Tips for replacing wiring harness. Solid state relay box?

[dalla]

Hi guys
I am building a Renault 5 GTT Hill climb car.
The car has previously been raced, but it is somewhat of a hack job.
The wiring harness is totally ruined. Both the engine harness and the dash harness has been severely cut and messes with.
It is virtually impossible to get a new harness for these cars. So I am contemplating making my own.
I am looking for some tips on making a basic race spec wiring loom. Thinking I will run at stack dash. I am thinking of making a separate engine loom for ignition, cooling fan etc. And then another stand alone harness for all the lighting, wipers etc.
I am looking for some inspiration and tips on how to do this? Is there any solid state relay boxes available for race cars?
Thinking of something like the Motogadget M-unit used on many custom motorcycles.
https://motogadget.com/shop/en/m-unit-digit-taster...

Kind regards
Dennis

[Josho]

Would it not be cheaper just to have yours repaired?

[Krikkit]

If you're planning on doing it all yourself I'd pick up a textbook on how to do it properly before you start.

I've heard from a friend this is quite good: https://www.amazon.co.uk/Automotive-Electrical-Sys...

[dalla]

Josho said:

Would it not be cheaper just to have yours repaired?

It's beyond repair mate

[gazza285]

Any reason not to use the relay shown? It will work just as well in a car as on a motorcycle.

[Riley Blue]

Rather that start from scratch, couldn't you adapt something from here?

http://www.gt-turbo-spares.co.uk/cart/index.php?cm...

[JohnMcL]

Take a look at www.infinitybox.com I used this to wire a kit car. It was really easy with a canbus and many pre-programmed features.

[bolide]

How many relays does the car need? Ordinary relays are a known quantity, are cheap & easily replaceable and I can't see a real need to replace them with something expensive and (probably) unrepairable

As it's a race car you don't need lights, windows, etc. There's actually not that much that you do need apart from engine systems, cooling fan, instruments and a demister fan & wipers if you run in the rain

If you make your own loom it's easy to hack it about to make changes & move things. Things always change after the planning stage

I built a loom for a 4x4 racer and one thing I learnt was that cooling fans take a big current and have a huge start-up surge. You'll need at least a 30 amp relay, appropriately-sized cable and as few cable joins & connectors as possible. After that, everything else is pretty easy

Nick Froome

[Megaflow]

gazza285 said:

Any reason not to use the relay shown? It will work just as well in a car as on a motorcycle.

It won't cover all the functions required in a car, such as wipers, washers, fog lights, etc.

Immensely clever unit though. A mate just build a bike with one, you can run the tail/stop light with a single power wire, it sends just the right amount of power for a tail light, brake and it increases the power to increase the brightness.

[Crafty_]

I'm sure kit car places can offer something similar, but in the hot rod world you buy a wiring kit, something like this: http://www.ezwiring.com/store/viewitem.php?product...

Each wire is stamped with what it does every couple of feet, cut to length & terminate. There are a number of suppliers and different products that offer different numbers of circuits.

You'll need your own starter/alternator circuit and an engine harness for sensors (assuming its running injection of some sort)

[dalla]

JohnMcL said:

Take a look at www.infinitybox.com I used this to wire a kit car. It was really easy with a canbus and many pre-programmed features.

Exactly something like that I was looking for. Quite expensive though. I like that EZ wiring too. Might also be a possibility. Car is road registered by the way, so will need lights etc..

[drmotorsport]

I've just completed rewiring my Ford Puma race car from scratch using the Omex loom for engine related stuff, and making my own fusebox and loom with bits from Car builder solutions and Auto electric supplies. I did spend a long time planning the circuits to minimise wiring while keeping appropriate wire gauge and fuse sizes before the build. I also made sure i used proper OEM grade connectors for the important stuff and good quality crimpers etc.

[anonymous-user]

Why does that infinity box still have fuses in it?? If it's truly solid state it should be using smart high side swtiches with built in diagnostics / current limitation!

[JohnMcL]

For a UK solution, how about https://www.bodylogicuk.com/ from Simtek UK. I have used their wiper controller to operate wash/wipe/intermittent/headlight wash from a Ford column stalk to non-Ford motors. Elegant unit with internal re-setting chemical fuses

[Penelope Stopit]

Have you managed to get all the information you need for this job?