dry sump pump

[poe21]

So I have been searching for some time about dry sump systems. There is a lot of good information out there, but one problem I keep running into is that most of the comments are at least 3 years old if not 6. Many of the pictures don't show up in the threads any longer and, and the product lines have changed. Most of the links are also no longer valid.
So I will pose a few questions. First off, how are you running your pump? Off the water pump shaft with an external water pump? Any pictures would be helpful.

Another question would be, how many scavenge pickups are you running out of your oil pan. Is a 3 stage pump only good for 2 pickups for scavenging and 1 for crankcase pressurization?

Any change in products out there? I've seen pace and dailey engineering. Pace seems to have some problems with availability, maybe?

Are you machining your oil pans or welding them?

We will be running a cbr f4i again this year, and have been using a carbon fiber oil pan with no baffeling up to this point. We had never had a car running long enough to see the effects of oil starvation (which I believe we are occasionally seeing).

thanks
poe

[roostmeyer]

Adding an oil pressure "dummy light" is cheap and easy to wire up, as is adding baffling to an existing oil pan. A canton accusump oil accumulator is a cheaper alternative if you're just occaisionally uncovering the pickup in transient conditions. After listening to the horror stories from a UMR student that I had an internship with I'm not sure if I agree that a dry sump is a more reliable solution...

I think its easy to justify the weight and cost of a dry sump system, but if your team is having problems with keeping a basic car running I wouldn't be biting at the bit to add more complexity with a dry sump.

[poe21]

While I will keep that in mind roost, I do think that we will be going to a dry sump soon and would like to make it this year if not the next.
A "dummy light" can only be so accurate, and doesn't pick up all the short times that the pickup is uncovered. Over the course of 20 laps that can cause real damage in the engine.
I believe that baffling can be helpful, but overall will not solve the problem. In a skidpad turn where the pickup can be uncovered for a longer period of time, especially during pre-competition testing, the engine can very easily be starved and heat up. Also, many dummy lights only come on at 20psi, where as the engine should be seeing 50psi. If you have crossed the 20psi point, you could already be in a bad position.
Over all I do not look to justify the dry-sump theory with CG changes. We might drop the engine a half inch at most, which will be offset by raising the oil/canister/pump.

Some teams systems have failed, and I think that can happen with any part of the car that is not correctly designed, or has faulty parts from the factory. I plan on doing all my testing on the dyno before hand, along with in car testing, and if I do not feel comfortable with the security of the system, then we will run the baffled pan. I have a couple of engines to play with just in case I don't get it right the first time. I hope to at least design something that can be tweaked to run on the 2011 car.

Also, our cars haven't run long because we keep breaking spindles. Since I am in the department of powertrain, I will focus on my problems at hand.

[Poe]

We ran a simple baffle system and custom oil pan on our wet-sump F4i. It did very well, with oil pressure drops barely noticeable on the data acquisition, where before, it would turn on the low oil pressure warning light.

-Poe the first

[Adambomb]

We ran a crazy trap-door baffled oil pan for a three years that was painstakingly machined from a giant piece of billet. Looked good for "static" testing (i.e. engine running tilted 60 degrees), but on the track it would lose pressure. Our "quick fix" was to just add more oil until is stopped starving...which ended up being almost a quart. I'm pretty sure the crank was submerged, it smokes like crazy when you turn right, and it definitely eats power. Not a solution I can personally recommend.

I too have heard many horror stories about student-designed dry sumps, and even though we have talked about it over the years no one has made any real progress with it. Not to say it couldn't be done, just keep in mind what you have for human resources...

I think an accu-sump would make a nice step up though, cheap and effective as long as you're not relying on it for long periods of time.

That being said, anyone care to speak about dry sump experiences, good or bad?

[Wesley]

As a team that has tried Accusump to fix oiling woes... it's not worth it. The added complexity, coupled with the extra plumbing and weight, just isn't a good solution.

We did an oiling study in 2008 that the judges liked - the first thing they asked for was an oil pressure vs. lateral g plot, and I told them we don't have one because it's not the most important data you can have.

By looking at stock pump oil pressure output, and looking at what kind of pressure and flow rate you need to maintain bearing protection given your surface roughness, we generated a threshold of "reduced pressure" events and "critical pressure" events - basically we looked at dips in the data and categorized them into acceptable pressure dips - they allowed for proper lubrication, despite the drop, and into unacceptable drops, where calculations showed that bearing film thickness is not sufficient to prevent contact (I think the number is something like 10 times surface roughness or something like that, don't remember)

So once we had a metric, we went about testing baffles until we could eliminate the "critical pressure" events, and minimize "reduced pressure" events. We blew up a few motors in the process, too.

The biggest impact we found was oil pan geometry itself. The stock pan was far more sufficient than our new pan at controlling oil (deep sump, very compact sump footprint) whereas our new pan was just an extrusion of the crankcase. We ended up with a baffle that mimicked the stock pan design, with a plate on top. We reduced pressure issues to our goals, and then after verification with our pressure transducer, put the dummy light back on just for safety's sake.

In our testing of different baffle designs, we found it was very often NOT constant high-g turns that caused the most oiling issues, but high speed transients - slaloms, high braking force turn-ins, and the like. If you look at a tilted engine, you're looking at steady state. Even in skidpad, the engine oil only somewhat settles into steady state. It's all about transient slosh control, and once we designed a baffle that took care of that, we didn't have any more problems. Oil pressure doesn't fall off in proportion with lateral g, it has some threshold of "jerk" that causes enough slosh to uncover the pickup momentarily.

[Kevin Dunn]

From memory we've been running our dry-sump (student designed) for around 3 years now with no major problems. It's a 3-stage pump utilizing two stage for scavenging and one engine supply. We then use our stock internal pump to scavenge our turbo. We run it off of the water pump shaft and run an electric water pump.

As far as the pan: Last year we ran a welded aluminum pan with pick-ups. This year we ran into chassis packaging issues and we had to run a flat plate with fittings and pick-ups welded into the block. Engine mounts were 1" too low, same as our pan thickness.

In 2008, we showed oil pressure drops in transient conditions (especially skid-pad and slaloms). After testing a few different setups, we found that this was happening due to using the internal pump to supply the engine. The pump would have to scavenge oil from the tank, through a 12" line, then up into the stock pump. Using the 3rd stage as a pressure stage eliminated this, which is why we are now using the stock pump for turbo scavenge.

[michaelwaltrip]

Short answer:

Dry sumps are not worth the time/effort/weight/complexity when a simple trap-door style oil pan works great for this application. We were even able to lower the engine several inches, and sustained cornering at ~2g has minimal effect on oil pressure.

I had a design judge tell me that our oil pan closely resembled the wet sump pan that the Corvettes used to run(which I have not personally seen)

[poe21]

I realize that there are differing opinions. I appreciate all the information, and I need to do some digging and testing, but I really don't understand why people think that dry sump is failure. I thought I saw several of the top teams running dry sump (I'm pretty sure RIT and one graz school). I also heard from a guy that the new corvettes only run dry sump now. Maybe I was mistaken, but he did come to the car show with a brand new lingenfelter(sp?) corvette. Anyway, I would like to hear more positive and negative experiences from those who have tried dry sump. Also any pictures (I know that they are hiding around here somewhere) would be nice.

PS I am not trying to bash anyone's opinions, just wanted to get some more information about the dry sump system.

[poe21]

-Poe the first

HAHA... I hoped you might respond. It is an elite club

[Hector]

Originally posted by michaelwaltrip:
Short answer: Dry sumps are not worth the time/effort/weight/complexity when a simple trap-door style oil pan works great for this application.

In that case, nothing in racing is.

Good racing is a matter of millimeters and milliseconds. Maybe it isn't good for some teams, but I'm sure with enough improvements in other areas, going to a dry sump would be your best improvement. Plus, once you get the system designed the first time, it's fairly easy to recycle year after year.

Our pan's a half inch thick. Without frame tabs, the pan bolts are the lowest point on the car. That makes the single heaviest component (besides driver of course) several inches lower. I know our suspension guy appreciates it.


~2g has minimal effect on oil pressure.

~2g has no effect on our oil pressure. Lots of logs to back it up. The pressure vs. rpm histogram line is so well defined it's hard to make out the individual points. Looks like a nice, solid line.

In the end, if you think a dry sump is the best place to invest your efforts, or if you're just damn interested in doing one (this is a learning competition after all) then go for it. I'm all for them. However, when you say something like "We had never had a car running long enough to see the effects of oil starvation" it makes me think that just getting a car running and testing would be time better spent.

[Kevin Dunn]

I'm in total agreement with Hector. The dry sump we've had is proven and has required minimal development over the span of its use.

If I remember, I'll try and have someone snap some photos of our setup when I'm in the lab tomorrow or Saturday.

[Pennyman]

In that case, nothing in racing is.

To quote Pat Clarke, "This isn't racing...this is fun"

It's all about the justification.

[VFR750R]

Many a championship have been won without a dry sump. But the best solution to the problem performance wise, is a dry sump. I've seen pulley driven pumps, oil pump shaft driven pumps, and heard of pumps belt driven off the driveshaft (for vacuum assist only, no pressure sections).

I like the belt driven solution mostly because I don't like the idea of running an electric water pump (this isn't drag racing). But a really smart engineer could have both with some extra design work on the two pumps http://fsae.com/groupee_common/emoticons/icon_wink.gif.

The belt driven solution also allows fine tuning of speed, easier packaging of lines/pump, although some design work will have to go into adding a drive off the end off the crank or cam. Some of these engines have dry flywheels, in which case you can get rid of the flywheel cover all together, those with 'wet' flywheels will require new covers and an oil seal, and then the water pump port option becomes more attractive.

[abinley]

We have run a student designed dry sump for the last 2 years on our 600f4i. We use the factory pump to feed the motor and a single stage to scavenge. We have also used a dual stage when we were turbocharged. The pump is driven off the oil pump shaft, where the water pump normally lives. We use an electric water pump in it's place. The first version of our pump did seize at one point shearing off the tang on the driving shaft. The reason for the failure was the lack of an aligning feature in the pump, which was fixed in the new version with dowel pins. Our new pump has been flawless, and is about the size of a small mandarin orange ha ha! Here is a shoddy pic of the old 2 stage pump:
http://fsae.uvic.ca/gallery/th.../Oil%20Plate%202.JPG (http://fsae.uvic.ca/gallery/thumbs/Oil%20Plate%202.JPG)

[michaelwaltrip]

Originally posted by poe21:
I realize that there are differing opinions. I appreciate all the information, and I need to do some digging and testing, but I really don't understand why people think that dry sump is failure. I thought I saw several of the top teams running dry sump (I'm pretty sure RIT and one graz school). I also heard from a guy that the new corvettes only run dry sump now. Maybe I was mistaken, but he did come to the car show with a brand new lingenfelter(sp?) corvette. Anyway, I would like to hear more positive and negative experiences from those who have tried dry sump. Also any pictures (I know that they are hiding around here somewhere) would be nice.

PS I am not trying to bash anyone's opinions, just wanted to get some more information about the dry sump system.

This is true.

Several of the top teams do run dry sump. But those teams (usually) bring more people to competition than we have working on our car the whole year.

Back when we used to run a dry sump (05-07), we had many problems. Most of them stemmed from having only about 3 people who knew anything about it. We had a pully driven off the oil pump shaft (in place of the water pump) and our custom-designed pump was housed in the rear box structure. The pump was inefficient, the tank was always a problem (finding places to mount it, running extra oil lines, de-aerating the oil), the pully drive system required near-constant maintenance, and the whole system was about 10 pounds heavier than our current wet-sump system.

I have no pros to report from our system. Maybe other teams have had better experiences, but we just don't have the resources to invest in it. Nearly all of our car failures in those years were a direct result of the dry-sump. At least 4 engine failures (that i know of) plus two endurance failures due to an oil leak and oil starvation.

[RacingManiac]

Not being an engine person and all I can only comment on this based upon my observation of how our(Toronto) system works. When we are running the F4i we run a 2 stage(I believe) dry sump off the waterpump shaft, with custom pump sourced from UK, we also run the stock waterpump inline off the same shaft(imagine layout being [o][o][w]). The issues we've had have more to do with the shaft seal and face seal between the pumps may leak, mostly due to manufacturing tolerances. Most years that we've run the system its been pretty good AFAIK. Dry sump also allows for the chassis designer to place the motor a lot lower to gain some CG advantage. The system is no longer in use in 09 because of the engine switch to 450 single Honda.

If other Toronto guys read this maybe they can chime in...

[Joe the plumber]

Originally posted by VFR750R:
I like the belt driven solution mostly because I don't like the idea of running an electric water pump (this isn't drag racing). But a really smart engineer could have both with some extra design work on the two pumps http://fsae.com/groupee_common/emoticons/icon_wink.gif.

The belt driven solution also allows fine tuning of speed, easier packaging of lines/pump, although some design work will have to go into adding a drive off the end off the crank or cam. Some of these engines have dry flywheels, in which case you can get rid of the flywheel cover all together, those with 'wet' flywheels will require new covers and an oil seal, and then the water pump port option becomes more attractive.

Seems like a lot more work to not run an electric water pump. For the fact of easier packaging maybe but you now have to design new ways of running the pump. We have been really successful with an electric water pump. Oh and Hector you must of had one great oiling system designer if your oil pressure curve is a straight line.

[James Waltman]

I’ve been trying to decide for a few days if I should bother saying anything on this topic.

I guess that this means I will.
First up, we ran a dry sump on our ’04 car. There are topics on here with pictures of it.
We used this logic: Real race cars have dry sump systems, we’re using a motorcycle engine that wasn’t meant to corner like we do (oil starvation will probably be an issue), and we can lower the engine/car CG.

That was enough to get us started – and we didn’t hold back.

How much were we actually starving an engine with the stock oiling system? Dunno.
How much did we actually lower the CG? Dunno.
How much drag (in HP) does the new belt drive system add (a question during the Design event at comp)? Response: “Uhhhhh…..”

It was a very cool system though. And we really did lower the engine.
Then it failed on us at competition. The pump, plumbing, pan, seals, bearings, fittings, and most everything else worked well. It was an oversight on the modification to the crank cover that let the starter’s idler gear go wonky, fail, and ruin the block.
I’m sure we had hours of engine cranking on the dyno and in the car before competition. If we had been able to get two more minutes of cranking it would have lasted us through competition. No luck.
So, it was a system that we inadvertently modified that failed on us.


Originally posted by poe21:
…and have been using a carbon fiber oil pan with no baffeling up to this point. We had never had a car running long enough to see the effects of oil starvation (which I believe we are occasionally seeing).


So, you have an assumption that, on occasion, the engine isn’t getting enough oil but you have no baffles and no data. You’re proposing spending hundreds of hours to solve a problem that you might not actually have (or at least you can’t put numbers to the severity of it).
Same thing we figured.
Some basic baffles are less than 1% of the effort required to do a dry sump and would have a huge part of the benefit.

Wesley outlines the perfect method. Go back and read his post. He describes an engineering approach.

Identify a problem. Put some numbers to it. Set a target. Design, build, test. Achieve the target. Do it with the most efficient use of resources (time, people, weight, cost, etc).


Originally posted by poe21:
Since I am in the department of powertrain, I will focus on my problems at hand.


Finally, about the idea that you should be focusing on the engine while the rest of the car/team is having trouble: it’s wrong.
The point of this is to build a car – not a sweet engine. If they’re having trouble and you’ve got time to think about dry sumps – you should be helping them.
I really like Geoff Pearson’s way of looking at this: “If you are finishing under 800 points you don't have a car problem.”

This isn’t meant to be preachy and I’m not trying to talk you out of it. If the numbers say you need a dry sump you should figure out if you can afford it (in terms of time, people, resources, and money (probably in that order)).

[flavorPacket]

James, good post. BUT, I think you left out the pressing question, "What are you trying to get out of FSAE?" By all means, if the kid wants to learn how to design dry sumps, FSAE is the place to do it.

Second, the original poster is making the most common mistake in FSAE development: trying to do it all in one year. Do yourself a favor and spread the project out. Talk to your chief engineer and get a game plan. Get some newbies ready to take over. Give your system a full summer of testing. THEN, put it on your car.

[Calum Douglas]

All,
to dry or not to dry arguments aside I will attempt to offer some help:

1: Its really easy to make a rubbish dry sump system.
2: I spent 5 years working for ONE of the companies mentioned at the start, take it from me they don`t REALLY know what they`re doing!
3: The tank design is probably as important as anything else.

Make sure you dont spin the pump too fast, ensure the scavenge Q is several times pressure Q and make sure you dont design a rubbish PRV...

Reading this will help regarding the design of the gear pump.
http://ntrs.nasa.gov/archive/n...15230_1974015230.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740015230_1974015230.pdf)

Cheerio

Calum

[Mike Cook]

The main benefits of a dry sump are:

Lower engine and CG
No loss of oil pressure

The downsides are:

Cost
Complexity
Weight and space
Maintenance


At Maryland, we never ran an engine without an accusump or drysump. I can't really say that you have to have a drysump to maintain oil pressure and it seems evident that many other teams have found other solutions to this problem. With that said I can't think of a race series where it is legal to have a drysump and teams choose not to. Choosing a drysump means that you won't need to spend so much time designing and testing bafflings, and you won't risk blowing engines in this process. However, a dry sump setup is not really trivial especially depending on the system you choose.

History
In 04-06 we used the pace dry sump. We had to make our own mount for the pump. We were using an f4i and we replaced the water pump with the pace pump and drove it off the water pump shaft. I can't say that the pump was bad but making a mount for it was time consuming and annoying. Also since we got the pump in the UK it took forever to ship parts and started getting expensive.

From 07-current we use a dailey engineering pump. We worked with Dailey to design an integrated mount into his pump. The dailey pump still replaces the stock waterpump, but it is a complete bolt on part which is nice. Dailey's support is great as well. You can get away with a two stage, but we have always used a 3 stage which is probably overkill.


The Good
With a our current setup we have got our oil pan down to .5" which is about 2.75" less than stock. When the system is working, we never have any problems with oiling and we can run skid pads all day long without any problems. The system works and it is easy to carry over from year to year.

The Bad
Where to start? First off, a dry sump system is expensive and complicated. Good AN fittings are $15-50 a piece, hose is like $12/ft, the pump is around $1000, a good tank is $400. You can easily sink $2000-$3000 into the system. And I didn't really mention much about tanks, but I wouldn't recommend making your own.
With all of these aluminum fittings, new guys are bound to bugger up the treads which is going to cause leaks. Leaks knock you out of the endurance race. Replacing fittings gets expensive. Steel fittings are more durable but heavy. Thus, you need at least one guy who focuses just on the oil system and I wouldn't let anyone else touch it. If you do blow and engine you should probably throw away all the lines because metal gets stuck in them. The pump could get destroyed as well. Oil level is a huge concern, and we have had a lot of problems with either the oil level being too low or so high that it fills the catch can and pukes oil out the breather (which also knocks you out of endurance). We never had a great method to measure the level. Because of the complexity of the dry sump system I would guess we have blown about 3-4 engines in the last 5 years.

The weight of the system is bad. You will probably add about 10-15lb including everything. Packaging a tank is tough too because they are usually slender and tall.


If I did it all over again, I'm not sure I would go down the same route. Nowadays the newer engines have dry sumps built in and thats what I would look for. If your team is shooting for a lower CG for performance reasons, than going to a dry sump might be the right choice. Having a lower CG isn't going to hurt you of course, but depending on your diff setup, having a high CG might not be so bad.

I hope this helps.

Mike

[Mikey Antonakakis]

^^ that was a very, very good post

[Benn]

Originally posted by Mike Cook:
The weight of the system is bad. You will probably add about 10-15lb including everything. Packaging a tank is tough too because they are usually slender and tall.



I know you mentioned at the start of your post that dry sumps = lower CG, but after all the extra weight, and the tall skinny tank, how did the overall package fare vs wet sump in the CG regard? I'd guesstimate and say while the oil pan is 2.75" lower, you wouldn't have actually realised a net lowering of your CG of that amount... maybe half that?

This year we are running a dry sump too, and while packaging the tank ain't a huge issue thanks to our car having a fat ass, the amount of weight and complexity that the system adds really makes me think that a wet sump would be worth trying. Unfortunately at this stage our team is tiny, so we don't really have the resources to explore all the options, and the oil system is a legacy item, so on it stays.

Another point which is regulary brought up is that "real" racecars all use drysumps if possible, however I wonder if the ratio of oil system to total engine package weight in on a much larger engine is significantly different from our 600cc packages. When you are looking at a 8kg oil system on a 220kg car, vs maybe a 20kg system on a 1000kg car (imaginary numbers) the weight penalty is significantly different. With a much lower relative weight penalty it would probably be a no-brainer to go dry sump.

[Mike Cook]

Benn,

I still believe that there was significant lowering of the CG despite the added mass of the tank and other parts. Our CG pre-aero was in the 10.25" range.

In other racing series I think they push their engines a lot harder for a lot longer and a dry sump system is basically a requirement to keep the engine alive. Most formula cars are way over powered and aren't at wot for more than a second here or there.

[D Collins Jr]

Benn, your post makes me consider two things. 1, even at an entry level of "real" racing (with a V8 engine), competitive cars will have ~$20,000 sunk into an engine. You now have an investment to protect. That's something to consider besides the "weight penalty" is the durability bonus...if you plan to have your car running for awhile, and you're tying up cash in new engines, maybe the dry sump is worthwhile. 2, keep in mind that a four cylinder bike engine will weigh ~120-130 pounds (Or very roughly 25% of the car's mass). Lowering that even an inch will make a noticeable difference in your CG height. Add in an Oil tank, even on top of the engine, and it won't negate that lowering from a CG perspective.

[Benn]

Great replies thanks guys, we will definitely be looking at our oil system in more detail for our next car, from the amount of discussion here on the subject I think there is definite gains to be made in that area, especially since our engine packaging this year has kinda been an afterthought. We'll just have to see what kind of a solution we come up with once we have the time to throw at the problem http://fsae.com/groupee_common/emoticons/icon_smile.gif

[poe21]

While many of the responses weren't even close to the origional questions http://fsae.com/groupee_common/emoticons/icon_biggrin.gif, I have learned a lot just by the information given. I will not have the opportunity to run a dry sump this year after all. The team is going in a different direction structurally, and hopefully the dedicated "researchers" will be able to do more work in this area. Right now, I have welded up a much more shallow (than stock) oil pan that we will be using for testing. As of right now it has no baffling in it, but can easily be adjusted after some test data is pulled.

I also have a pretty amazing idea for a much cheaper dry/wet sump system that may turn into a grad school project. While it may only lower cg half as much as a true dry sump, it should weight less, and cost about 1/3 of the price.

[Kealan O Carroll]

Originally posted by VFR750R:

I like the belt driven solution mostly because I don't like the idea of running an electric water pump (this isn't drag racing). But a really smart engineer could have both with some extra design work on the two pumps http://fsae.com/groupee_common/emoticons/icon_wink.gif.



Haven't got as far as building ours yet (STILL Waiting for materials for the CNC :@ )but I've come up with a way of running the stock 4fi water pump and the oil pump off the same drive...confident it should workhttp://fsae.com/groupee_common/emoticons/icon_smile.gif

On a side note, if a scavenge stage is plumbed to 2 pickups, and only one is submerged, Im assuming that stage will draw in air through the uncovered pickeup yeah?

[Rex Chan]

kealan: yes, you should only have one pickup for each stage for the reason you mentioned.