI systems.

 

I think it would be good if you spent the time coming up with what you want for your car and then drew it up before you start. A good diagram will make the job much easier and also be a good reference when you have faults later on.

 

For the diagrams:

• Fuse boxes should have the detail of each fuse (not just one big in/out box),
• Relays should show all pin ids i.e. 85, 86,30, 87 etc., It's not as simple as 'coil' relays can create voltage spikes on switching which can upset electronics like the ecu. Diodes are placed across the coil to prevent this (85 and 86). So you need to ensure the coil is wired in the correct way around.
• Detail wire colours being used and even wire gauge. 4mm wire is a waste on a relay switching circuit because it's twice as big as needed, but a bit small for the alt. output

 

Spend the time now to get a good result. Dodgey wiring can stop a car just as quickly as a blown engine.

 

Goodluck, Greg

[260DET]

The engine to be used is already wired up to a Haltech ECU with it's own loom so that will make things simpler. Yes, I will draw up a wiring diagram both for the install and to keep in case of problems later on.

[PZG302]

My comments would be to KISS, no keys, just a master switch and then switches for the ignition?ECU and fuel systems. The others such as lights (headlights, tail lights) on its own circuit, brake lights a separate circuit, wipers a separate circuit.

 

Also look at doing things like running the brake lights in series so the circuit would go one wire from positive power through fuse or circuit breaker to the brake light switch at pedal box to the first brake light globe to the second brake light globe to earth.

 

I would also look at instead of fuses using circuit breakers for not so critical circuits but where you want to be able to reset and use again, such as wipers.

 

I will be doing the PDM path for the S14 as the ECU, dash and the associated wiring costs mean the extra for the PDM and incorporating the rest of the wiring harness make it worthwhile. So I will have a switch panel mounted within arms reach, probably on the transmission tunnel and then a the big turn it all on and off switch panel near the base of the gear shift, again within easy reach, and the start button will be as big as practicable so it is easy to find and push with a gloved finger.

 

 

Also make sure the power isolation works as per the CAMS requirements (in bold below) and take this into account in your wiring design.

 

SCHEDULE C

Each automobile in a circuit race (except a superkart) shall, of necessity, in addition to the provisions of Schedules A and B, be fitted:

(a) only with laminated glass in any glass windscreen. Windows, including windscreens, shall not be coloured or tinted unless fitted as standard to a production automobile and compliant with AS2080;

(b) with wheels and tyres in compliance with Schedule E. No tyre shall have been retreaded, recapped, repaired or re-conditioned in any way;

© with bodywork which generally encloses (when viewed from above and each side) the chassis frame and basic mechanical elements, from the front of the automobile rearwards at least as far as a transverse vertical plane immediately to the rear of the driver’s seat;

(d) with not fewer than two functional rear vision mirrors each of at least 50cm²;

(e) with a fuel tank as specified in Schedule N;

(f) only with such replacement seat which in closed automobiles first registered with CAMS after 1 January 1980, and in which the relevant regulations permit the replacement of the driver’s seat:

(i) incorporates a head restraint; and

(ii) does not incorporate adjustment of the rake of the squab. The use of a seat to the FIA 8862-2009 Advanced Racing Seat standard is recommended. Where a seat to this standard is required, the seat shall be used with the seat mount bearing the same FIA homologation number unless an alternative seat mount has been homologated by CAMS, in which case that seat mount may be used.

Additionally:

(g) Where an automobile does comply with the Australian Design Rules (ADR) for seat mountings, the seat shall be mounted to the main structure by not fewer than four grade 8.8 bolts of minimum diameter 8mm. Where the seat is affixed to an un-reinforced section of the floor pan, each attachment point shall be reinforced by the use of a plate of not less than 75mm x 50mm x 3mm;

(h) On each automobile, other than those of the 5th Category, fitted with an electric fuel pump, the pump power supply must cut off in a maximum of six seconds after the engine stops;

(i) Each automobile of the 2nd and 3rd Category shall be equipped with a battery isolation (master) switch which isolates the battery and stops the engine, and:

(i) it shall be capable of being operated by the driver in his normal seated position;

(ii) there shall be a second switch, or a remote means of operating the main switch, from the vicinity of the base of the A pillar on the driver’s side or, for an automobile with no A pillar, in a comparable position; and

(iii) each external device shall be clearly marked by a symbol showing a red spark in a white-edged blue triangle of minimum edge length 150mm;

(j) For a non-road-registered series production automobile any cable-operated bonnet or engine cover release mechanism must be disabled and replaced with at least two fastening systems in accordance with Schedule B;

(k) Each automobile shall be fitted with a window net as required by Schedule I.

Edited January 4, 2018 by PZG302

[260DET]

What about those master kill switches that also isolate the alternator?

[GregTas]

I'm going to put on of these in my car for the kill switch. They have the main switch and a second one that can be used to kill the engine.

 

https://www.tasautosport.com.au/accessories/fused-battery-isolation-switch-6pin

 

https://www.12voltplanet.co.uk/battery-isolator-switch-removeable-key-with-ignition-isolation.html

[260DET]

Like this one here Greg http://www.ebay.com.au/itm/Battery-Isolator-Switch-Cut-Off-Disconnect-Power-Kill-100A-Key-For-Car-Van-Boat/253244781027?epid=3008782693&hash=item3af690b1e3:g:iRAAAOSwUYNZ~-ZJ

[GregTas]

It looks the same, but the ebay one may not be up to it. The ebay one doesn't have a short term rating i.e. cranking engine listed. 100A will not do it.

 

The two I listed are also 100A switches (continuous), but have the short term ratings listed of 500A for one and 1200A for the other.

[PZG302]

I would have the plastic key mounted somewhere out of the way and weather, UV is not kind to them over time and use two pull cables to activate, one at the base of the A pillar on the driver's side, and the second where you can easiliy reach it in a worst case scenario, i.e. car on roof, if ni HVAC controls the panel that covers those holes is a pretty good location.

 

Or you could go for overkill and go to one of the fancy pants versions like this.....

 

https://www.demon-tweeks.co.uk/performance/battery-isolators-master-switches/cartek-xr-solid-state-battery-isolator

[260DET]

I would have the plastic key mounted somewhere out of the way and weather, UV is not kind to them over time and use two pull cables to activate, one at the base of the A pillar on the driver's side, and the second where you can easiliy reach it in a worst case scenario, i.e. car on roof, if ni HVAC controls the panel that covers those holes is a pretty good location.

 

Or you could go for overkill and go to one of the fancy pants versions like this.....

 

https://www.demon-tweeks.co.uk/performance/battery-isolators-master-switches/cartek-xr-solid-state-battery-isolator

 

Over $400, the price of some of this sort of stuff from motorsport retailers is ridiculous given what that would cost to make.

[260DET]

It looks the same, but the ebay one may not be up to it. The ebay one doesn't have a short term rating i.e. cranking engine listed. 100A will not do it.

 

The two I listed are also 100A switches (continuous), but have the short term ratings listed of 500A for one and 1200A for the other.

 

Have ordered a ebay one Greg, will let you know what the quality looks like. Being in a country town I buy a lot of stuff via ebay, most of it is the same as what's sold in Aussie shops. Not always of course, sometimes the more expensive stuff warrants a knock off.

[PZG302]

It showed it was FIA compliant so should be OK, also looked like the other links.

 

Just make sure the ECU will turn off the fuel pumps within the 6 seconds.

 

The way the green car was done meant that it was two turns of the key to prime the fuel system before you turned it to start the car.

 

Was something I always wanted to change but never got around to doing was taking the key start out, button would be easier in the situation of stuffing the start up and stalling on the grid with the other cars coming through. For sprints obviously you won't have that problem.

[GregTas]

It showed it was FIA compliant so should be OK, also looked like the other links.

 

The FIA regs are around the functionality i.e. it has the capability to shut off the ignition and fuel systems, not the rating or quality.

 

The ebay switch may be just fine and it's even possible all those switches came out of the same factory in China, but with the ebay switch being $14 AUD (with postage)  you have to wonder about the insides of it and whether it has three sets of copper contacts in there like the other more expensive switches.

 

Perhaps I'm just fussy and overly cautious.

[260DET]

While I think of it here is a wiring diagram for the said FIA master switch.

[260DET]

The Ebay switch looks OK, the plastic handle has a brass pin where the switch turns, the nuts are brass, there is nothing on the outside that indicates it's of poor quality. I don't take much notice of price as an indicator of quality any more on basic items, seen ridiculous amounts of mark up on Chinese made items here that I've bought on egay from a retailer in China..

[d3c0y]

I used an eBay one for lemons and it was fine. Running all that 0 gauge wire is really expensive and we also had to run a wire pull to turn the isolator off from outaide the car which was another tricky one.