- When it comes to open class competitors at World Time Attack Challenge, there's no
shortage of high end builds however one clear standout for us is
the Dream Projects S15.
We're here with Charles, owner and builder of this S15 to find out what makes it tick.
So for a start Charles, let's just talk about World Time Attack Challenge in general.
And over the years we've been coming here, we've seen two things really dominate,
power and aero.
You've definitely got aero and we'll get into that but interestingly here you've gone
with the SR20 based engine and a lot of the competitors in the S chassis will go with
an RB30, RB26 so more capacity, more cylinders.
Can you tell us what drove you to stick to the SR20?
- Yeah so I mean we just wanted to keep it low, keep the balance where we want
it to be, the motor's, the four cylinder's perfect for this chassis.
Putting in a 2J or an RB just wouldn't be right, it wouldn't fit well, there's so many
other compromises that come from that with your cooling systems and things
like that, the flow on.
And also just sticking close to Murray, the guys involved.
In this car, obviously involved in the Hammerhead and all the Queensland...
- So you're talking Murray Coote there, builder and owner of the Hammerhead
just to give some reference there.
- Yeah correct yeah, Murray Coote.
So yeah, very happy with the little four cylinder there and it's, power wise it
does everything we need it to do.
- Alright so one of the things there, basically you're saying, your focus there
has not been on outright power, you're looking for a well balanced lightweight
chassis and the advantage with that four cylinder over an RB or a 2JZ is it's a
lot shorter and a lot lighter.
On top of that though, we can see you've also moved the engine back a long way
in the chassis so can you tell us what the rules allow there and have you exploited
that to the absolute maximum?
- This car is obviously built to the current rules, to the maximum.
51 millimetres is the amount we can move an engine back in open class and that's
exactly where it's at basically.
So we've got to take advantage of everything.
If we leave anything out, any margin out there, we could be beaten by the next car.
So we've got to take advantage of every opportunity we can.
That's the beauty of starting with a build from scratch is you can do all that stuff.
- Alright so we've talked about the fact you've gone with the SR instead of the bigger
capacity engine but it's still no slouch, how much power is it producing
at the moment?
- Yeah so it's a little stout 2.2 litre stroked SR20, little VE cylinder head.
So I mean that's 900 horsepower at 34 pounds of boost.
At this point we're sort of running out of turbo but I mean 900 horsepower,
when I got the brief for the build, 800 horsepower was what I was asked to
supply and we're well and truly over that.
Horsepower isn't everything, obviously it helps but we've got a very happy balance
so we'll see how we go.
- Now getting into that, getting a reliable 900 wheel horsepower out of an SR20
is no mean feat, even if you're going to a 2.2 stroker kit.
So billet block here, can you tell us about the componentry inside the engine that you're
using to keep that reliable?
- Yeah so first thing we did is got in touch with the top guys in Australia
and Peter Mcdonnell from PMC Race Engines.
I've dealt with him for a long time back in my first car, my Datsun and had an
RB in there and the first thing we built on this car was the motor.
We started building a motor and then the car came together after that.
So we've got a P12 V cylinder head with some Kelford cams and we've got
a NItto 2.2 litre stroker kit with some CP pistons.
Look fairly simple to be honest, there's nothing too outlandish.
At this point we haven't really had an issue with anything and it's been the most reliable
part of the car, it's unbelievable.
- Off camera before you were saying that so far it's been running at that sort of
power level and I think you said you'd done in excess of 100 laps with no
reliability problems?
- Yeah obviously not all hot laps but we've been circulating, we've done four tests
in Queensland Raceway and then here as well and we haven't put a spanner
on the car and that's a tribute to the preparation of the car.
The GT Auto Garage boys have just gone above and beyond, with their attention to
detail and yeah it's been a real dream run for us.
- Of course it's worth mentioning here that the billet blocks, at the pointy end these
engines are really designed around power levels, 1500 and well above so you're
ultimately not stressing them that much but circuit racing versus drag racing
is a very different amount of stress on the engine.
Now you just mentioned before that you were essentially out of turbocharger,
can you tell us what the turbo on the engine is?
- Yeah so it's our BorgWarner EFR 9174 with a 1.05 rear housing I think.
So yeah just running out of puff, it's just getting harder to make boost after
34 pounds so there's no point in trying to stress the limit on that and keep it in the
happy space and that's sort of where it's at and yeah for us the power,
that's, we've got more than enough.
- Those EFR turbos as well, well known that they do have a maximum RPM above which
you do risk the turbo basically falling to pieces.
Are you monitoring turbo speed and if so, how close are you to that maximum speed?
- Yes we are monitoring the turbo speed, we've got a little sensor on the front of the
BorgWarner, it's controlled through the MoTeC and yeah I think we're still quite,
I think a little bit under.
And that's the biggest, one of the parts of the decision making process for the 9174 is
'cause of that turbo wheel speed and these little SRs on high boost really do run 'em hard
so the 9174 was a better option, there is other, obviously the 9180 the bigger turbo
but that 9174 can spin a bit harder than that turbo so that was the choice.
- OK now moving on through the drive train, what's the transmission you've got backing
up that engine?
- Yeah so we've got a Holinger RD6 sequential with the strain gauge dog.
So that's perfectly suited for this car.
- So that strain gauge gear knob feeds into the ECU, allowing the driver for clutchless
upshifts?
- Correct, that's correct.
- And that's pretty important as well with these big turbos on relatively small engines,
keeping the turbo on full boost during the shift?
- Yes exactly right, and downshift it's rev matching and things like that so it's just
really really nice for the driver.
- So that rev matching is that automatically done through the ECU and a drive by wire
throttle as well?
- Yes correct, that is right.
- So allowing the driver there to concentrate solely on getting maximum braking
performance?
- Exactly yeah he can take time on the clutch, not have to worry about too much and really
focus on that braking.
- Alright so can we talk just briefly here about the electronics package, what have you got
controlling the engine and the rest of the electronics in the car?
- Yep so we've got a MoTeC M150 ECU, it's controlled through a PDM30.
And obviously all the little bits and pieces that go along with that.
Obviously a custom motorsport wiring loom for the whole car, we've got quite a few
sensors, not more than we need but we've got shock potentiometers on all the corners
and wheel speed sensors and all that sort of stuff to get that vital data that you need
to put down a quick lap.
- Now for those who aren't familiar with the terminology there, you mentioned the
MoTeC PDM so power distribution module, just a unit there, essentially solid state
electronics that gets rid of fuses and relays, great for reliability and I notice you've got
that keypad controlling all of those functions on the dash?
- Yes yes it's got the keypad there.
So that was the biggest thing for us is you get the right parts once,
minimise fuses blowing and things like that, the PDM is just perfect and it's the right
technology to use and it just makes life so much easier.
- And you've got the MoTeC C127 in there as a driver display, you're also using that as
a central logging hub?
- Yep got the logging through that and the driver display so it's easy to read,
keeps everything in there and gives the driver any warnings, any feedback if there's
anything going wrong.
- Now again, in terms, we've already mentioned the fact you're aiming for a
lightweight car that's well balanced and part of that is getting the weight as close to the
centreline of the car as you can.
And is that the driver there behind the location of the fuel tank, the fuel cell
as well as the dry sump tank?
- Yes so obviously everything about this car has been a decision, there's been no
guessing, everything that's put in there is put in that spot for a reason.
CFG, all that sort of thing, offsetting the driver weight.
- So that gets onto obviously Barry Lock, the engineer designing the entire car
from start to finish.
Every part of it, there's a drawing for it so that's where it's at.
- Now again for our international viewers, Barry Lock is a pretty big name here in
Australian motorsport but of course our international viewers, probably got no idea
who he is but also instrumental with the design of the MCA Hammerhead which
is probably one of the fastest cars here, particularly in the pro class.
So let's just talk about some of the elements that Barry has designed for the car
and how that's come to be and of course you can't really look over the aero on the car,
again I mentioned it at the start, it becomes such a big part of
World Time Attack Challenge.
So can you talk about that aero package, how that was developed and what it's
providing in terms of downforce?
- Yeah so I supposed we obviously, early stages got in touch with Barry.
And Barry took control of, freedom with his pen and paper, pencil and paper and started
with the chassis setup and chassis design and then obviously moving onto that
aero design.
This car was sort of built over a couple of years, it was obviously developing as
we got to the next stage so it wasn't all just done first and then made later,
it was sort of, OK let's get the front end sorted, let's get the rear end sorted,
OK well now that's done, let's move onto the aero or the uprights or wherever
we needed to go.
- I think that's something that so many people overlook as well, it's a lot of money goes into
building a car at this level, even at a grass roots level it's still a lot of money.
But you can save yourself so much money if you start from the beginning with a
complete picture of the finished car and only build things once rather than
going through and modifying things time and time again.
So that's a pretty smart way of doing it.
Now I just want to talk about the suspension because they're having some pretty big
changes there, still running MacPherson strut at the front but there is a custom upright
that you just alluded to.
Can you tell us what the advantages of that upright are over the stock hub?
- Yeah it just gives you superior geometry, options, anti dive, all that sort of stuff
that you just can't get with a standard upright.
Obviously weight's there as well, there's a weight issue that you can overcome
and just basically to get the geometry where it needs to be optimal for,
what we can get with a MacPherson strut.
- So in terms of the geometry there, obviously there's your camber, your caster, your toe
but sort of more subtle things like the ability to I assume that you can adjust your roll
centre height as well as the likes of your bump steer?
- Yeah all the low hanging fruit we can get a handle on and that gives you that little
edge and that was the decision process to go down that path.
- Alright so moving to the rear of the car, the S chassis's had a lot of development
and most guys are running the standard multi link rear end with the Nissan sub
frame but you've gone a little bit above and beyond there, can you tell us what
you've done there?
- Yeah so it's got a double wishbone rear end, obviously into a subframe that bolts into
the standard pickup points on the S chassis so that was a lot of work in that to get that
worked out and make sure everything clears on full bump and all that sort of stuff
but that was a major component of the car, it helps massively with obviously your
geometry and power down grip, that's probably one of the biggest advantages.
When you're running upward of 900 horsepower at the tyres you really need
that grip to be superior and it's just hard to achieve that with the standard bolt
on kit application with S chassis.
- Yeah you're always going to be compromised when you're dealing with
a production car suspension setup, never really designed for going around
Eastern Creek in the 1:20 vicinity.
Alright so moving onto that aero package, so obviously again you've mentioned,
designed by Barry Lock there.
Have you got some sort of idea on numbers of what sort of downforce it is producing?
- Yeah so downforce, we're around 1000 kilo mark at optimal downforce so that's quite
substantial.
- What sort of speed is it producing that?
- 180 kilometres an hour is like the speed that that's all calculated on.
So plenty of downforce, obviously need to push that along as well so that's been a little
bit of a challenge.
Yesterday on low boost we got fifth gear and it just wouldn't go any faster.
So I needed to put the boost up and just to be able to pull another gear.
- That is always that trade off the downforce is great but often with downforce comes
a lot more drag.
So we're seeing a lot of these pro cars, their terminal speed down the end of the
front straight may not be as high as you'd expect given the power but the ability
to actually hold that speed straight through turn one is really where the advantage is.
Now you haven't actually mentioned the weight of the car so far, where's that sitting?
- We're just under 1100 kilos, somewhere there, with liquids in it.
So it's a little bit heavy but it's, there's a bit of room there for some improvements
but we've still got some glass in the car and we've got metal roofs and things
like those, most of the panels aren't carbon and some fibre glass panels there.
So there is some stuff we can do but you know just with the nature of getting a
build together and the last a few months before an event, you've got to sort of make
some little compromises and something we can work on.
- Now in terms of the class you're running in, the open class, there are some rules around
the aero that limit you compared to those running in pro or pro am.
Can you tell us where those sort of differences lie and particularly you're
talking here about what you've done with the underbody.
- Yeah so you've got obviously three boxes that you can work within in the open class,
just like any other class.
So obviously the open class is limited to widths and lengths and things like that.
So we just have to work in with that and just make the maximum advantage of what we
can do and I think that's where we're sort of at.
- Look you've done a 1:29 yesterday in practice on a car that at that point
had some handling issues that you've now worked through.
We're into competition day here on Saturday and we wish you all the best for the rest
of the event, looking forward to seeing what the car can do, particularly with a little bit
more development.
But thanks for the chat there.
- Very good, thank you very much, cheers Andre.
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