- One of the biggest killers of any
performance engine is problems with the lubrication system. Maintaining a consistent supply of high
pressure oil to all of the bearings, as well as all of the other engine components
is critical if you want any kind of reliability. Of course when you take a factory road car
engine and you put it on a racetrack, with sticky slicks and you pull a lot of
lateral G force, this can be problematic. We're here with David Mountain from
Mountune to talk about the development of some of their oiling systems and in
particular, dry sump versus wet sump. So I think, David, it's fair to say that if
budget is no constraint, if you want the best of the best, you got to a dry sump
lubrication system. For those who aren't aware what that
term even means, can you talk us through how a dry sump lubrication system works? - OK so basically the name gives you a clue,
you're taking the oil out of the bottom of the engine, you're putting it in a separate
tank, somewhere in the car, and what that means is that it's normally a
tall tank where you can keep control of the oil. So you're always picking up oil, rather than
picking up air which is what happens in a wet sump. So it's a much safer result for racing
engines. - Yeah I think that's probably a good place
to just to back to. The problem really with your factory road
car sump is as you say, it's wet sump, so that means the oil is stored in the sump,
at the bottom of the engine and the problem is when we've got very high
lateral G force, cornering forces, plus braking and acceleration for that
matter, the oil can run away from the pickup and you suck air and that's where you get
problems? - Yeah and also because the oil's in the
bottom of the sump it's getting picked up with the crankshaft, you get a lot of windage
and aeration going on. If you ever look at an engine on a dyno that
has a perspex cover in the side of the sump you just won't believe what's
happening, it's scary. It's just a massive through and there's only
a little bit of solid oil right down the bottom which is what you've got to try and pick up. - Now that's a good place to point out that
dry sump lubrication obviously is there to ensure that you've got a constant supply
of high pressure oil to the bearings. But there are some other performance
advantages there from reducing, as you've just mentioned, the windage,
windage losses. So can we expect to see a power gain from
going to a dry sump system as well? - Yes certainly, it's more noticeable on higher
speed engines. So if you're running an engine at probably
over 7000 RPM and certainly when you get up to 9000, 10000 RPM. You can see, typically on a two litre
normally aspirated Ford engine, we could see eight horsepower increase. - And when every horsepower is valuable,
that's a massive difference. - Yes, yes a big difference yeah. - Now let's just go through the component
form of the dry sump system. So you've mentioned there's a remote
reservoir that's mounted somewhere in the car. Another advantage of that, it allows you
to put the reasonably significant mass of the oil exactly where you want it in the
car for balance perspective. But then you've got the dry sump pump
which forms two functions. It's pumping the oil out of the engine
as well as pumping the oil back into the engine from the dry sump reservoir. Could you talk to us about the scavenge
side of that dry sump pump, 'cause we hear the term four stage,
five stage, et cetera. Can you talk to us about what that means? - Yeah you're quite right, the pump or
pumps are split into two different jobs. There's the pressure side and then theres
the scavenge side. Now whatever oil you've got in your dry
sump, you've still got to pick it up. So the more scavenge pickups you can
have, ultimately if you had four, one in each corner of the pump you're
going to stand a pretty good chance of picking that oil up, drawing it out and
getting it into your main tank. If you haven't got effective scavenge,
what starts to happen is you start to lose level in your main tank and your
engine starts filling up with oil. Now it's a bit, I mean things like Formula 1
engines, they have very complex systems. But typically we use a two scavenge system
so one at the front, one at the back and that works very well for most jobs. It's also probably worth mentioning here
that when any engine is running, you're inevitably going to have some level
of blow by which is the combustion pressure escaping past the rings, making its way into
the crank case. So particularly in high performance engines,
we generally end up seeing some level of positive pressure in the crankcase but
with a dry sump system, particularly with multiple scavenge stages, can you overcome
that? You certainly can and typically on our dry
sumped engines we pull a vacuum. Albeit a fairly small depression, but we
do. And we start off, if you said something like,
you want three times the capacity from your scavenge to your pressure,
that's a good starting point. I mean we have run more four or five
times, can't say that we gain a lot from that. So you've got to balance gaining power
versus losing power and driving more pumps and more friction. But yeah a small depression and two
scavenge is a good starting point. - Now conventionally we normally see these
dry sump pumps fitted external to the engine which does add a layer of complexity and
one of the problems I always worry about is you've then got a rubber drive belt from
the, rubber's maybe not the best term but a drive belt nonetheless from the
crankshaft pulley to your dry sump pump which is another potential source of failure. So can you talk to us about the development
of your dry sump systems. You've actually gone away from an external
pump? - Yeah over the years we've had huge
problems with drivers going off into the kitty litter, picking up stones,
wrecking the belt and obviously ending up with a damaged engine. So one our latest Ford Duratec style,
EcoBoost style dry sump, all the pumps wer internal, so they're
chain driven, internally, there are no external pumps or drives. Much more reliable, much simpler,
there's just oil in and oil out. And it's been a really good way to go. - Less room for error. Now that's all well and good. Dry sump, obviously that's the ultimate
if your class allows it, if your budget allows for it. But of course there are a lot of us at
enthusiast level that are running lightly modified factory engines where oil surge
on the race track is still a very big concern. You've also been involved in some classes
such as British Touring Car Championship where for some interesting rule reason,
they've actually stipulated you must stay with a wet sump system. What challenges does that give you and what
are the ways you can overcome that, how can you get the best results if you're
stuck with a wet sump? - Yeah it's a bit of a bone of contention
really because we and other engine builders have said for a long time,
it's actually cheaper to go *DRY* sump. But anyway it's an old regulation, it's still
there, and it's a major challenge. I mean the amount of work we put into
our wet sumps to get them to be reliable is immense. We have all sorts of things like moving pick
up pipes, we have trap doors around the oil pickup, one way valves. A big job and occasionally on certain projects
we have to add an Accusump which is like having a big syringe of oil connected to your
main oil gallery and the minute the pressure drops, it whacks oil straight into the main
oil gallery. Very simple but very effective device. - Alright there's a few things I want to
sort of go back in and unpack there because a lot of our viewers may not understand
the terminology you've just used. So let's start with the oil pickups. So in a wet sump you've got an oil pickup
that's physically bolted to the underside of the oil pump and its job, unsurprisingly
is to pick up the oil from the bottom of the sump. However the problem is when you're running
very high G forces out on the racetrack, the oil is physically sloshing around in the
sump, running away from the pickup. So you've talked about a moving pickup
and can you just tell us how does that work? - Yeah I mean basically the pickup pipe
tries to follow the oil. So if you've got a particular G force,
whether it be braking or accelerating, generally we see higher G forces under
braking, the oil's all trying to rush forward so we try and follow the oil as much as we
can with the pickup pipe rather than trying to contain it always because at high
oil temperatures, the oil is so thin, it just runs away. - So what you're basically trying to do there
is always locate the pickup in the location in the sump where the oil is trying to
run to? - Yeah exactly. - Now you've also got a little flag, kind of,
I'll call it a flag, I'm not sure if there's a technical term you use internally
for it, welded to the end of that pickup. So how does that help that pickup move
around? - Well it basically, obviously the oil is
rushing to one side of the sump and it's basically forcing, it's almost like having a
keel on a boat in effect, it's forcing the pickup pipe plus the weight of the
pickup pipe, the G force is moving it in the right direction, it just helps
that. - Alright so that's the pickup there but
that still requires you to actually try and hold the oil in the sump and again
when you're pulling in excess of maybe 1.4, 1.5 G in a corner, the oil is physically
trying to run away out of the sump. So is this where your trap doors come in,
can you tell us how those work? - Yeah we're running very high speed
logging and very accurate pressure sensors so we can see exactly what's happening to
the oil and we're very very careful. We're looking at drop outs on the data
logging and we've got features in the ECU where we'll only allow a drop out of a certain
limit for so long before we'll go into an engine limp home or even cut the engine. So we're looking at that and we're
constantly developing to try to remove those dips. Particular circuits have particular problems,
some circuits we don't have any problems. So basically then we run trap doors if
you like and one way valves around the oil pickup, windage trays that try and
keep the oil down below the crankshaft where it's trying to pick up the oil. It's pretty complex and there's a lot of work
that goes into it. And quite often, to be honest, one of the
cheapest ways of solving this, particularly if you're on a very limited
budget is go and buy, I think for a couple of hundred dollars, an Accusump system
whereby you haven't got to necessarily, you know we're forced a bit down the
direction because the race teams don't want to add anything 'cause this
Accusump weighs something and it's the package space. But really, if you're running your own
car and you just want a cheap and easy way of getting rid of oil surge, it's
brilliant. - OK it's good that you've brought that
up, the Accusump because this is a product that we do see in the enthusiast market,
it's quite popular. And it's not a product that we've personally
had much experience with. So I wanted to get into that in a little bit. Now you've already kind of mentioned it's
basically like a giant syringe but I'd like to dive in a little bit further on that so
how is the Accusump plumbed into the oil system? - It's very simply literally plumbed into the
main oil gallery and it's got like an air spring on one side so you charge
the system with air pressure. The idea is when you fire up the engine
and you pull up the revs, basically the oil overcomes the spring pressure and it
fills up the cylinder full of oil. So what happens is it's sitting there,
as I say, like a big syringe, the minute the oil pressure drops on the other side,
the air spring forces the oil into the main oil gallery and you get, obviously
only for a time period until it can recharge itself but it's normally enough
of a time period, you get different sizes and capacities, we tend to use the
fairly small, lightweight ones but it's on capacity of oil. The bigger the capacity, the more timeframe
you've got. But it normally gets you through the
specific problem you've got, cornering, braking under that specific
corner, you're out of the corner and as you're going down the main straight it's
recharging it. - So important to mention here that this
really is a safety backstop and particularly if you've got a completely stock engine that
does suffer from really bad oil surge, this on its own may not be enough to
save the engine but when you start using it in conjunction with some of the
other techniques that you've mentioned, it's enough to really give good reliability? - It is, I mean if you take a pretty stock
production engine, you'd pretty much get away with putting a very simple baffle in the
sump, just a static simple baffle that most speed shops sell or you could easily
fabricate it yourself, with an Accusump you're going to be in pretty good shape. - Right I think that's some really great
information for our followers out there because a lot of enthusiasts do want to
take their cars to the track. They don't want to be hurting the engine
but perhaps they don't have the several thousand dollars that a dry sump system
entails so hopefully everyone's got something out of that that they can
apply. Thanks for your time there David. - No problem, thank you very much. - If you liked that video
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