- When it comes to import performance, there's no doubt that the Honda and Acura
brand are in a league of their own.
Particularly in terms of the cylinder head flow, it's hard to beat even a stock Honda
cylinder head.
We're here with Luke from 4 Piston Racing.
4 Piston Racing are no strangers to the Honda brand.
Being involved with Honda engines at all levels of motorsport,
in particular their engines or cylinder heads are involved with setting
records in the sport front wheel drive class.
In particular their current record sits at a 7.93 at 189 mile an hour.
Now Luke getting that sort of performance out of a stock B series engine is
obviously going to be challenging.
You're also involved with the K series engines.
Now I wanna start by talking about one of the products we've seen on your stand
which is the billet CNC machined cylinder head for the K series.
Now in its own right the stock K series cylinder head is no slouch.
So where is the requirement to jump across to a full billet cylinder head?
- A lot of the all motor racing is alcohol, and we're getting to the point where
we just need to run more RPM and we're out of air flow.
So we're trying to squeeze big valves in there, and port sizing for those valves.
They were having trouble fitting in the stock castings.
We were running into water, it's getting hard to machine,
the head castings were getting older.
A lot of junkyard stuff and some of the heads are out of production.
So the heads that we could fit big ports in are kind of going away.
So we need to get more air flow, more valve, and we need to be able
to put the camshafts in a position that worked with those big valves so that
we can get the valve timing correct.
- Now that's a good point you've just touched on there.
In terms of fitting larger valves, I mean in the general off the shelf sport
compact market, it's pretty typical to take a one mil oversized valve from the likes
of maybe Ferrea and generally those can be fitted in on the stock valve
seats but of course there's a limit before you run out of valve seat or you have
problems with valve to valve contact.
So what have you done in the cylinder head to get around that?
- So we've changed the valve angle to be able to fit a five millimetre oversize
valve on the intake side.
We're still, and then we were able to straighten and change the shape of
the exhaust port.
We're still using the standard size exhaust valve but in the past we were even
shrinking those down to put bigger intake valves in.
But because we were able to move the valve angle, now we have better
separation and we can get our camshafts back where they need to be.
But we also were able to straighten those port walls out and get a lot better exhaust
flow, 40 CFM increase over the factory exhaust port orientation.
- Now in terms of changing the valve angle, obviously that's starting to
get into the realms of a major modification to some of the factory geometry,
and again really obviously stuff that just can't be done with a factory head.
Now in terms of changing that valve angle or moving the valve centres,
does that also necessitate you moving the location of the cams in the
cylinder head?
- Right now we're able to work with the factory location of the cam.
We can move it depending on how much change.
But right now only a couple of degrees of change is giving us a lot of flexibility
on the cam position.
So we are able to change the rocker arm more so than the cam location
and get it where we need it to be.
- Now in terms of making these modifications to the port shape,
the combustion chamber shape as well as the location of the valves,
you're in the realms of basiclaly infinite potential opportunities.
Are you modelling this before you actually put a piece of billet in the CNC machine
and start making your head or is this a literal case of trial and error?
- This is years on enlightened trial and error, what I call it.
So we have a lot of experience with what to do, what is working, what doesn't work.
And so we're pretty well guided on what we want to do without going into
modelling, we can probably most of the time, some of our ports are
designed in computer programs.
Most of them start from a hand pour and somebody sitting in front of a
flow bench or even a wet bench for many many hours, for 100s of hours,
to come up with this, over a long period of time.
We've been working with these K series engines probably since 2003.
So it's just years of experience and knowing what we wanna try and then sometimes
it's failing at it and trying to figure out what doesn't work.
- I think that's a good point to make there in so much as the cylinder head porting
is certainly not something that I delve into, I like to leave that to the professionals.
But this is one of the areas that I'd sort of say that there's definitely a lot of
science behind it but there is a lot of art behind it as well and I think this
is one area where you really do need to work with someone who has a lot of
experience with that particular cylinder head you're working with.
Otherwise you can take what is a stock good flowing cylinder head and do
something wrong with the port work and you can destroy it, would that be fair?
- Yeah that's fair.
And we set up guidelines and a set of rules that as we've learned,
these are the things we know that we need to be staying within this set
of rules and we know not to try some of the crazy things that are pretty
out there.
- In terms of fitting such a big valve into the K series block,
do you have problems with the valve location in relation to the actual bore,
'cause I think that's probably something that a lot of people would overlook,
but that obviously can become an issue?
- Yeah it can be and in the early stages of the development of this we kind
of had the valves moved too far and got into the bore and we still ran 'em like
that with success and we've gone back and moved things around a little more,
that's part of the trial and error thing, and deshrouded the valve a little bit
more but even with the valve shrouded up by the bore it still outperformed
everything we could do in the stock casting by leaps and bounds.
- One of the focuses with head porting as well is sort of getting a nice smooth
shape on that short turn radius getting that air flow to really turn around there
and go down through the valve.
So a lot of people with a billet head have gone to the point of raising the
intake ports in particular to get a straighter shot at the valve.
Is that important or is that not a necessity for you?
- It is and we do have limitations on raising the port, but we do have a
specific port shape that we're after that may not be as tall as what you'd
probably expect to see in a billet cylinder head.
But it again goes back to trial and error and what we have found to work,
and what works in the RPM range that we're working with.
And what we do on a two litre road race engine with regards to air speed,
and what we do on a 2.7 litre alcohol engine is very different.
A lot of times on these four valve cylinder heads, we're trying to slow air
down to round the short turn and make sure that we're not creating much
turbulence and if we can slow some of that air down in certain areas and
speed it up in other areas, we want a good even flow throughout the port.
If you measure air speed in one part of a stock port, you'll find other areas
of the port that are really slow going air and if we can kind of get that
to where we want it in every part of the port, that's what's gonna work best
for us, and we have a target number that we're looking for.
- In terms of RPM, you've just mentioned there, what sort of RPM are you running
these engines to and what is the usable RPM range in, let's talk here about
maybe a drag application, something pretty extreme.
- In a drag application, we're gonna be leaving the line somewhere between
7000 and 7800 RPM depending on the condition of the track.
And it's gonna drop down into the high sixes so we've gotta have some kind
of mid range power to pull it back up, but then on gear changes we're not
gonna drop below 8300 RPM, we're gonna run rom 8300 to 11200 and we want to
extend that power band as far as we can.
We're limited on displacement so we want more RPM, as much as we can.
So that's where we've gotten into needing bigger ports and bigger camshafts
and really stretching that out but we do have to have some low end responsiveness
where it's responsive as soon as we drop that clutch and it has to pull the car
through a good track.
- Now the other thing with the sport front wheel drive class as well,
you are limited to the turbocharger.
So everyone's running essentially the same size turbocharger.
So is this where maximising the air flow through those ports as well as your
cma profile really comes into its own?
- Yeah and valve timing's very important in sport front wheel drive and making
sure that the cylinder head is responsive, it's not just about going in and having
a great big port that flows a lot of CFM.
We really run into port sizing becoming critical on the turbo cars even more so,
because we've gotta stay in the efficiency range of that turbocharger and when we're
on gear changes, we're not allowed to have sequentials but we do have strain
gauges with, no one's clutching these cars.
They're shifted pretty quickly but the responsiveness and keeping it in
full boost, keeping this thing above 60 pounds of boost, the whole way down
the track is the key.
So I think that's where we've found some advantages is that our cylinder heads
are a little more responsive and keep in the meat of the powerband.
The whole way we have the most average horsepower going down the whole track.
- I think a lot of people when they're looking at flow numbers off a flow bench,
think that more is more but really that is only part of the whole story when it
comes to how that head's gonna perform when you actually put it onto the dyno?
- It is, true, and it's hard to look at, people look at a flow chart and it looks
a lot like a dyno chart and they think that it's gonna correlate and sometimes
it doesn't, many times it doesn't, it's not a dyno chart.
So when you're looking at losing, sometimes you may lose low lift
flow or gain low lift flow and it doesn't matter too much.
It may have lost there and gained up top and performed outstanding,
depending on what you're doing.
So you have to design it for the cam profile, for the induction,
it's a whole system that has to work together.
- Now back onto the billet cylinder head, the other aspect there with the billet
cylinder head, you are literally starting with a solid block of alloy and it's got
no water jacket in it.
So this obviously isn't gonna be suitable for your daily driver but for drag
applications running on methanol, the cooling isn't so much of an issue.
Can you talk to us a little bit about that and does that billet cylinder head with
no water jacket also improve the ability to seal the head to the block?
- It does for sure, it's not moving around as much, it's not as temperamental,
the temperature change, so we don't need to cool.
Even when we're not on methanol, even when we're on our class mandated
turbo fuel which is C85, VPC85, we still don't have a problem controlling
the temperature.
We're still running water through the block but it's helping quite a bit in sealing the
head gaskets.
And just keeping things from moving around.
But we actually have trouble getting heat into it and so we'll idle 'em a little bit
longer to get the block heated up and then run down the track.
This size of cylinder head is not really suited for other types of racing,
so we're not gonna have this on a road race car.
It's way too big of a port, it's way too agressive, it would be a dog.
So I know a lot of people have looked at the billet and said I want that
on my car, oh there's no water jackets, I can't have that on my road race car.
It would be a dog on the road race car, this is for high RPM extremely
high horsepower.
The engines that these are going onto make over 500 horsepower
naturally aspirated at 11000 RPM.
It's not gonna work in our circuit two litre road race car.
- Yeah I think that's another aspect a lot of people think that it's a one size
fits all but really you do actually have to design and develop the entire engine
for a particular application if you want to get the best results out of that engine.
Now just talking about the block, we've obviously focused on the
head there, and as is common with most import engines or a lot of engines
these days that are coming out, the block in the Honda, both the
B series and the K series is alloy.
Not an issue obviously in stock form but particularly in high boost
applications, this becomes a weak point so how are you addressing the block strength?
You don't see the need to go billet there?
- On the K series right now there's not, there aren't blocks cracking.
Even with huge turbos over 80 millimetres making more than 1500 horsepower,
the blocks are holding together.
The B series, some guys have found limitations.
You guys are all probably very familiar with Speed Factory, they run more than
100 pounds of boost on their B series and the are running billet blocks.
And that's because with that kind of boost pressure, cylinder pressure,
they have found the limitations of the stock block.
The K series not so much yet but there's also not a lot of people pushing
the limits like that at 2000 horsepower.
And so there will be a market for billet blocks and it's just gonna be guys finding
that limit and pushing over 2000 horsepower with these little four cylinders.
A lot of the class racing you're looking at more in the 1300 to 1400 horsepower
range, there's not a lot of issue with splitting blocks.
A lot of the tune ups are really good, a lot of the tuners are getting better,
the computers are better now, so it's easier for guys to monitor
the critical parameters that are gonna keep these things alive.
- So at that point, in the 1300, 1400, 1500 horsepower vicinity,
a good set of ductile iron sleeves is sufficient?
- Absolutely yeah and not all sleeves are created equal, some of 'em move around
more, some of 'em are softer, some of 'em have more support in the block.
So we try to stick with a sleeve that's got a lot of meat to it.
And that may work great in this drag race application but might have cooling
effects for an endurance application so we have to pick the sleeve that's
gonna be suited for that particular type of racing, it may be a really thick
rigid sleeve for drag race and 65 pounds of boost.
But in something that's gonna be 30 pounds of boost and run in a time attack,
or maybe even a 24 hour endurance race, we might have to give up some of that
sleeve structure in order for better cooling.
- OK so I think one of the other issues we often see when people go to an
aftermarket ductile iron sleeve is that they do that to fix the bore strength,
which is great, but a lot of the time we also see that that brings in a brand
new problem which is the sleeves dropping in use and then the head gasket leaking.
And this is a common theme we hear across a lot of people using these sleeves.
So can you talk to us about that and how do you fix that, why is this a problem
we hear about?
- It is installation related.
So if you have a good process and you are good with your machine and you
have a good operator, and you're doing things right and installing the sleeve
properly where they don't move around and you let them set,
and get them into position, they're not gonna drop, you're not gonna
drop a sleeve.
So you can do thousands of blocks and never have a dropped sleeve,
if the installation process is done right.
- So basically have the right equipment and read the instructions?
- Yes read the instructions.
No one wants to read the instructions, everyone throws those away,
and tries it on their own right?
- That's pretty important when you're talking about a finished engine that's
gonna run out to thousands and thousands of dollars.
Look Luke it's been great to get some insight into your engine components.
If someone wants to get in touch with you, how can they reach out?
- 4piston.com and we are on Instagram, @4pistoncylinderheads,
and Facebook at 4 Piston.
- That's great, Luke thanks for your time.
- Thank you.
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