- When it comes to motorsport, the reliability of the wiring harness is one of the most
common reasons we see cars fail out on the racetrack.
And with the amount of money being poured into preparing a racecar and then attending
a race meeting, this sort of reliability problem really is inexcusable.
So this is where motorsport wiring comes into the game, getting a proper well built,
reliable wiring harness that we know we're not going to have any problems with.
Now I've got Chris from 12v Performance here in Australia who is responsible, a lot of jobs
obviously here at World Time Attack but in particular he's wired up the Tilton Evo,
Tilton version 2.0 behind me.
So Chris, for a start let's just go back and I want to find out how you actually got involved
with motorsport wiring, it's one of those industries that's incredibly difficult to find
solid information on and in general there's not a school that you can go to and
actually learn that, so how did you get involved?
- Originally I worked on a project that was already previously wired from a guy
with a lot of experience in wiring.
And I, at that stage I was working on building looms, mainly a lot of lower end ECUs.
And I thought wow this is great, where do I learn?
That was pretty much the basis to start.
- So originally you're building the more garden variety wiring harnesses and you've
seen this professional motorsport wiring harness come through the door and it sort
of lit up your eyes and you've kind of wanted to aspire to learn how to do that?
- Yeah that's correct and then plus there was an ECU company I was doing a bit of work for,
Emtron ECU and that kind of pushed me to, they wanted to be the higher end of the
market, they needed the back up from the wiring so it pushed me to learn.
Unfortunately there wasn't a lot available at the time to learn from so it was a lot of
trial and error on previous jobs that I had done and I'm a little bit OCD as well so
neatness is imperative in my profession and always just strive to make a neat loom.
So you try different methods, there's obviously, you can see stuff on Instagram
and Facebook and whatnot and yeah you just, you kind of like follow the leader
in a way, you see guys in other industries, Race Spec is a good example,
his looms are incredible.
And that's the level that I wanted to be so I just keep progressing and yeah.
- Yeah I think it's reasonable to say that these techniques aren't impossible to learn,
as you've kind of pointed out.
It's difficult to get solid resources on how to learn and seeing the likes of these sort of
professional motorsport wiring harnesses being posted up on Instagram, gives you that sort
of information, you can sort of see, oh yeah I can see how they've done that and then
you can start applying that and developing your own skill set, that's sort of the way it's
gone, testing and refining?
- It has in a way yeah but you do stumble on little small issues along the way and you
just improve and a lot of it was mainly heat which introduced me to start using Raychem.
The biggest part was the concentric twisting, it's getting that right.
So yeah concentric twisting is great but your layers had to be set in a certain way to get
the weight reduction out of the harness and to get it looking nice, where the OCD part
sort of kicks in.
- Yeah there's a huge amount of planning that comes into concentric twisting.
We'll come back to that but I think probably for our viewers who are thinking to themselves,
well what actually makes for a, I use the term, professional motorsport wiring harness.
We quite often hear the term milspec being thown around, sometimes with people not
really understanding the implications of that term.
But for you, what would you define as the difference between a garden variety wiring
harness that you'd see in your everyday enthusiast street car and something like
you've built here for the Tilton Evo?
- Yeah most of it's really just the wire.
Motorsport wiring is Tefzel wire so there is a huge difference between the Tefzel wire and a
TXL general wire, mainly the heat.
Secondly there's the stranding, and thirdly would be the fact that it's tin coated copper
and TXL is copper.
So you fall into water problems.
- The other thing I think that's worth mentioning there is that the TXL versus
the Tefzel wire, you mentioned the heat rating and TXL insulation, generally around
about 85°C versus 150°C for the Tefzel wire insulation, but the other important thing
for motorsport, obviously weight is key and size is key and that Tefzel insulation,
incredibly thin compared to the TXL.
Now moving on, it's not just about the wire as well, we've obviously mentioned the
concentric twisting but it's also the connectors and the insulating method that you use so
can you talk to us a little bit about those differences?
- So the tooling that we use is, like we only use proper...
- The DMC tooling?
- Yeah the DMC tooling.
- The techniques or the tooling required to properly terminate an Autosport connector.
- Yes that's correct.
- And those Autosport connectors, that's one of the areas we see these really nice easy
to work with, bulkhead connectors but unfortunately they're also cringingly
expensive yes?
- Unfortunately they are but at the end of the day, the results speak for themselves.
- In terms of the Autosport connectors you've got there, the other aspect is that with a
proper motorsport harness, it is really well sealed from environmental impact such
as moisture and dust ingress so can you talk to us a little bit about the techniques
used for sheathing the harness and then also sealing the back of those connectors?
- So there's a couple of different options, depending on the harness depending on
the complexity of the car.
So if we know that a harness is going to be in an environment where it is going to get
oil in it and whatnot, we use a resin behind the boots an that ensures that the harness is
going to be attached to the boot, waterproof.
- So you've just mentioned boots there so you're talking heat moulded boots,
so these are what seal the back of the connectors?
- That's correct yes.
- But that resin really takes that one step further, making sure you've got no chance
of moisture ingress?
- That's correct yes.
- So when it comes to planning a wiring harness for the likes of the Tilton Evo,
can you kind of give us some insight into your thought process, where do you get
started?
- OK so first of all you need to spend a bit of time on the car and understand what they
want to do with the car, we've got a list of sensors that we need to run, then we sit
down and work out what devices we need to use.
We have basically a plan put together from the data guys of what they want and so it's just
a step by step, this goes here, that goes there.
So straight away you have to in your head work out, you know it's like...
- Bit of a jigsaw puzzle?
- Like a jigsaw puzzle.
You've got items in certain places of the car, you have to get one wire from A to one
wire to the B.
- So once you've got a bit of a plan on where all of the components lie in the car,
do you go ahead and then design a dummy loom to get all of your lengths correct first,
or how do you do that, is that sort of all part of your documentation and then you
can just build straight off that?
- So what I normally do is everything is measured so I know from certain points
of the car where things need to be.
Upon building that harness, it kind of constructs together.
- Everything, you know that it's going to be in the right place before you actually
start cutting wires?
- That's correct yeah.
- I think that's probably one of the things that even at the enthusiast level I see so
many people wiring cars overlook is properly planning.
And there's an old saying that I really like is failing to plan is planning to fail.
So it's really important, you take the time and it might feel like it's wasted to start
with but spending a few hours actually planning out what you're going to do,
where you're going to put your wires and then documenting that, makes the rest
of the process actually go so much faster.
And then you've got that documentation to refer to later on if there is a problem?
- That's correct yeah so everything is written in an excel spreadsheet and so everything
is related, break outs.
- And particularly in the heat of a race meeting here, if by chance there is a
problem that needs to be fault found or you want to make a minor change,
having that documentation does make that so much easier.
Now you mentioned the technique of concentric twisting and anyone who has
an interest in motorsport wiring has probably seen a sample, a photo
of a concentrically twisted harness and I know in particular if you haven't done
it before, it can be a little bit confusing what's going on there.
So can you talk us through what a concentrically twisted harness is?
- It's basically wires twisted together in different layers.
It's strain relief and flexibility for the loom so you can go around corners,
there's no strain in the wiring.
And plus there's yeah just the flexibility.
- So I think it's important to mention there, one of the reasons we get that flexibility
is that the individual layers can basically slide or move relative to the other layers
and what you've just mentioned there as well with strain relief which is really
important for reliability.
It makes sure that no individual wire in the concentric twisted harness has got
any more strain applied to it than any others.
There are some downsides though in terms of the use of filler wire et cetera.
Can you talk to us about what that term filler wire is?
- The filler wire is basically just a dummy wire to fill in the layers to make the layer
complete so there's no humps in the wiring.
- Because each of those concentric twisted layers has to have a certain number of wires?
- That's correct yeah so the hardest part in concentric twisting is you've got x amount
of wires and you have to make them all complete so you start playing around with
different base layers and different numbers and that's where it starts getting
complicated.
- So you're talking about basically trying to work out your layer numbers so that you're
minimising the need for filler wire?
- That's correct yes so again you're trying to get the weight out of the harness.
So a good example you might have two 12 gauge wires and 24 22 gauge wires.
And unfortunately in experience, that you need to understand how many wires
you're going to need for your next layer and then you're left with x amount of wires
and if you have let's say you've completed a layer and you have seven wires left,
then you might need to add another 20 wires.
- Which doesn't make a lot of sense right?
- It doesn't no, the harness gets heavy.
- So again that really comes back down to the planning and how important that is right
at the outset?
- That's correct yes.
- Now I think one of the aspects that's often overlooked is yes this is a beautiful looking
harness when it's complete, it is going to be reliable, that's great particularly at
professional motorsport level where budget is no issue.
But for the enthusiasts at the sort of grass roots level, enthusiast level, who are aspiring
to own one of these harnesses or maybe build their own, it's important to mention,
there's a huge amount of time that goes into this and time of course is money.
So could you give us some ballparks, obviously it's going to depend on the
specific job but not in terms of money specifically, but I mean how many
hours would you typically spend on constructing a harness?
- Well an engine loom you might, between 20 to 40 hours.
It just depends on your sensors and your inputs, your outputs and whatnot.
Plus a lot of guys that we sit down with before we build the harness, we'll sit down
and say hey what do you want to do with the car?
You might not have everything on the car now but you want to allow for that,
'cause obviously when you start adding on into a loom, that's when it starts looking bad
and problems can happen.
- It's one of those points as well with a professional motorsport wiring harness with
DR25 sheathing and moulded boots, it's very difficult to then make significant changes
to that harness and add on so this is what you're talking about.
Basically future proofing the harness, getting all of those potential upgrades
at least into the harness right from the get go, even if you might not be using them
initially?
- Yes that's correct.
- Alright look Chris it's been great to get some insight into what goes into these
harnesses, you've done some beautiful work here, particularly on the Tilton Evo behind us,
if people want to find out more about your work or reach out, how can they get in touch?
- Just look us up on Facebook, 12v Performance, or even Instagram, 12v Performance.
- Perfect, keep up the good work, that's Chris.
- Thanks mate, appreciate it.
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