Professional Mil-Spec Motorsport ECU Wiring Harness Construction

[funkymonkey]

https://www.rbracing-rsr.com/wiring_ecu.html
 

Just finished reading this and am amazed at the things considered in professional race car wiring harness construction. Reading through it I was like "oh yeah, that'd prevent the fraying" or "oh now I get why the wire rotted" etc.

 

Great read for auto elecs as well as enthusiasts. I'd kill to have even 10% of this in my harness. 

[Duncan]

Bit slow to respond to this. I remember reading an earlier version of that article before I rewired the race car, including adding a PDM which covers almost pretty much circuit in the car (only remaining fuses and relays are the engine bay ones.)t, and keep in mind a race/rally car does need a few extras that Nissan didn't consider (rallysafe, boost logger, comms, logger dash etc)

Ultimately, in my opinion, how serious you need to be in your race car is a trade off between cost and need for reliability. I underwent the rewiring because I had added a bunch of stuff on top of 30 year old factory wiring and I was starting to have intermittent issues. Going back to a clean slate was actually simpler than continuing to build on build on build on mods.

Outcome wise, it was excellent. I made one error in the design (the kill switch requires power to operate, but the kill switch killed the PDM :rofl:). I bought a brand new factory engine loom as I use a plug in Platinum Pro (pre prod car regs), but removed a lot of unnecessary wires, and also a brand new engine sub loom. Other than that I properly planned, routed and protected all the new wiring, as well as adding high quality sealed switches for circuits (these days I would use CAN keypads, if only Haltech supported that on PPro).

There is lots of detail and pics deep in my build thread about how I went about it, but the key things were:

- All new plugs were Deutsch for quality, reliability and flexibility (easy to reconfigure if required). I used DTP for high loads like ATTESSA and fuel pumps, DTM for light loads like sensors and DT as well, all decided based on the maximum current required for the circuit.

- All new wire wire was raychem 44 (tefzel) in 2 sizes. It is all white, not because I wanted that but because it was totally impractical to buy unknown lengths of multiple colours up front. I bought 10m each of AWG20 and AWG22 and have some left of each

- All wires were labelled with a heatshrink printer (per the article) near either end of the wire, with clear raychem over the label. That has worked really well for traceability and lasted well

- Most runs were complete new pin to pin so no joining was required, but where they weren't I used crimps with integral heat shrink. They come in standard red, blue and yellow sizes and also R/B and B/Y adapters where required

- Everything is in split loom with electrical tape sealing the ends (and a small cable tie securing the tape), not heat shrink or epoxy sealed like in that article. I'm sure that is great for the super serious guys but I need to be able to pull stuff apart and fix it if I get it wrong  Plus those heatshrink boots cost an absolute bomb. Any time I used a crimp on connector outside a plug (eg earth ring or battery connection) I used double wall heat shrink for strain relief.