- When it comes to reliability of any performance or racing engine,
making sure that the lubrication system remains reliable is essential if the
crankshaft and bearings have any chance of leading a long and healthy life.
And when it comes to the top shelf of lubrication systems, this of course is a
dry sump system where the oil is literally evacuated out of the sump,
stored in a remote reservoir and then pumped back through the engine.
This ensures that there's always a ready supply of high pressure engine oil
regardless whether the car's accelerating, braking or cornering.
Now we're here with Bill from Dailey Engineering to talk about another aspect
of the dry sump system.
And this is the potential for a dry sump system to also improve engine performance
or engine power.
So Bill I think there's a lot of confusion about this topic and maybe a lot of
misinformation.
But let's just start with one of the products that you showed us off camera
before this interview which was your simple bolt on dry sump system for
a crate LS engine.
Can you tell us, with that sort of system, on a crate engine, would you expect to
pick up any power, and if so, how much?
- Well we've done some experiments where we do back to back crate motor remove,
install and test and somewhere between 15 to 16 horsepower gain.
It depends on the end user and what they do and how they install it in the car
and the system.
Some of it comes down to if we can make crank case vacuum or some
run 'em open, don't make vacuum at all and they just install 'em that way.
So you can make vacuum, that's one good thing about our dry sump systems.
But it depends on the power level and which system you actually run.
- Alright so there's a few things you've talked about there that I wanna jump
back in and unpack in a little bit more detail.
But first of all, can you just tell us with that system, whether you're pulling
a vacuum or not, where do you see the improvement in power, so 15, 16 horsepower,
where's that coming from?
- Well the biggest gain is getting the oil out of the motor, off the crankshaft
so there's no windage of the crankshaft rotating in a heavy, misty oil volume.
Making vacuum in the motor, does a couple of things.
The density of the air goes down so the windage is less.
But the biggest benefits you get is keeping the pressure differential across the rings
down so that on the intake stroke we keep the minimum amount of oil getting
across the rings into the combustion chamber, and that burns oxygen.
And if you burn oxygen, there's less oxygen to burn the gasoline.
So that reduces horsepower.
- Alright so that you're talking about there is during that intake stroke where
essentially we've got a low pressure area inside the combustion chamber
of above the piston and by reducing the pressure in the crank case,
you're helping to mitigate that oil making its way from the crank case up
past the rings and into the combustion chamber?
- Correct, correct it's the pressure differential across the rings.
- OK so when we're talking about this, is it fair to assume that getting that
pressure differential or reducing the pressure or making more vacuum in the
sump is gonna be beneficial or is there a point where that starts becoming irrelevant.
- It becomes irrelevant depending on the ring seal and the tension on the rings.
So a crate motor's got pretty moderately high ring seal and they seal very very well,
very low blow by.
So making vacuum on a crate motor's really not that beneficial.
So most of our power gain there is coming from the windage inside the crank case.
Now if we build a motor and we put lighter tension rings or ultra light
tension rings in, then we gotta make the rings work better, or help them work better
to keep the oil from migrating across the ring seal into the top end.
But a big power gain there is the frictional content of the rings, reduces the horsepower
drag in the motor, and that's a big gain in the horsepower.
So again just to unpack that a little bit, what you're talking about there is the
radial tension that the rings apply outwards onto the cylinder wall and of course
particularly during that intake stroke, we're really relying on that radial tension
of the rings to prevent the oil migrating up into the combustion chamber.
So by reducing or creating a vacuum at least in the crank case,
this allows you to then fit lower tension rings which then allows less frictional
losses without the oil making its way into the combustion chamber,
is that sort of a good way of sort of breaking that down?
- It is, it is, the lighter the tension, the more vacuum the rings need
to make 'em seal.
And the higher the tension the less they do.
- Now in terms of that vacuum though, is there a point where too much vacuum
actually can be a negative affect on the engine, can we go too far?
- The one drawback is you can suck blow by gases from the piston,
by the rings, through the wrist pin bore interface.
And what that does, puts hot exhaust gases down the wrist pin bore,
blows the oil out of the interface and that's the term sucking the wrist pins dry.
So that can burn up wrist pins.
It depends on the ring tension, how much blow by, the motor,
the build, the power level.
So drag racers usually want as much vacuum as I can give 'em.
I mean there's no such things as too much.
Road racing we usually aim for 12 to 14 inches.
And then the motor builders define what they want in between.
So each builder's different, we tune the systems accordingly and there's no right
or wrong, there's just no magic, you deal with it, you define it
and then you do it.
- You've talked about the danger there for the wrist pin.
Is there also the potential to end up actually sucking air in through let's
say the front and rear crank seals?
- Well if you have too much vacuum you can crack 'em open.
A factory seal has, it's effectively a vacuum regulator.
It's a spring loaded lip seal.
And so based on the diameter, the smaller they are, like the front main seal on an LS
will clock up around 12 to 13 inches of vacuum.
Sorry the rear main seal will crack off because it's bigger.
Front main seal around 18 inches.
If we change those out and we put in a real good, like an allied seal,
teflon lip seal, they're pretty much good for any vacuum so they won't leak off.
If I have a crate motor and I run too much vacuum, and I suck air in through
the rear main seal because I have too much vacuum and I run a clutch,
well that clutch is gonna end up inside the seal and inside the motor.
- And that's pretty abrasive so you don't really want that inside your engine yes?
- Correct.
- OK so in terms of actually controlling or regulating the amount of vacuum that
you're producing inside the engine, how are Dailey doing that, what's the
design elements that go into your particular systems to suit a certain
application?
- Well the pump's always made to be the max possible.
To regulate it down you can do two things, you can run an orifice in the
valve cover, and that's a flat vacuum decrease across the board from
light load to max RPM.
The better scenario's a vacuum regulator.
So you can set it at 12 inches, 13, 14, as much as you want, but you can only
set it as high as the pump will give.
So if I have a pump that'll make 18 inches, and I set it at 12 then the pump can
degrade over time but it won't go lower than 12.
If it does, either the pump's going away really bad or the motor's blow by
has increased and the motor's going away.
So that's a real good way to regulate it down and control it to the vacuum
levels that the engine builder wants and is tunable.
- This is probably a good time just because of what you've just mentioned there
to talk about monitoring the vacuum or at least the pressure inside the
crank case.
So do you feel that's a good way of monitoring your engine health,
getting an idea of how well the rings are sealing or if there's potentially
some catastrophic engine failure that may be imminent?
- Absolutely the misconception is I run a Dailey pump, but they don't know which
one they have so they seal the motor, and they just figure well we're making vacuum.
But not every pump's accordingly correct for the motor and what I recommend,
just like you'd monitor oil pressure, if you have an oil pressure issue,
it shows up, pressure degrades over time, you get a motor issue.
If I'm gonna seal the motor and make crank case vacuum, I wanna know what it is.
And it's the health of the motor, as it goes away over time,
it's giving you an insight as to hey maybe there's something going wrong in the motor,
be it, pay attention, be aware of what's going on.
- Now just in terms of the number of stages that you include on a pump,
and we were talking about the stages you've got, the main pressure stage,
and this draws the oil from the reservoir and actually pumps it through the engine
but then you've got the scavenge stages as well which could be one single
scavenge stage drawing the oil out of the crank case and returning it to the
reservoir, or of course you can have multiple scavenge stages.
So can you talk to us a little bit about how you decide how many scavenge
stages are right for a particular application?
- Well we find like on a V8 you have four bays.
So we use divided oil pans and there's one section per bay.
So that's four scavenge sections, mandatory.
And then you have a pressure pump, you could have optional turbo
scavenge section, an added vacuum section, and they have lines that would
just go to the valve cover.
So there's no right or wrong.
And then we have our same LS pan but with a production based system.
It's designed to fit in a Corvette.
So now I have a motor mount and a rack that I gotta fit in, and it's a three
stage pump.
Same V8 motor, but it's gotta be compromised.
So I combined bays one and two together and bays three and four together to make
it a simple three stage pump.
So no right or wrong but it's where it has to fit into is what drives the design.
- I think it's probably really easy to lose sight of the fact that particularly if
you're looking at a five stage pump, they do tend to get quite long,
and as you've mentioned, making that fit and work in a production engine bay
without modifying every other element of the engine mounting can be quite complex.
Now the other topic you mentioned there is about the divided bays.
And again there's a little bit of misinformation out there I think in general about whether
it's best to have these bays sealed completely, so essentially each pair of cylinders in the V8
is sealed from the next pair.
Is this essential, is it beneficial or is it detrimental in your opinion?
- Well there's no right or wrong again, so I've done quite a few motors where
we've been designed to seal the bays and every time I've ever done it
I've lost power.
And when I picked up the power, I've opened it back up to let the bays
breathe between each other.
So I'm a big fan of let the bays breathe.
But if you look at a very specifically designed race engine like a Kart,
they're all sealed, divided and sealed.
But they get to spend billions of dollars designing, developing, those motors specifically
where we build aftermarket products that bolt on everybody's motor.
So I try to do generic things at a very high level on a production based level system,
and again I've found that letting 'em breathe together is better than
sealing 'em off.
- Alright look Bill that's been great to get some real good insight into your systems
there and how it's possible to actually make some additional power along
with adding reliability to your engine.
If people wanna find our more about your products, how can they reach out?
- Well the website is www.daileygineering.com it's the name Dailey Engineering all spelt
out, all one word.
We got a phone call you can call, I'm always there and we're willing
to listen and talk.
- Great thanks for your time Bill.
- Thank you guys.
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