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 Most of the links are also no longer valid.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