Dry Sump

[fast70]

I have been wondering about a dry sump for some time now and have a couple of questions. First, does it require a special dry sump case or will a stock T1 version work? Can the oil from a full flow mod just run through a dry sump tank? What does a dry sump pump do that makes it special? What are some of the advantages of having a dry sump?


These questions are probably stupid,
fast70

:stupid:

[kdanie]

A dry sump oil pump will have multi stages, that is more than one pump. A normal pump will scavange your case to the tank but you have no way to get oil from the tank to the system under pressure. A dry sump pump will have a scavange pump (sometimes more than one) to pull oil from the engine and put it in the tank and a pressure pump to suck oil from the tank and pressurize the engine.

A normal case can be used.

Advantages? More HP due to less drag on the crank from oil sloshing around it. More consistant oil supply, the stock oil system can suck air in certain circumstances.

Is a dry sump system necessary? Yes, if you need one, like road racing where cornering can expose the stock oil pickup or drag racing where every possible HP is desired.

ken

[lightning bug]

Not a stupid question at all. CB's dry sump system only uses 1 pump. It has 2 sets of gears so an external pump isn't needed. Its also not all that expensive. The above is true and also you never have to worry about starving your bearings of oil. You also eliminate the need for a sump extension. With a dry sump you'll have a remote tank to hold your oil. CB's is something like 8 or 10 quarts and is baffled to eliminate foaming. I'm going to use this system on my T1 2276T street car.

[Chris Percival]

How does the crank get lubed on a dry sump system?

[Shad Laws]

Hello-

I'm going to elaborate a bit in an effort to clear up some confusion...

Let's ignore the oil cooler for a sec because there are many different variations on how to do it.

A typical wet sump system works like this:

Sump -> Pump -> Filter -> Pressure Relief -> Engine Oil Galleries -> Sump

The sump is basically a "catch" below all the engine components, using gravity to get the oil back in the sump.

A typical dry sump system works like this:

Oil Tank -> Pump Pressure Stage -> Filter -> Pressure Relief -> Engine Oil Galleries -> "Sump" -> Pump Scavenge Stage -> Oil Tank

The oil is drawn from an external oil tank (where aeration is removed and there are no moving parts to create windage) and put through the engine as normal. Then, one or more scavenge stages suck the sump of the engine dry, often taking up air, too. Additional stages could suck from rocker boxes or turbos.

Usually, the oil coolers for a dry sump system are placed on the scavenge side of the system - after the pump scavenge stage and before the oil tank. This means that they have no pressure running through them. It also means that the pressure stage of the pump takes oil as directly as possible straight from the oil tank to the engine.

Take care,

[Type 5 Joe]

I actually use these on my motors...

Any application would benefit from these...

I do mostly off-road.

Positive piston displacment, the main benefit. Less combustion pressure in the back-side of the pistons, frees up the power.

You'll need to run an inlet hose (from the tank to the pressure pump) that has three times the flow volume, or you'll get low oil pressure readings.

Making an effective oil breather system for the oil/air (tank) is the big problem. Nobody makes a good one, and I've got about 25 hours into mine.

Shad is basically correct on his post.

- Joe

[chigger]

I just finished a major search on this subject the other night.
CB has the least expensive and easiest to use pump. You would have to blue print it just like a regular pump. The large quantities of oil the tank holds would definitely help with cooling the engine. Another reason to use it is so you can set your motor lower or the car lower without worrying about the ground clearance problem of a added on sump.
The only problem the mod seems to have is I think they recomend a smaller pulley to clear the pump. The information on the site was not exactly clear. Without the actual parts it is hard to know.

[CLKWRK]

Helo everybody,

I am running a dry sump in my ghia. It takes 15 liters of oil to fill the system, so oil changes are not cheap.
I tried using a CB pump, but I diddnt like it, so if anyone is looking for a used CB two stage dry sump pump, I have one for sale.

Bry

[Wally]

You guys mention that the windage effect of the crank and piston back side is drawing power. Doesn't the factory 914 ' windage tray' eliminates that effect largely?
Also, neutralizing the windage effect by the windage tray, I thought that the a multi stage dry sump pump costs more power to drive it than it freed, thus resulting in a less power situation with a dry sump system? The mean benefit then left being the secured lubrication with racing applications...
Poor quality dry sump pumps leak and lose pressure losses because of different materials expanding differently (iron/aluminium) and bearing issues of the pump gears. Therefore good dry sump pumps are very expensive ($ 500,-- - $ 700,-- or more).
Also, most all reputable tuners in Germany use a stock 24 mm pump in their own (!) engines and make regular drag starts with it, even in 226 DIN hp (tested) 2733 cc cars that do 0-62 in 4,5 sec.
My guess therefore was that although the system in itsself is very good, we obviously don't need it in a street car application.
But if anybody did any testing and found they gained hp, I would definitely reconsider...
Walter

[Chris Percival]

I thought parts of the crank were splash lubricated?

[lightning bug]

What didn't you like about the CB system? Thanks!

[Alex]

In the engine gallery you will find a picture of a dry sump pump that Eddy Remmele made. It is 30/26 I believe but from the setup identical to the Schadek (CB) pump. He told me that he will not make them anymore. It was not cheap. If there is enough interest maybe be would get him to do them again.


Alex

[kdanie]

Chigger, The large quantities of oil do not help cool the engine, it just prolongs the warm up time until all the oil is up to a useable temp. All the oil must be at 180 deg. F before you run the engine hard our you may have problems. You must run a good cooler and thermostat in the system. Most racers that use drysump systems have heaters installed to preheat the oil and reduce warm up time.

Chris, All the bearings are pressure lubricated, the pistons and cam/lifters get "splash" for lubrication but if there is too much oil getting wrapped around the crank it costs HP. I think squiters to the pistons, cam/lifters with quick drainback is the best way to go.

Wally, I have heard that the 914 windage tray can actually make the problem worse by not allowing enough oil drainback on high volume systems. I don't have any experience with it though.

ken

[Chris Percival]

Thanks Ken, so you need to rig up some lubrication of the cam/lifters and what about the big end bearings, they pressure lubriated too? Sorry for hijacking the thread guys, just a good chance for me to learn something.. Might be somthing to think about in the future for the track, though for now its just a deep sump for me...

[Shad Laws]

Hello-

You guys mention that the windage effect of the crank and piston back side is drawing power. Doesn't the factory 914 ' windage tray' eliminates that effect largely?

It helps, but not as much as a dry sump.

Nowadays, just about _every_ production engine has *some* sort of windage tray, whether integrated into the block (for an aircooled example, look at a Corvair) or in the oil pan.

A good dry sump system helps quite a bit more, though.


Also, neutralizing the windage effect by the windage tray, I thought that the a multi stage dry sump pump costs more power to drive it than it freed, thus resulting in a less power situation with a dry sump system?

No. The higher you go up in racing, the more stages they use...

They also use vacuum pumps to drop the air pressure in the crankcase, further reducing windage.


Poor quality dry sump pumps leak and lose pressure losses because of different materials expanding differently (iron/aluminium)

Iron gears in an iron-bodied pump will give the highest pressure. Simply seal the iron body to the aluminum case on the outside and you're golden. Yes, I know this is contrary to "common knowledge," but think about it...


and bearing issues of the pump gears. Therefore good dry sump pumps are very expensive ($ 500,-- - $ 700,-- or more).

The closer and closer you want to get to *perfect*, the more it costs.

For a situation where competition isn't that heavy, i.e. a street car or amateur race car, a simple 2-stage pump is *often* the best bang-for-buck.


Also, most all reputable tuners in Germany use a stock 24 mm pump in their own (!) engines and make regular drag starts with it, even in 226 DIN hp (tested) 2733 cc cars that do 0-62 in 4,5 sec.

The stock pump isn't that bad...

My guess therefore was that although the system in itsself is very good, we obviously don't need it in a street car application.

Of course you don't *need* it. But it's a nice thing to add :-).

But if anybody did any testing and found they gained hp, I would definitely reconsider...

All well-built dry sump systems save power.

I thought parts of the crank were splash lubricated?

A dry sump system lubes the main, rod, and cam bearings, and the lifter bores (and therefore pushrods, rocker arms, and upper valvetrain) the _same_ way as the wet sump system. It's pressurized from the oil galleys, after the last pump stage (which, for a wet sump system, is also the only stage :-).

The lifter faces, cam lobes, wrist pins, and cylinder walls are splash-lubed from the oil spray coming off the main rotating assembly. Of course, other modifications can change this a little one way or the other.

In the engine gallery you will find a picture of a dry sump pump that Eddy Remmele made. It is 30/26 I believe but from the setup identical to the Schadek (CB) pump. He told me that he will not make them anymore. It was not cheap. If there is enough interest maybe be would get him to do them again.

There's a 914 racer somewhere on the East coast that custom-makes them, too. But, like Remmele, I think he's kinda lost interest in making more due to tiny quantity. If curious, ask Chris Foley for more details - I'm just repeating what he told me.

Chigger, The large quantities of oil do not help cool the engine, it just prolongs the warm up time until all the oil is up to a useable temp.

_Absolutely_ correct.

If you use a dry sump, you _really_ need to use a real, temperature-based thermostat, not the pressure-based stock one.

Take care,

[CLKWRK]

Hi,

The scavenger side of the pump was not big enough, I was getting too much oil accumulating in the case and blowing out my crank pulley. I used an old cummings machine co. pump instead. It is still a 2 stage, but I have a Larger scavenger side, almost twice the size of the primary side.
I guess if you are running a non turbo application, then the CB pump should be ok. The thing is, since my turbo is down low, I am using my scavenger pump to evacuate the frothy-hot oil out of the bottom of the turbo, and pump it to the front of the car to the oil coolers and back to the oil tank.

BRY

[petevw]

where can i find a "temperature-based thermostat"?
any info?

i am running a drysump. it takes forever to warm up. running 3/4" pipe/hose, 96 plate cooler at the front of the car, cb tank behind rear seat, and a "cummings" oil pump used on formula vee race cars.


later,
pete

[CLKWRK]

Pete,

theres a thermostat in my front cooler (rx-7) and a thermo switch wit ha fan on my 96 plate rear cooler. You can buy an oil thermostat from bugpack (part#3061).

cheers, Bry

[Alex]

I have one lying around somewhere here.....which I will most likely not use.

Alex

[chigger]

You are absolutely right on having to get the oil up to temperature. In fact I was thinking about a heater on the tank to help it heat up to operating temperature and insulation to maintain it. However I have a tendency to think on the extremes. I was considering running a race hard for say an hour straight. A large quantity of heat spread out over more oil would lower the overall heat of the oil allowing it to be cooled easier. Granted a large cooler with a fan would probably work just as well.
Another advantage of a dry sump system is if you loose oil pressure in the engine and you have a low pressure engine kill switch the sump would have enough oil in it to allow the engine to coast to a stop without loss of oil damage. Assuming of course it is not the oil system cuasing the problem. An oil level switch can be used in similar fashion.
I have been trying to figure out how to get a 1600 engine running 500hp to last a one hour road race. The heat generated at this level of tune is tremendous. Sometimes when you mentally really push the envelope it helps you solve problems at a lower more realistic level.

[4agedub]

Hi
On my type 1 I'm running a 3 stage dry sump pump. I think the make is bugpack or cb.

There is one feed line from the tank to the pump 3/4". Then from the pump there is a 3/4" pipe to the full flow port.

Scavage side theres the std oil scavage in the block, and a pipe from the sump plate to the pump. The return line is 1/2" going through a oil filter and cooler back to the tank.

The tank can hold + - 10lt of oil and has got baffeles. I use the same tank in my type 4 with a normal empi dry sump pump.

Now the problem is that I seem to get a lot of aerartion in the tank.... any ideas what it can be? With the engine just free revving the aeration can be seen on the tank side dipstick.

Please any ideas will help....

[CLKWRK]

hello,

is that 3/4" id or od, I am using 5/8" id from the tank to the pump and I think it may be restrictive as the 911 system uses what looks to be a 3/4" id pipe to and from the oil tank.

For you aeration problem, you could icrease the size of your retun line, maybe it is too restrictive and is causing a spray effect when it enters your tank. Low pressure high volume on the scavenge output and suction side, that means big pipes, not as important for flow on the pressure side feeding the bearings

Is there such thing as too much scavenging in a dry sump? I always thought that more is better, a vacum in the case is desireable for hp and less oil leaks :)

Bry

[judgie]

i run a dry sump in my hill climb/sprint car.why? i have over £5k in parts in the engine and want oil presure at ALL times, you can not get that with a wet sump.

[4agedub]

If the oil pressure stays up, is the aeration such a big problem?

I drove the car and the oil pressure stays at 5bar, no oil pressure drops. Would'nt the air be pressured to allmost nothing when the oil is pressurised?

[CLKWRK]

bubbles in the oil are very bad because air does not lubricate, the whole point of the dry sump is to eliminate air in the system. Air also will compress, so your pump will have to work harder to pump the same volume of oil. I dont think there is a huge problem if the oil pressure stays up, just make sure the oil going into the pump isnt frothy which I highly doubt if your tank is big enough.

[4agedub]

I understand what you mean by the bubbles does not lubricate... but if the bubbles are compressed and the oil pressure stays stable does'nt this mean that there is proper oil in the system?

Sorry to ask all the stupid questions, but I'm at a dead end here.

I've tried using a thinner oil, checked for vacuum leaks....

This weekend I will try to install a 3/4" hose for the return as well and discard the 2nd oil cooler and 2nd fiter for experimental purposes to try eliminate the aeration.

If the aeration dissapears I think I will install a 2nd oil cooler on the pressure line from the pump to the engine...