Dry Sumps, Wet Sumps AND Accusumps Explained | MounTune [TECH TALK]


– 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
make sure you give it a thumbs up and if you’re not already a subscriber,
make sure you’re subscribed. We release a new video every week. And if you like free stuff, 
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48 thoughts on “Dry Sumps, Wet Sumps AND Accusumps Explained | MounTune [TECH TALK]

  1. NOTE: Around the 7-minute mark David means to say that the DRY sump setup is cheaper when compared to the amount of work and development that goes into getting the wet-sump setup discussed to be reliable. Everything else is spot on, just a mix up of words 😎- Taz 👨🏻

  2. Accusump has saved me from the disasters of my inadequate sump designs so many times, for over two decades.
    They are worth every single cent on a wet sump engine and very cheap insurance.
    AND, yet another great and useful video from HPA. Thanks again.

  3. I've seen a lot of the Australian tuners using the accusump's, motive video is where I first saw this system and it seems to really work on the RB engines with their notorious oiling problems. Looks like a cheap and easy way of keeping the engine safer on a wet sump

  4. Favorite video to date… mostly because I have been on the fence for an accusump for while, and this sold me. Not flashy, but exactly what I needed to hear.

  5. Thanks for sharing,awesome parts, I definitely need those but i've seen one available on Lindsey Racing for 944/968 turbo with belt mounting unfortunately..and it needs to remove the A/C….and…..it's so expensive!!!
    it's more than 6000 dollars including the tank and the hoses….just like the amount of a stripped engine.

  6. Some of you may have no idea just what a race engine's oiling system goes through – at the end of this comment there are a couple of Porsche dyno' test rigs specially designed to try and replicate the dynamic loadings, the actual total G can't be done in a rig, just the effective angles – something of an eye opener!
    A simple 1G corner will be the equivalent of a 45 degree inclination, a F1 car that has a peak lateral acc'n of 5G is like the power unit at a 75.8 degree angle, if my math' is correct (SOH?), even a 'mere' 2G is ~60 degrees! From that, some of you with 'V' engine may realise it isn't just the oil in the sump that's the problem, but oil not being unable to drain from the outer bank, and in extreme cases, the oil can be forced from the sump back up into the outer head – so with those engines, it's a good idea to consider a scavenge segment for each head, or at least the outer head if there's a long sweeper.
    I believe the the final sweeper at Hampton Downs, for the Kiwis, has claimed quite a number of engines, including some traverse inline ones.

    Some of you watching this may not have access to a data logger, or perhaps a warning isn't so noticeable in the heat of competition – an old-school trick was to use an additional high-pressure oil switch, preferably as far from the pump as practical, connected to a large light on the dash – an indicator light was commonly used – made it rather obvious if there was a problem! NOTE, most OEM pressure switches are barely 10-15 PSI, use a proper one of at least 35PSI, like these – https://www.demon-tweeks.com/nz/mocal-low-oil-pressure-switch-372393/

    https://www.youtube.com/watch?v=fv53RbvgfGc – flat six at the 'ring.
    and
    https://www.youtube.com/watch?v=Ny9xl7iWayU – V8 ditto

  7. There's a rule proposal for NASA's spec e46 to allow accusunps. Hopefully it passes.

    Awhile back the SCCA was opposed to Geartronics style shifters in the P2 class but it's been a godsend for prolonging the life of motorcycle engines in cars.

    "Spend money to save money" is a common pattern in motorsports. And wherever it rears its head it will be opposed by those with good intentions.

  8. Has anybody attempted using a centrifugal pump to transfer oil to the reservoir? It would keep parasitic losses down all the while reducing cost and weight.

  9. Love how the hp guy went back to make sure everything was understood. I would have missed the moving pickup part if he didn’t go back and would have never heard of one before. Thanks.
    Keep up with the great videos

  10. I'm pretty sure the accusump has the added benefit of keeping your bearings loaded prior to startup//cranking – they also have a (smaller) unit for turbo(s) as well

  11. Great video. I had no idea about accusumps. They might be a more reasonable idea for my drift E36 along with some baffles. A dry sump would cost more than the car 😂

  12. A very good explanation of the options available to prevent oil starvation. The most concise and thorough video I've seen on the topic. Great job!

  13. I’d like to hear about Piston oil squirters that are mounted on the main bearings to assist cylinder wall lubrication once the dry sump system eliminates windage. I’d like to hear how they further assists the tuning window by cooling the Pistons. On another note; Robert Yates, I believe it was, did a test. He placed wireless pressure sensors on the main bearing oil feed passage in the block and also within the cranks oil passage that feeds the rods to see what is really happening. The centrifugal force on larger bearings actually started to create so much pressure it would overcome the oil pump pressure and starve the bearing. It sounds counter intuitive but that’s what happens as RPM increased. NASCAR guys are pretty smart.

  14. Another really great load of information, knowledge and experience their. Many of us only have an oil pressure gauge to monitor, so this is really valuable.

  15. @High Performance Academy, a trick that BMW has been doing on their "M" engines is something relatively easy to duplicate on any engine at home for cheap. Use a scavenging pump to pull oil from the front of the oil pan and dump it in the rear sump area. Just gotta pull the pan off and tap it for some AN lines. Then wire up the electronic oil scavenging pump which can be had for relatively cheap. You can google how the S55/S58 in the M2/M3/M4 etc. work by googling "S55 engine pdf."

  16. Guys that are running turbochargers usually end up going to a wet sump. One of my friends decided to go back to a wet sump because he said the dry-sump was just weighed the car down too much.

  17. Wet sump is the way to go. Reliable oiling, made to withstand lateral G force. Simple system, excellent engineering. Using common sense.

  18. Very good video! Lots of important info. I'll need a baffle system for wet sump and an accusump system just adds to the safety of keeping the engine alive.

  19. Forgot, another use for an Accusump is in pre-oiling an engine before start-up.
    If a shutoff valve is fitted to the Accusump, before shutting down the engine, run it at a fast idle (where the oil pressure reaches it's operating level) and close the valve – this should maximise the oil volume in the reservoir. Then, before starting the engine, open the valve and the Accusump will prime the oil ways, lubricate all the bearings, etc – this is especially beneficial if the engine sits a bit between running periods and/or is running a lot of valve spring pressure on bucket/flat cam' followers. Hmm, thinking on it, some vehicles have a clutch safety switch that prevents cranking without depressing the clutch – bypassing that to avoid thrust bearing wear, especially with stronger clutch diaphrams, on startup when the bearing is reliant on a residual oil film, is best – but an Accusump will give lubrication there, anyway.

  20. Wow this was awesome how the exspencive dry sumps work and a few options with budget and weekend track cars in mind

  21. Forgot, again, some (older) belt driven engines have the oil pump/dissy driven independently by a jackshaft pulley – this can be spun for oil priming, pressure and leak check before fitting the belt and finishing assembly. Vauxhall slant 4 and, IIRC, Ford Pinto SOHC 4 come to mind but they may be too old for most to know?

  22. As someone forced to run a wet sump on a budget race car i know all about this. The sump I use is quite modified and I utilise a big oil cooler as a deaeration device. Works but far from ideal.
    Having in the past used drysumping on a wings and slicks Chev powered tintops it is so nice. you do not race with one eye on the oilguage.
    Some engines with external oilpumps you can simply use a 2 stage scavenge pump. And utilise the factory pump for pressure.
    Or baffle the well of the pan completely and use an external pickup. I have used those on Holden sixes for 30+ years. Again far from ideal but works.
    Dry sump toothbelts should be changed regularly and protected from rocks. Even then fine stones still get in but do not damage the belt, just not near as much, But between starts always have a look at the belt and pulleys. I have cleaned out fine stones imbedded in them a few times .I will never be an advocate of accusumps, they probably help but more trouble then their worth.
    And engine shutoffs for low oil pressure is simply dangerous, engine shuts down and the car is off the track.
    Limp home mode may help but at say 7000 rpm again effects the car balance on a corner. And the damage is done,, though turn it off as soon as possible and probably just replace the crank bearings, the only thing immediatly effected

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