- It's Andre from High Performance Academy
and we're at World Time Attack,
with Mitch from Haltech and we're going
to be talking about Jarrod Meg's
R33 Open Class race car.
Now, Mitch it's a beautifully presented car.
I know that you've had some, some involvement
with the technical side of the ECU tuning
and we wanted to really talk about what, exactly,
makes a competitive open class car tick.
Certainly this year, the competition
has stepped up a lot in this open class.
For a start, let's talk about what makes it, what powers it.
Can you tell us the engine that's in the car?
- Yep, so at the moment it's a 2.8 Litre RB engine.
So yeah, factory 26 block with a stroker kit put in it.
Turbo-side it's a precision 68/70,
little bit different on the exhaust manifolds, too,
actually run like a Pro Mod-style manifold,
which gets the waste gate right off the front
of the motor, very important for cooling.
One of the GTRs you have cooling issues
with waste gates and exhaust systems.
We've done that.
Electronics side it's a Racepak Smartwire for a PDM.
That integrates with the Haltech Elite 2500.
- Let's just, before we get into the electronics,
I just want to focus still on that engine package.
So we've got the RB28, we've got the precision turbo,
and just in terms of the power it's producing
and the boost level, can you let us know what that is?
- Yep, so we run the engine on ethanol E85,
32 pounds, the car makes 600 kilowatts
at all four on our Dyno at Haltech.
It's a pretty stout package.
- It's getting the job done.
Okay, now moving on to the electronics package,
and you've got the Elite 2500 ECU in this,
now, obviously, when you're pushing an engine that far,
that hard, and it's been beaten up on lap after lap,
when you're running that sort of boost pressure,
a lot of room for error, a lot of things that can go wrong.
So what in the Elite ECU is being
utilised to try and safeguard the engine
and make sure it does remain reliable?
- Yeah, so we've basically put as many sensors
on the engine that we can cram in there.
Along with all of that data to basically
feed all the closed loop systems in the ECU itself,
and then have those systems have a long-term procedure
to basically learn the more that the car's out on the track.
- Now this is one of the benefits, I guess, that
Haltech introduced with the Elite ECU and it is relatively
unique to the Elite ECU is this long-term or self-learning.
So just for our viewers who aren't aware of how that works,
you've got a system that, let's say for example,
we're talking about boost control, over a long-term,
it can, if the boost isn't reaching the target,
it will adjust a long-term trim
so that your boost remains consistent, correct?
- Yes, spot on, so with the boost control example,
we have a base duty cycle table,
based on your target pressure.
The ECU looks at what your base table is,
compared to what it actually needs
to get to the target, and it then populates
that long-term table over time, with that difference.
- Now, from your own experience with tuning,
if you looked at the benefits of having
that additional long term trim, over just a well-tuned,
closed-loop boost control system,
what sort of advantages are we likely to see?
- Yeah, look, don't get me wrong,
you still definitely need to tune the closed-loop system,
the long-term trim is there really just as a trim.
The benefits I see are sort of environmental changes,
and especially with a car like this
that does get very, very hot and the driver
does like to do multiple laps.
Yeah, when you're talking heat and differing
environmental stuff, like air temperature
and just the temperature of the day,
you will see the trim sort of picking up that
different, sort of morning to afternoon.
- Yeah, and definitely from the cool of the morning
to the heat of the middle of the day
and then again it tends to cool down in the afternoon,
and that's all going to affect the way the engine
performs and that boost pressure.
Let's move on, and you mentioned
also closed-loop control for the fueling.
Now, I know that a lot of tuners won't rely
on closed-loop or don't like to use closed-loop control.
Let's talk through that and give us
the pros and cons of using closed-loop fuel control
any time the car's out on track.
- Yeah, so obviously with the lamda in the exhaust
system, we can obviously sense that
the air-fuel ratio at all times.
We've got our target lamda map in the ECU as well.
Probably again, environmental changes, heating the engine.
Of course your base fuel table does
need to be really well tuned.
- Actually, I'll just touch on that as well,
because I know that a lot of tuners are,
particularly novice tuners, think that these
closed-loop systems are a fix for actually not
having to do the job properly in the first place.
You still actually need to tune the engine.
- Oh, 100%.
You know, our system will allow you to trim
plus or minus 50% in the short term,
and the same in the long term, but that may be okay
if you're just idling around town to get
your rough shape of your base map in your standard car.
In a car like this, and really any car that, you know,
a tuner has to do the fuel mapping on, it does
need to be correct in the first place.
The O2 control is there just as a safeguard
and to keep everything, basically, yeah, on target.
- Now moving on as well, you've got an Albins sequential
gearbox in the car, and again the Elite is controlling
the gearshift, ignition cut, I'm assuming, on
upshift, but it's also closed-loop,
so can you talk us through that system?
- Yeah, so we've got a load cell
on the gear shifter, the ECU looks at that.
When the ECU detects a request from the driver,
and all of the parameters are met,
so we have a min throttle position,
a minimum engine RPM, and the ECU actually needs to know
what gear it's currently in, the ECU will initialise
a cut, so we can have a configurable percentage
power reduction on the engine, which can either be done
with fuel, ignition, ignition retard,
a combination of any of the three.
So on this car, we're purely just using an ignition cut,
with about 90% power cut.
Once that happens, the ECU then looks
at the barrel position sensor of the sequential,
waits for the sequential to engage the next gear.
Once the ECU knows that the sequential is in the next gear,
it'll then release that cut
over a pre-determined mappable time.
- So that cut is as long or as short, hopefully, it's short,
as it needs to be, - Exactly.
- for the next gear to be engaged.
Now, give us the advantages, mechanically,
of that system over the more traditional,
or older, just a physically time cut.
- Yeah, so with a timed cut, you basically have a set time.
Every time there's a gear request come through,
with a closed-loop system, obviously, between every
gear and differing engine speeds and engine loads,
that cut time is going to change, especially,
even with say a mid-shift, when maybe the driver
doesn't quite pull on that shifter hard enough,
the barrel may get stuck in between.
The ECU will actually hold on to that cut
for a maximum amount of time, say one or two seconds,
to give the driver the opportunity to fix that.
In an open-loop system, you don't have that.
You need to, sort of, make sure that every shift
is correct and, you know, there's too many variables.
- So, essentially what you're getting
is the shortest possible cut time.
If you're using a timed cut and you really wanted
to get that shortest possible timed cut, you risk
having the engine power being reengaged while
the driver's still part-way through the shift.
Now, in terms of the shift times, just because I
know a lot of our viewers are interested in that,
how long does a typical shift take
in a gearbox like the Albins?
- So, with this Albins, we're seeing through the logging
that the average time that the ignition cut is active
is between 35 and 50 milliseconds,
depending on, like I said before, load RPM,
where the driver is on the track.
Yeah, so, roughly 40 milliseconds
I would say is probably the average.
- Now with a car that's making a lot of power,
like the 600 kilowatts, that's been pushed
quite hard, what, when the car comes back
into the pits and the dot is downloaded,
what are the essential aspects
that are being looked at first?
- So probably the first thing I will
look at on this particular car,
we have EGT sensors in each exhaust runner,
so that's probably the first thing
I'll look at is probably a max EGT from that session.
As long as they're, sort of, within our usual
numbers that we're used to seeing with the car
I'll go through and make sure there's been no
funny issues with the fuel system.
We're pretty much at the maximum for the fuel pump
in this car, so I'll go through and check
the injector pressure differential channel,
make sure that's not taking a dive anywhere,
and then, yeah, just basically check the trims,
make sure nothing is going crazy with the trims.
- So engine health is really your first priority.
Before you worry about anything else,
you're really looking to make sure that the engine
isn't exhibiting any real problems.
Just moving back to the car itself, R33
it's a heavy car compared to some
of the runners in the Open class.
How much of a problem is that, realistically?
- Yeah, look, I guess there are some guys
that run replacement panels and everything,
like carbon, to try and reduce the weight,
the 33GTR being the heaviest of the three.
Yeah, it takes a bit of a hit
in terms of pushing that car around.
Yeah, I think this car's still all metal, front to back,
yeah, the weight's, I don't think the weight is a problem
with the power, I think probably aero
takes a bigger hit on the power than weight does.
But, yeah, we were seeing the tyres just get
hammered here with the weight of the car.
But, yeah, big heavy girl but she gets around.
- There's one thing we're hearing with the compound
that's being used here at World Time Attack.
It really is a compound that is only good for one
or perhaps two laps, and on the heavier cars
we're hearing that that compound is a struggle
to maintain good tyre temperature for just one flying lap.
Look, Mitch, thank you for giving
us some insight on the car.
We've still got a couple of sessions to go.
The car's currently, I believe, running around about
the middle of the pack, so best of luck
for the team to improve.
Thanks for letting us know what makes it tick.
- Sweet, no worries, thank you.