- Hey team, it's Tim from RaceCraft here, welcome to today's member's webinar.
Today we're going to be talking all about tyre pressure monitoring systems.
We're going to get into the nitty gritty of both how the system works and what
the data looks like and what we can use it for as well.
Before we get into that, I just want to do a little bit of a pre show here, we'll talk about
what's been happening with the shop and a couple of the things that we've got going
on on the socials.
So if we just jump across to my laptop screen here, we've got our SR86 powered GT86.
Sorry it's an SR20 powered GT86 so this is a car that I've spoken about a number of times
in the past, it's one of our shop cars that we've got.
This is a shot of it just before I came to the studio to do this webinar now so I've just taken
this, this is the current state it's sitting in at the moment.
This is, it's really getting pretty close to its final state of assembly, certainty from the
powertrain perspective.
It's had a big overhaul recently.
Just today we've had things like the inlet manifold and the intercooler piping and stuff
going back into this thing.
There's been a lot of work going on with the heat management, particularly around
the exhaust manifold and the turbo which you can see a little bit of it back here, it's a
little bit shielded by the turbo itself.
But there's really been a big update program on that and really I think this is a nice
perspective to show some of the complexities that we've got going on in the engine bay
of this car.
Doesn't look too bad with a few of the components removed but I just want to point out a couple
of things, we've got the intercooler sitting down the bottom here, stacked right behind that is
the radiator so they're actually sealed together so the air that flows into the
intercooler is forced to go through the radiator as well or sort of treating it as one heat
exchanger.
We've got the engine oil cooler package down here in one of the wings.
We've got the transmission oil cooler package down here, this is the transmission cooler pump
package down here.
You can see it's a pretty busy space to fit anything in there and it's pretty typical of
working on something that's originally designed as a road car and all of the extra cooling and
stuff we end up putting on these things, particularly for something like this which
is an endurance racing car so they typically need a lot more cooling headroom.
It sort of looks like we've got quite a lot of free space going in here between the radiator
and the engine.
Unfortunately that is space reserved for the outlet duct for both the intercooler and
radiator, so that duct sort of fits right in this space in here and feeds air out of those
heat exchangers and over the bonnet so once everything is finally fitted in there, it is an
exceptionally tight place, there's really not a lot of space for anything else but that thing
is slowly coming together.
The other project we've got going on, this is a shot of the passenger's foot well from the
same car.
So we've been doing a little bit of an overhaul of some of the packaging of the electronics.
We've actually added a second PMU or a power distribution unit.
So this is a shot here showing the mounting of the ECU, we've got one of the PMUs here,
we've got actually 2 of these fitted to this car.
So the Ecumaster, as far as I know, the most channels they do is 16 for their PMU so we're
actually using 2 of these in this car, the other one's mounted somewhere else in the car.
We've also got the Motorsport Electronics main relay here which is essentially like an
electronic killswitch.
Which is really nice 'cause it means you can simplify some of your heavy cabling,
things like your large diameter battery cables can be kept a little bit shorter because we don't
need to run those all the way out to a killswitch that's accessible in the car, we can just have a
tiny little killswitch somewhere externally on the car and then we've also got our little
telemetry sender here.
So that means that we can, when the car's on track we can send live data, obviously it's being
logged onboard inside the logger itself but it's also being sent over telemetry back to the
engineers in the pits as well.
Now our logger is actually part of our dash unit in this car so it's a combined MoTeC logger so
that's why it's not shown here in this picture but there has been quite a lot of work going
into tidying up some of the wiring, you can see it's got a relatively serious wiring harness
built into this thing.
We've added some of these new style quick clip connectors, I forget the actual brand of
these but they're a really nice little system, essentially it's got a little tab switch on top
which means you press down that little switch which is just that little red bit you
see sitting on top of both these things.
You essentially pull that switch in and they pull off a post.
So it's a really nice quick disconnect, it's also a nice reliable system rather than having big
ugly terminals that you've got to unbolt.
So we've used those all throughout all the heavy cabling, things like the battery,
the alternator, the starter, the main relay, stuff like that, it's been a nice addition to
that car as well.
Other stuff that's been going on in the workshop, our RaceCraft GT86 which is
the one that's conventionally powered with the original engine but a turbocharged version
of the original engine.
We've been doing some more cooling updates so we've got these fences that we've got sitting
in here that you can just sort of, they're painted black intentionally to sort of keep
a low profile but essentially they're these little sections there that are there to help
guide flow through both the intercooler and the radiator as well.
So both of those seal against the inlet of the front bumper and we've got the, this is actually
the factory style undertray that's fitted here that kind of seals against he bottom of the
bumper.
The idea here is to make sure that all of the air that's at the front of the car is
actually making its way through both the intercooler and the radiator.
One of the other things we've been working on recently is adding these brake ducts so
these are actually 3D printed which is a really nice use of a 3D printer, there's all
sorts of different materials out there you can use for printing.
These particular ones, they're not in a hot environment, they're not in a particularly
difficult environment from a materials perspective so we can actually use the
PLA material we're printing as an actual functional part without it being a prototype.
This is a couple of other views here, it's a little bit closer of the same thing, you can sort
of see this basically follows the, roughly the profile of the bumper skin on the outside.
So basically all of the air is either directed through an intercooler and a radiator or
it's directed to go through the brake ducts and these have got a hose connection
on the back of them here.
I think there's another shot here, this is, you can see the flexible hose which is a little
bit again relatively typical of a factory style road car with these hoses have got
a relatively torturous path to get back to the cooling veins on the disc so essentially
this part here of the brake duct mounts to the front of the car.
Then you've got a little bit of flexibility running back to a hose running back into
the wheel arch and to the calliper itself.
So that's a couple of projects we've had going on in the workshop here.
Like always there's a relatively large amount of work going on in both improving and developing
the cars and also using them for making more course material as well.
So we've had again more stuff come up on the, sorry we've had more good content
coming out on the YouTube channel.
There was this video that came out, I think was just released yesterday, talking about
brake knock off.
So for anyone that is not familiar with the term knock off, it's essentially when you've got your
brake disc mounted on the side of your brake calliper, when you've got any compliance
or any clearance in there, so that I mean by that is often you've got a situation, well almost
always the situation is that the brake disc is mounted to the hub and the hub is
obviously what is mounting the wheels.
So if you've got any particular things like a lot of wheel bearing clearance or a lack of
stiffness or compliance in the system, what you end up with is that disc kind of rocking within
the calliper so the calliper is mounted rigidly to the upright or relatively rigidly,
hopefully rigidly to the upright and you've got the disc and any, let's say you've got
a lot of wheel bearing clearance for example which is a relatively common situation that
means the disc has got some freedom to rock back and forth in an axis it's not
really supposed to do.
It's kind of what you see in this video here with it rocking back and forward.
The purpose, the reason that's a problem is because what it ends up doing is actually
pushing the brake calliper pistons back into the calliper.
The problem with that is that it means when you go to apply the brakes, some of the brake
travel that would usually be used for squeezing the pads against the disc is first used up in
just pushing the pistons right up against the back of the brake pads and the brake pads right
up against the disc.
The reason that's a problem is when you go to hit the brakes, that will mean you've got
an extra long pedal, so you'll actually have quite a lot more pedal travel before the brakes
will start engaging.
And that's what is typically called brake knock off or in some parts of the world,
brake knock back as well.
This typically happens, you see it a lot in touring cars when they're racing on things
like street circuits so a really bumpy circuit or places with big curbs where the wheels
are getting a really hard time, they're getting knocked around and this is where
you get any of those compliance or clearance problems will be aggravated and be made
much worse.
So typically at places where you've got cars running over curbs and really rough
surfaces, what you'll often see happen is drivers pumping that brake pedal up before
they get to the corner.
So let's say they're heading down the longest straight, you'll often see them, while they're
still accelerating, maybe use their left foot just to tap on the brake pedal just very
very lightly just to pump the pistons back out and get them back in contact with
the back of the pads so they know when they go to hit the brakes at the end of the straight,
they know they're going to have a good brake pedal when they get there.
So this is a video just talking about some of the intricacies of that.
Couple of different ways that you can deal with that, different ways you can get around it,
ways you can solve those problems.
It's definitely a video worth checking out, particularly if you guys know what I'm
talking about when it comes to brake knock off, it's not a very nice feeling when you're
inside the car.
On our forums, again they've been relatively active recently.
There was this question, I think it just came up maybe even yesterday, from one of our
members James Mewett who has questions about transmission and differential
temperature limits.
So this is something that a lot of people, particularly when you start elevating power
levels will be having troubles with where you've got a car that's got, you've got a temperature in
both your transmission and in your diff, if they're separate which is much higher than you want.
Now there's a couple of problems with that, one of them is obviously problems with the
mechanical aspect, things like bearings in the gears themselves.
But the more pressing problem that tends to happen is the oil breaking down so when
the oil gets too hot, it tends to lose its ability to keep a fluid film between each of the
mechanical components and James' question was basically just searching for a little bit
of an answer, few answers about how hot is too hot?
Now ultimately this discussion lead onto, actually ended up being a really great
discussion, not just about temperatures, about also the practicalities involved with
cooling of transmissions and diffs and some of the things that maybe aren't straight
away obvious to people that haven't dealt with this before.
It's really typical, particularly in James' case here, so he's got a circuit racing
car with a fully flat floor so that means essentially that the transmission and the diff
are sitting sandwiched between the flat floor and the chassis itself.
Now that's really great from an aerodynamic perspective but from a cooling perspective,
suddenly you've got a whole lot less ambient air that's got access to basically
passively cool those housings.
So this is a situation where you quite often end up with having to have external oil
coolers, both for the diff and the transmission, this is something that certainly in our SR
powered GT86 has got, it's both got separate transmission and diff coolers.
This is something that's definitely a requirement in that car and it's something that's pretty
typical you'll see, particularly of anything that's running in an endurance series or
especially if they're running elevated power levels over stock.
This is just basically a little bit of a discussion on getting specs from your
oil manufacturer, some of the practicalities involved and I thought it actually turned into
a really interesting conversation so I definitely encourage you guys to jump
over to that forum post in the general discussion section.
Now we have got, as always we've got more courses in production.
We've got our race driving fundamentals course which will be being released soon,
it's in its final stages of production.
And also our professional data analysis course which is going to be coming out
at the end of the month and there's definitely going to be a really strong
follow up to our data analysis fundamentals course.
We'll be touching on a little bit of that stuff that's discussed in the professional
data analysis course in today's webinar when we're talking about tyre pressure monitoring
systems.
So guys that's the end of the pre show, I'll be back in a second and we'll start
the lesson itself properly.
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