- Four wheel drive street cars like this Mitsubishi Evo behind me are becoming
more and more popular to take to the drag strip and we've seen the drag records fall over
the years.
However, one problem with a four wheel drive strategy is that getting the car to launch
consistently and reliably is incredibly tricky.
Obviously with all four wheels doing the driving, the problem is there's a lot of
traction there and particularly on a very sticky drag strip, this can be a problem.
We generally see a lot of four wheel drive drag cars, either bog in when the driver side
steps the clutch and go nowhere, or alternatively light up and wheel spin in
third but definitely the worst scenario is break some of the drivetrain components.
We're here with Joe from Team Karem Racing to find out a little bit about what makes
this Evo tick and particularly Joe, I want to start by talking about what I think is the
worst kept secret in four wheel drive drag racing, the clutch slipper.
Can you talk us through what a clutch slipper is?
- It is mate, it's probably the hardest thing to get out of the hole with a four wheel
drive car.
We run the Magnus slide on this car.
It does help dampen the car on the initial hit.
It's pretty much just riding the clutch out of the hole for you, that's the whole
idea of it.
- So let's go back a step, what we really want to do is we want to get the car moving
off the start line without the engine bogging and without it just lighting up into wheel
spin so it's a real fine line and some drivers have an uncanny knack of being able to
manually slip the clutch just the right amount but of course everything's happening
incredibly quickly and as the power levels step up and the grip levels step up,
this gets harder and harder to do so when we look at professional levels of drag racing
with the likes of pro stock we have what is referred to as a slider clutch which is
a special clutch designed to slip.
We can't fit one of these into the likes of an Evo so this is the next best thing.
So can you talk us through, you've talked about the Magnus Motorsport slipper valve
and how does that actually work, how does it install in the system
and what does it do?
- OK we've basically just t'd it between the clutch line so once you're ready to launch
the car, so first gear, clutch in, pretty much get your lights and drop the clutch and the
valve actually takes over.
- So the valve restricts the flow of that hydraulic fluid in the clutch system,
so it physically forces the clutch to slip off the line?
- That's it mate, that's exactly what it does, it just dampens that initial load and just
brings the pedal back up slowly so it doesn't actually just bond the tyres
or bog or whatever and whatnot yeah.
- Now one of the problems of course when you're doing this is you're forcing the clutch
to slip so you need a clutch in there that's capable of handling the torque the
engine's producing but also is able to withstand the heat that slipping produces so what have
you got in there for a clutch.
- I'm running the direct twin plate clutch on it.
Instead of the brass plates we're running iron plates in it.
So it does take a bit more of a belting but you do take life out of it either way.
- On some of our cars running the same sort of system, we're running triple plate
clutches and getting 10 passes out of a set of clutch plates so it's pretty brutal on the
clutch but that's the price you pay for consistent 60 foots.
So what sort of life are you expecting out of this clutch?
- If we can get 20 runs out of it, out of a good hard 60, and 60 foot I'm talking maybe
1.2, 1.3 60 in it, it's a good life out of that clutch.
- I think as well, just for those who are watching this who really aren't familiar
with drag racing, the 60 foot, that's kind of, in drag racing world that's the measure of
how well the car is getting out of the hole, how well it's launching and it's a rough
rule of thumb that gaining a 10th of a second at the 60 is basically worth
2/10ths at the end of the strip.
So that's the place we really want to focus our efforts, getting the car to 60 foot
really quickly and that's going to make your job in terms of getting a quick ET just
so much easier.
We've looked at the clutch system here but of course there's a whole car around it
so let's go back a little bit and talk about what you've done here.
So we can start with the engine combination, what are you running here?
- It's a 2.2 stroker engine, 4G63.
Cast block steel.
Pretty much, it's still streetable the car, the car drives all day every day no problem.
It makes about 650 kWh on this 3584.
We do have a bigger turbo going on in the near future.
- I just want to go back to that as well because this turbo, for an all out drag
application is still what we consider relatively small but you're kind of building
up on this aren't you, you're getting everything sorted on the smaller turbo and it's still
1000 horsepower turbo so it's no slouch but for drag racing, that's going to limit
the ET so then you're going to step up?
- Definitely not a slouch man, it still pumps, still goes very well.
Still early days, the driver's still getting used to the whole concept of drag racing,
shifting gears, using the sequential box, just getting his head around really the
whole car.
Once he's comfortable, we'll give him more as he goes.
- Over the last few years in particular we've seen more and more competitors move
to billet blocks, these have sort of become the go to and definitely if you're up at
the 2000 plus horsepower level they tend to become essential.
At the power levels you're expecting with this, cast is still fine?
- Cast is fine, we've pushed others in the future well over 1000 horsepower at
the wheels and I've never had an issue so far so keep pushing it 'til we do.
- One of the big problems with any high boost turbo engine and in my own
experience, the 4G63's certainly no different is head gasket integrity is key and what I
mean by this is we can make as much power as we want provided we've got turbo in there
but at some point the cylinder pressure tends to actually physically lift the cylinder
head off the block and allowing the combustion pressure to leak out into the cooling system
so how are you addressing that?
- Just with a copper head gasket and fire rings and they just crush against the head.
- So the fire rings, there's a variety of options there and materials and things
that people refer to as fire rings, can you get a little more specific on what you're
running?
- Yeah what are they called?
- Aluminium bronze?
- Aluminium bronze.
- So this has been something we've seen the likes of the pro line drag engines run as well.
- Pretty basic, pretty straightforward, it works, half inch head studs,
pretty basic stuff.
- When it comes to building a 4G63, there's a lot of options these days
and there have been for a while, there's two litre, 2.1, 2.4, 2.2, you can use the 63
in the 64 block which have a different deck height, a different bore diameter.
Can you give us a rundown on why you've chosen the 63 block and 2.2 stroker kit?
Where do you see the advantages and maybe disadvantages of that setup?
- I like to keep it with the 63 block.
Reason being bore size as well, keep the bore a bit tighter.
The 64 I just find that it's starting off at 86 mm, this one's starting out at 85,
just a bit more integrity in the block.
And I find that it makes just the same amount of power if not more.
- Yeah I think there's the old story that there's no replacement for displacement but
there's some truth in that but when you're running a turbocharger you can actually make
up for a lot of displacement with a couple more psi of boost and you're right, the 64 block,
particularly if you go to an oversize on that, you're ending up with a lot less material,
particularly between cylinders and a thinner sleeve so yeah I think that makes a lot
of sense.
Alright talk us through the fuel system on the engine because I've noticed already you've
got a mechanical fuel pump running off the front of the exhaust cam so where's the pros
and cons of mechanical versus electric?
With the mechanical, obviously there's no voltage drop, no current issues,
no power issues, it's just mechanical, engine runs it.
That's what we find, running three and four fuel pumps to run these cars,
it's becoming ridiculous.
Your alternator can't keep up, you're running a dash, you're running all these electrical
items in the car and there's just too much power going on through the car so we
found that the mechanical system, it runs more efficiently, the voltage is
where you want it all the time, it backs it up back to back, if there's a voltage drop
you lose fuel pressure, none of that, so that goes all out the window and
the car's consistent.
- One of the problems with a mechanical fuel pump is we see that particularly when
you're trying to start the car at cranking speed they're not really operating fast
enough to build up fuel pressure, so how are you dealing with that,
have you got an electric primer pump as well?
- Yeah we're running an 044 Bosch just with a one way valve.
So basically the FuelTech controls it just on the crank.
So once you actually crank the car, the pump works and then once it actually sees
RPM it turns off and the mechanical takes over.
- We haven't actually touched on the type of fuel you're running, so let us know what
you're doing there.
- It's on E85.
- Is there a reason you've gone E85 here rather than maybe stepping up to something
like methanol?
- Methanol is definitely on the cards, right now for where we're at I think E85's a good
starting point and then definitely going to methanol.
- With methanol, one of the problems is over pump gas we need to run somewhere in the
region of maybe 40% more fuel volume compared to pump gasoline in order to make the same
sort of power so that obviously puts demands on the fuel system.
You've addressed that with the fuel pump, talk us through the injectors, what are
you running there?
- I'm running Siemens 2400s.
There's two row on it now however it's only using the one on E85.
Once it's ready for meth, the injectors are ready to go.
- And you'll run those through the FuelTech ECU in a staged manner, so just one set
at idle, low RPM, low load et cetera and then bring the other ones in?
- That's it, stage them in.
Once you see 10 pounds, bring the next set in and go from there.
- Alright so you've mentioned the FuelTech ECU so let's dive into that a little bit,
you've got that FuelTech ECU running the whole package.
And where do you see some of the advantages of that FuelTech ECU, I know that it's become
very very popular in the US, we haven't seen it so much in maybe Australia
and New Zealand just yet, starting to take off a little bit.
- We just found the FuelTech, the datalogging is on point.
Just basic logging of the car and just in depth as well, you can get in there and just,
the O2 closed loop control is phenomenal.
The lambda control is crazy, works perfect all the time, backs it up, where some other
ECUs do tend to not give you the right reading where you really need it in the
critical stages.
- I think another thing that I hear from a lot of the teams with the full tube frame cars
that are running FuelTech is the advantage of being able to control everything
from one box rather than a lot of people run a separate boost controller, a separate maybe
ignition controller, you can do everything in one box with the FuelTech?
- Yeah it does need a nano box, it does need a peak and hold box to control the
injectors but pretty much the unit is the dash as well.
So that's a bonus, so you don't. have to run too many boxes, too many dash and
CAN cables and whatnot to run everything, it's all into the dash itself so dash is
computer.
It all works off the dash, it's all touchscreen as well.
- That's actually a nice feature as well because often as the track conditions change
during the day you might find yourself in the staging lanes and maybe there's
an oil down or the weather conditions change and maybe the track hasn't quite got the
grip so rather than running for the laptop you can actually make subtle changes to
maybe your launch strategy straight from the dash?
- Yeah correct you can adjust it all from the dash, it's got five different maps.
You can change, for one you've got a setting for lower boost or different fuel
or whatnot you might want to run.
- Now in terms of boost control, that's another real key one.
We've talked about getting a four wheel drive car to initially get off the line but a lot of
this also comes down to torque management which of course can be controlled with the
boost pressure.
So can you talk us through how you're controlling boost?
- This car runs a CO2 system.
It's integrated within the FuelTech so the FuelTech manages the boost controller
on it so right now it's set over speed.
So it's got a clutch switch, so once you drop the clutch the timer actually starts
clicking and starts counting so just after the 60, so 1.5 seconds say, we dump all the
boost back into it and bring it all in.
- So you're dropping that boost out through first gear to just get the car to hook up
initially and then driving the boost back in?
- Yep correct.
- Alright so again for our viewers who maybe aren't quite familiar with that term CO2
boost control, normally we run a conventional boost control system where the boost solenoid
is supplying just the boost pressure from a charge pipe to the wastegate so how does
CO2 differ and where are the advantages?
- CO2 is just basically a bottle filled with CO2 gas, it's compressed, it's pressurised,
so the advantages are that the wastegate shuts instantly.
There's no lag between waiting for manifold pressure or boost pressure to build up.
Once the gate is shut, boost is up, it's gone, it's full, it's ready to go.
- Now I think as well with that, the CO2 is at a much higher pressure,
regulated to a much higher pressure than what the boost pressure might be,
maybe you're running the CO2 at 80 psi.
So particularly I've found with four wheel drive drag cars, you need often,
once you've probably stepped this up as well, quite a wide range between the boost
that you'll leave the line in in first gear and what you'll run in the deep end,
maybe fourth and fifth gear so that gives you that flexibility which you might not
have with just normal boost control.
Now talking about the rest of the drive train, that's obviously another key potential
weakness for any four wheel drive drag car so what are you running there?
- This one runs a five speed Samsonas sequential gearbox.
Still running the ACD transfercase.
- So that's the active centre differential for those not familiar with Mitsubishi.
- Correct.
In the rear we're running a GTR R32 diff.
We've made the conversion for it to fit into the Evos.
That's pretty much it, it's pretty straightforward.
- And was that because you were breaking the factory differentials or some other
advantage with the R32?
- Just knowing where the car's going to go and what we're going to do with it.
We're ready to go, so we don't want to wait for breakages.
It's good to go straight away.
- Look from what you told me before in a previous build, much simpler than
it is now, the car's already run a 10.50 at 150 mile an hour.
Obviously just scraping the surface and as you said you've got a smaller turbo
on it right now just while the driver's getting up to speed and you're getting the package
sorted but certainly it's a beautiful build, it's a credit to all involved and we look
forward to seeing what the car can do, particularly once you step up the power.
Thanks for the chat.
- Cheers mate, thank you.
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