- We've probably all seen videos on YouTube of spectacular diesel engine failures and
with some of these engines capable of producing 2000 horsepower, there's no
surprise that when they let go, they let go in a spectacular fashion.
Well in order to keep these engines together, more and more technology needs to be
applied in terms of the engine components and we're here with Drew from D&J
Precision Machining to find out a little bit about this custom billet block Cummins
diesel engine behind me.
So Drew for a start, this Cummins engine that you've developed behind me,
it's not quite dialled into its maximum performance but you're expecting the
ability to handle somewhere in the region of 3000 horsepower is that right?
- Yes yeah we're looking for somewhere between 3000 and 3500 horsepower.
That's about as far as our customers right now can handle with their chassis setups and
stuff like that.
Pretty sure we have the capabilities to go further than that if we need to in the
future with the platform that we have here but right now like I said the customers
just really can't use it.
- So let's start by talking about the factory Cummins block.
They're already capable of making pretty impressive power, at least for a street
truck in relatively stock form in terms of the components, where have you found
the failure points for the stock Cummins block?
- Yeah in the 1000 to 1200 horsepower range typically, maybe a little bit more than that
depending on torque base, we usually have problems with the blocks failing in the
cylinder walls.
So the first thing that we usually do is do a deck plate and a sleeve setup that
strengthens the cylinder walls in the block.
After that, we really can't get any more strength in the bottom end and we've
had engines that have blown apart right at the main web so there's some pretty
famous YouTube videos, it was actually one of our engines and that's what sparked
the development of this.
We really could not strengthen the factory block in that area anymore so we just decided
to redesign the whole thing.
So it starts with a 67 crankshaft because some of the rules that we have
to deal with in the tractor pulling says that the stock 67 or the stock Cummins
crankshaft has to be able turn in the engine.
So it's all based off a 67 Cummins platform but that's about the end of it, everything else
has been redesigned by us to maximise everything that we can and make it as
lightweight as possible.
- Now you say it has to have the stock crankshaft be able to turn in the block
so essentially what you're saying there is it has to maintain that stock
geometry for the crankshaft but it doesn't mean you have to retain a factory crankshaft?
- Correct yes this has a billet crankshaft so it's been redesigned, billet, better material,
but yes the bore spacing has to stay the same, the centres between bores,
all that has to stay the same.
- Now we've seen the sort of adoption of billet aluminium blocks particularly in
import drag racing where people were just getting well beyond the capabilities of
the stock cast iron blocks in the likes of the Toyota 2JZ.
Obviously that's the natural progression here in the diesel world as well.
I'm interested in finding out a little bit about the design strategy behind taking
what is essentially just a massive chunk of alloy billet and deciding on exactly what
design to use, where to put material et cetera and then validating it so you've got the
confidence that that engine will in fact be able to support 3000, 3500 horsepower.
- Right yeah so we can simulate a lot of these things in Solidworks.
So we can stress test the block, basically top to bottom for the block trying to blow apart
top to bottom and then decide where we can remove material, where we need to
add material, how we want to put gussets in.
So we settled on a steel bed plate setup and it's got six bolt mains with 5/8th
threads in the block to help take care of the foundation in the base.
And then we go to a ductile iron sleeve with a one inch taller deck height, one inch
longer connecting rod to help straighten out the rod angles.
- So that's to improve the rod to stroke ratio?
- Yeah exactly, rod to stroke ratio and straighten the connecting rod in the bore.
- I'm assuming you're also revving this a lot further than what a stock Cummins
was ever designed to?
- Yes we are revving, the stock Cummins is designed to run about 3500 RPM and we've
had these, we've had our cast engines at 8000 before.
- OK that's a massive difference.
Now you also mentioned a steel bed plate so can you just talk us through what
exactly that term means?
- Yeah so typically a block has a main cap right so main cap and it sets down on
the side of a saddle so we split the block basically at the parting line of the main
bearing and put a steel bed plate on the bottom so the whole base of the block
is a steel bed plate.
- So that just provides additional strength and better support?
- Right so much stronger, much better support.
- Now in terms of the Solidworks software you're talking about with the design here,
it's safe to assume you're talking about FEA analysis of the engine design?
- Right correct yeah, FEA analysis we can put loads in any different position that
we want, we can fill the intake plenum for instance with say 200 pounds of
boost pressure and see where the failure points of that are.
The customers in the drag racing world are really interested in lightweight
components so we set a goal for overall weight in the cylinder head and really we
only had like 10 pounds to work with with the intake manifold on this engine.
So it took us a lot of work just to get that to flow how we wanted it to do,
have the volume and plenum that we wanted to and also not blow apart.
- That's one of the key aspects.
Now one of the problems obviously in terms of running massive massive
cylinder pressures with a lot of boost, a lot of nitrous which we'll get onto
shortly, is maintaining good cylinder to block or head gasket integrity,
that seal there.
Is this an issue in the Cummins and if so how have you dealt with that?
- It is an issue with all engines, this is unique, we actually did the head gasket,
it doesn't have a head gasket, it's all o ring sealed for all the oil passages.
And then we are using a spring energised compression sealing ring to where we
can actually pull the cylinder head off, service anything we need to do,
put everything right back on, the spring energised C ring is reusable for all
its purposes, it's something that was developed with aerospace and NASA stuff.
- I believe they're used in the nuclear power generation industry for sealing?
- Yeah I think they are yes.
It's been very good for us so far.
Very resuable, very good, so if the customer has anything, we've had guys
blow turbos up for instance, pull their head off at the track, clean the pieces off and
go back to work.
- My understanding with those C shaped spring energised seals as well is that you've
essentially got the cylinder pressure going out into the seal and helping expand it
so essentially if the head lifts a thou or two which can be inevitable, that C spring can
basically expand out, maintaining that seal?
- Correct, that's exactly how it works.
It gives you some flexibility with the expansion and also the cylinder pressure loading.
We're actually testing cylinder pressure in this engine, it's the first time we've done
that, we can see the whole pumping loop and everything so we can see the intake,
the exhaust stroke, the whole nine yards.
- Safe to say for drag racing use, this is a dry block with no coolant in it?
- Yes this is a dry block application with drag racing and higher end sled pulling.
- Alright so moving onto the cylinder head because again you've got an engine that
in stock form was never designed to spin to 8000 RPM, never designed for
3000 plus horsepower and particularly getting that airflow at high RPM I can only
assume is a big challenge from that stock head so in terms of going to a billet
head there, does that flexibility help you, what changes have you made there and
how important is that billet head and maybe the cam in order to get airflow at high RPM?
- It's very important, with this cylinder head, we were able to, while stock head flows
about 165 CFM, this head flows 395.
And we also changed the port design on the exhaust side of this head.
We kind of ran into a wall with the way the exhaust ports exit in the stock
location so we ended up patenting this solution but we ended up splitting
the exhaust valves on the exhaust side so we could run each valve out of its own
port, it's a 24 valve cylinder head so we have 12 exhaust ports on this cylinder head.
- I did see that on the exhaust manifold and wondered what you were doing there.
So where's the pros and cons with that setup versus stock?
- Well we really haven't seen the end of it yet.
So the idea is to be able to get more exhaust flow and we can definitely see
that in the cylinder pressure data.
We were evacuating the cylinder very fast, now when we start turning the power
up, we were at like 1500 horsepower areas the last time we were testing,
when we start turning the power up and we have more exhaust mass,
hard to say exactly what's going to happen there.
But it's a big thing just trying to get rid of everything.
- Alright so talking about getting the airflow into that engine, so what's the turbo
setup that you're running?
- In this application we're running just a single GT55 98 mm.
We have other applications with sled pullers where we're running compounds,
triple turbos.
This application is drag racing and it's not been worth the weight to carry
the big turbos down the track.
So we're single turbo with nitrous and then we, a lot of times we'll run air to water
intercoolers, it's the best way to make power for sure but in this application
we're doing water injection and that again is the same reason, it's just for weight.
It has not been worth the extra power to make an air to water cooler go down
the track.
- So essentially sacrificing potentially maybe a little bit of power to reduce that weight and
your net result is an improved ET and mile an hour?
- Yeah well it doesn't really sacrifice the power, since we don't have any real
constraints in this application we can run nitrous, we can run whatever size
turbo we want, we can just run more nitrous or bigger turbocharger or anything
like that and still net the same power.
So it's not an as efficient way of making power obviously as an air to water intercooler would
be but at the end of the day it hasn't been worth the difference, we've still been
able to make as much power as we need to to get everything to do what it needs to do.
- Now I just want to come back to that turbo setup there because we do see a lot of
compound turbocharging used in the diesel tuning world.
Particularly for sled pulling et cetera.
And the single turbo on face value might be a small sacrifice in boost response and
also there you don't have the boost multiplication effect of a compound turbo
so you wouldn't be able to run for example on a single turbo generally maybe 200 psi
and still work in an efficient area of the compressor map.
So is it just the fact that you can run the nitrous to get around that to get the power
you want without needing massive boost pressure here?
- Not necessarily, we can run big single turbos, I mean we've run turbos up to
five inch diameter on these engines, they're 410 cubic inches.
Those turbos will make just as much power as most compound setups but like you said
it's the drivability.
So in certain applications like sled pulling they typically run compounds so they
can run a lower RPM and they have a wider powerband.
A big single turbo can make the same amount of power but a lot of times it's
just in a lot narrower power band.
- And for drag racing you can obviously work with that narrower power band plus
you've got the nitrous there to get the turbo up on boost initially?
- Right yeah we can use full jets, we can use different stages of nitrous at different
times down the track.
That's the key to drag racing at least from what we've found so far is power management.
You have to be able to apply the power when you need to and take it away when you need
to and that gives us lots of flexibility with the fuel system that's on this engine,
the nitrous, the whole nine yards.
- Alright so that's a good segway into that fuel system and the nitrous as well.
So starting with the nitrous there, you just mentioned stages and interestingly it
looks like you've got what is a conventional gasoline wet direct port setup but of course
injecting diesel through a wet nitrous system would be of no use so tell us how that works.
- Yeah we actually use a wet nitrous system but it's actually just two stages of nitrous
into the same nozzle.
- And then you mentioned spool valves as well so just talk us through how that works.
- Yeah well we have different spool jets that come on.
- Spool jets sorry.
- Yeah spool jets that come on at different times so when we're up against the torque
converter, once we see a certain fuel quantity, a certain EGT, one spool jet will turn on with
the ECU and then once we get to a little bit higher fuel quantity and a little higher EGT,
the second one will kick on.
And that's just to stage.
So once that happens, when we come off the button, the trans brake, another stage comes on
and then everything's timed out after that.
- Probably a good place to actually ask, what sort of ETs are you seeing from
these combinations?
And again obviously you haven't got this thing running at its full potential yet so
in your existing applications using cast blocks, how fast are you running?
- Yeah in our cast blocks we've been 4.25 at 177 mph in the 1/8 in a 3150 pound truck.
- And where are you expecting with all in, let's say 3000 horsepower, where would
you expect to get to?
- Hopefully this year if everything goes well, if we can get the chassis to cooperate,
we should be well into the threes this year.
- That's pretty serious no matter what fuel you're running on there.
So talking about that fuel system again, so we've talked about the nitrous,
obviously you've got to get the diesel fuel in there as well and a huge quantity of that.
And that can be problematic, can you talk us through the fuel system in terms
of the pumps and the injectors you're running?
- Yeah Exergy's helping us with our fuel system, so right now we start with a low
pressure pump that supplies about 15 psi of pressure to the CP3 pumps.
The CP3 pump's a high pressure pump, are feeding like a 500% over injector.
So 500% bigger than stock basically injector.
And that's all controlled with a Bosch ECU and Exergy performance is helping us with
all that stuff, Phil Devries has been just invaluable to this whole package.
- Alright Drew it's been great to get some insight into the project and not only is it
potentially going to make 3000 plus horsepower, it is an engineering work of art so we wish you
all the best once you get this back on the dyno in a week or so's time and look
forward to hearing your results.
Thanks for the chat there.
- Yeah yeah we're supposed to leave here and go right to the dyno so it should be fun.
- Hopefully it's not another one of those YouTube clips that you don't want out there.
- Yeah it happens, it's part of testing, hopefully not.
- OK thanks a lot.
- Thanks.
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