Dry sump oiling system

[mrmadmax]

Originally posted by GTM


...

Part of the idea is to stop the wind generated by the rotating crank. Place your hand over the suction side of a vacuum cleaner and the motor spins up faster because it's not dragging the air through the vanes, do the same to the exhaust, again the motor speeds up.

...

Cheers,
GTM

Interesting point, GTM. Thinking about this I would say, to this end, that there are two ways to decrease the power consumed by a vacuum cleaner (or in our case an engine due to wind): 1) block off the inlet or outlet to the impeller (or crankshaft) or 2) remove the air molecules from the impeller housing (or crankcase).

This second approach is very easy with a dry sump oiling system. I built a three stage custom dry sump system for a ZX6-R engine. Two scavenge stages, each with the capacity to move the same volume as the single pressure stage. The result was an empty sump and a crankcase vacuum well in excess of 18 inches of Hg. I always attributed power gains to improved ring sealing at high RPM due to the increased pressure differential, but I never considered the idea that the crankshaft no longer has to push around so much air, since the crankcase has less air in it!

I would agree that this is alot of work (having done it), and that a good scraper and a windage tray would go a long way, but what if the AIR is what's dragging down the crank?

Thoughts?

 

[GTM]

Originally posted by mrmadmax


Interesting point, GTM.
...
Two scavenge stages, each with the capacity to move the same volume as the single pressure stage. The result was an empty sump and a crankcase vacuum well in excess of 18 inches of Hg. I always attributed power gains to improved ring sealing at high RPM due to the increased pressure differential, but I never considered the idea that the crankshaft no longer has to push around so much air, since the crankcase has less air in it!

Thoughts?

Before switching vocations I'd woked a little with hi-vac evnironments. Something to consider is the lip seals need lube, also consider a double lip seal while under pressure before establishing a vacuum.

Can you explain for us why you went to a 2 scavange system including any calcs you used? Plus any special concerns for oil vapor recovery?

Cheers,
GTM

 

[mrmadmax]

Originally posted by GTM
Before switching vocations I'd woked a little with hi-vac evnironments. Something to consider is the lip seals need lube, also consider a double lip seal while under pressure before establishing a vacuum.

Can you explain for us why you went to a 2 scavange system including any calcs you used? Plus any special concerns for oil vapor recovery?

Cheers,
GTM

heh heh, the calcs were pretty simple... at steady state:

dm/dt = 0

In other words, we want the sump to remain empty, right? so the displacement of the scavenge pumps must be greater than (or at least equal to) the displacement of the pressure pump.

To ensure scavenging during a sustained turn, we opted for an oil pickup on each side of the pan. Each pump must have only one pickup, because the pump will tend to pump air before it will pump oil (similar to trying to drink a soda through a straw with a hole in it. All you get is air, because air is easier to move than a liquid). During the worst case scenario, which is a sustained turn or stationary on a crowned road, the scavenge pump is moving as much oil as the pressure pump (actually very slightly more because there is no restriction as in the pressure pump), so the amount of oil in the engine pan remains constant and negligible.

You are correct about the oil seals, and I imagine you could find a way around it, but if the seals are letting some small amount of air in, then the oil can't get out (which is why we have seals). No leak, no foul.

As far as the external oil tank is concerned, we really didn't have any problems with vapors. If we had, we probably would have placed a PCV valve in the tank, and fed that into the manifold.

 

[GTM]

Originally posted by mrmadmax
heh heh, the calcs were pretty simple... at steady state:

dm/dt = 0
...
(or at least equal to) the displacement of the pressure pump.

To ensure scavenging during a sustained turn, we opted for an oil pickup on each side of the pan.
...
You are correct about the oil seals, and I imagine you could find a way around it, but if the seals are letting some small amount of air in, then the oil can't get out (which is why we have seals). No leak, no foul.
...

I was hoping you knew the pump volume at max rpm. It should be an exponential number... in other words the oil flow cannot be on a linear curve at 1000rpm as 8,000rpm. The stock oil pump always has to be able to deliver in excess of the engine need or you would have pressure drop at high rpm. The excess just gets dumped back into the pan through the relief valve. You can re-route this through a secondary oil cooler which then gets sent to the resivoir through the scavanger.

I am aware of the cornering concerns but this can be circumvented by making a "V" shape in the pan and only 1 scavenger. I wouldn't give a lipseal 1 hour running in a dry enviroment. If it doesn't wear a groove in the crank it surely to burn itself to a crisp and thus loose the vacuum. Usually the oil resivoir has 2-3 times the capacity of the original system so should suffice. I gather you are not familiar with aircraft fuel and oil pickup systems. It's not just G forces for they fly upside down... it's a simple cost effective sytem.

Cheers,
GTM

 

[krustindumm]

Some aircraft systems use dual pickups (one in valve cover, one in pan) with a gravity operated check valve.

 

[Defiant]

I've heard of "windowed" V-8 research motors floating a baseball-sized wad of oil near the crankshaft, at speed. Still, I'm not convinced of the payoff being there for dry-sumping a street engine.

 

[GTM]

Originally posted by Defiant
I've heard of "windowed" V-8 research motors floating a baseball-sized wad of oil near the crankshaft, at speed. Still, I'm not convinced of the payoff being there for dry-sumping a street engine.

Sorry don't know what a "windowed" engine is.

I was running in one of my Lancia Appia engines in the stand using an electric motor for 7 hours as the factory recommended. However, I left the pan off and used the factory pump and what I thought was an adequate catch pan and shielding to contain the splash. I could not believe the amount of oil being slung EVERYWHERE including all over me. There was easily a half quart of oil in motion at any one time and this was on a 1100cc engine turning at 500-700 rpm.

As I mentioned before just check a full engine dipstick with the engine running and you will see it's 1-2 quarts low. It can't all be running down the head drain back holes which most often drop right into the crancase rather than along the sides of the block.

A lot of motorcycles use a dry sump system so it's not something reserved for some nut case or track racer. The harsh reality is this may be the wrong crown to discuss it with. It seems they only want to spend money of name brand flashy items that they can boast to the buddies about. I just don't see anyone really interested in R&D.

Cheers,
GTM

 

[Defiant]

Originally posted by GTM
Sorry don't know what a "windowed" engine is.

Well, the looney bastards cut holes in the webbing between the bearings and put Lexan windows in there.

I was running in one of my Lancia Appia engines in the stand using an electric motor for 7 hours as the factory recommended.

Heh, what a pleasant job.

However, I left the pan off and used the factory pump and what I thought was an adequate catch pan and shielding to contain the splash. I could not believe the amount of oil being slung EVERYWHERE including all over me. There was easily a half quart of oil in motion at any one time and this was on a 1100cc engine turning at 500-700 rpm.

Yeah, I've always wanted to start up a Datsun with no cam cover, just to see the mess. Drilled cam is one of the main oil galleries. Wheeeee!

As I mentioned before just check a full engine dipstick with the engine running and you will see it's 1-2 quarts low.

It's standing by in case of an emergency.

It can't all be running down the head drain back holes which most often drop right into the crancase rather than along the sides of the block.

Yeah, but all those motors in the world are getting along just fine that way.

A lot of motorcycles use a dry sump system so it's not something reserved for some nut case or track racer.

Yup, my simple little Yamaha SR-500 thumper is dry-sump.

The harsh reality is this may be the wrong crowd to discuss it with. It seems they only want to spend money of name brand flashy items that they can boast to the buddies about. I just don't see anyone really interested in R&D.

I am only skeptical about the real payoffs in it, I have no qualms with it being a better way to go.

 

[dsmturboawd]

Originally posted by GTM
The harsh reality is this may be the wrong crown to discuss it with. It seems they only want to spend money of name brand flashy items that they can boast to the buddies about. I just don't see anyone really interested in R&D.

when you find this crowd, let me know. tia.

 

[babell2]

After reading all this I think you guys have it pretty well covered. In Aviation where Radials all have dry sumps the rule of thumb is: Engine drive both pumps, Scavange pump is to be at least twice the volume of the pressure pump to keep up with supply. and Always carry more oil that required for all operations. After the Radial engine days a few Manufacturers continued to use a dry sump system but even with the increased benifits of cooler oil and improved free running of the engine internals most have abandoned the practice. Check with some form the nascar garages they still run dry sump systems to keep oil temps down. Are we going to enter a car at LeMans? For street it's neat but un necessary.

 

[GTM]

Originally posted by babell2
After reading all this I think you guys have it pretty well covered.
...
Are we going to enter a car at LeMans? For street it's neat but un necessary.

We are missing a lot of information such as factory pump capacity (gpm) at various RPMs and pressures.

I disagree with your conclusion if for no other reason you have given us no supporting argument.

Cheers,
GTM

 

[NDgsx]

I would think that the lip seals are in close enough proximity to journals to get adequate lubrication. I'll have to go look at a spare engine.
I can see a problem with sucking in air past them though. I'll have to ask my friend at the UW what they do with their dry sumped F4i engine as far as seals.

 

[MNGSX]

Actually if the oil feed pump is worth it's salt there will be no vaccum at the seal lip as the oil pressure is far above the vaccum.

I don't want to do conversions right now for In hg to psi...

Lets say we have a 10psi vaccum so -10 psi and 40psi line pressure. 30 psi at the bearings.

Please note that the vaccum also helps pull oil in the engine.

Skip the ricky ricy racer shops and sites.

Try Barnes, Peterson (fluid sys) and moroso.

There are usually atleast three scavenge pumps on v8s. That is a four stage system. The 4th puts the oil back in. Some have a five stage system with four scavenge pumps.

Here is a 4cyl with a dry sump.

http://www.pegasusautoracing.com/pdfs/056.pdf

I'm sure this kit could be adapted as well as individual parts selected from other sources to make it happen. Non the less it shows what the system looks like. The pumps need to mount low.
You can use a pump for another engine just expect to whip up your own mounts and drive system.

http://www.petersonfluidsys.com/pumpdry.html

You would have to block off the OE pump where the pickup bolts on. I suggest a pipe thread tap, brass (since were going in AL) pipe plug and sealant.

Since the passages the pump fed are still connected to the other side the pump gear will still get lube. I would leave both gears in it and drill a sizable port from the pickup side of the pump cavity to the output cavity so they spin in oil without actually pumping anything.

You can't eliminate the OE pump drive sprocket due to it's integration with the timing belt. You also need to get oit to the old pump to keep the sprocket bearing surfaces from running dry.

The best thing to do is just to get a two stage scavenge only pump. Then attatch a AN fitting to the OE pump passage where the pickup once bolted on. The OE pump will work fine especially if you mount the oil res above it. It will have a siphon effect in its pickup... Something it did'nt have in OE configuration.

It works for real g-am cup vettes so why go fancier on DSM's?

 

[Guerillah]

This guy did a custom dry sump setup on his mr2, he was in this years SCC USCC. Probably worth checking out. You'll have to dig around in there to see it.. http://www.trueleo.com/

 

[MNGSX]

Dry sump basics.
http://www.howstuffworks.com/question331.htm


As for the C5 example

Actually it is the grand-am street stock.

http://www.grand-am.com/grandamcup/comp_bulletin_01-2.html


5. Corvettes. Revision to read; dry sump oil system allowed with following requirements; must use OEM pressure oil pump with crankshaft driven two stage scavenge pump (maximum body width 1.400 inches) scavenging only the oil pan with a maximum line size of AN-12. Addition of crankshaft pulley drive allowed, harmonic balancer must have a steal hub (no aluminum hubs). The Oil tank is free. Technical Director must approve dry sump oil pan.



So take an extra oilpan and cut the deep end off but leave about 25% of the sump. Weld a windage tray or baffle above the sump. Then weld a new bottom to the pan.

Mount an AN bulkhead fitting to the pan. Near the pump.

Tap the OEM oil pump inlet where the pickup bolts on for an AN fitting. A short hose will connect it to the back of the bulkhead fitting. The outside fitting will go the the external oil tank.

Mount two AN-12 fittings for the scavenge system.

LS1 Dry.

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[hose101772]

Been looking at this for a while myself.Thought what if someone was to take a couple of whatever brand factory pumps runem all together-shaft to shaft to shaft-mount it in the block where the rear balance shaft was and power them from the remains of the balance shaft stub.Internal pickups routed to external tank/cooler via oil pan side, then back through the oil pan to the factory pump.This would do everything needed and use the factory timing belt.If the belt breaks you're screwed anyway.

 

[NosLaser]

Man, you guys sure do like to analyze stuff huh? Impressive for sure, but sometimes less is more.

Dry sumps will provide a very substantial power gain, especially when the power levels start to rise. But ask yourself this question. What do you use the car for? Is it primarily a street car? Are you planning to make over 600HP? The point I am getting at is it's an expensive process even if you do it yourself. If you just plan on having a moderately fast street car, then there are other much easier ways to go about making horsepower. My Mustang should make over 650 to the tires on pump gas, and I'm not even considering a dry sump. It's a bit overkill for most people's goals. When I had considered building up a Twin Turbo Vette/F-Body, I had plans for a dry sump number one for underhood space savings, and because the car would make well over 1100 wheel HP. A good way to determine whether or not you need some form of extra crank case evactuation is if after making a pass, your overflow bottle (assuming you have one) is filled with a substantial amount of oil. If not, you'll be spending a lot of money to fix something that isn't broke.

Regards,

 

[GTM]

Originally posted by NosLaser
Man, you guys sure do like to analyze stuff huh?

Hmmm that is very estute. You wanted to say something to impress us?

GTM

 

[babell2]

Originally posted by GTM
I have something in mind that may make it more practical and affordable than most realize if we can get some interest here to kick it around.

So Have we kicked it around enough yet? What's your Idea? Are you going to do It?

babell2

 

[NosLaser]

GTM,

Apparently you misunderstood what I was saying. That was meant as a compliment. I'll chalk that up to misunderstanding.

Regards,

 

[MNGSX]

Those who are good at fabricating looking for every bit of efficiency.. Then go for it.

I agree with the fact most mid to lower power level cars should get work elsewhere.

I do think it has it's place in a roadracing car where not only windage but lateral g's in differing directions make it a good idea. It aint like oval track where you can put a kick out on one side of the pan.

If you do it feed oil with the stock pump just extend the pickup line to the external oil tank and suck the case dry with a two stage scavenge pump..

 

[DSMJim]

Were putting a dry sump on our all motor honda and the pump is 3 stage. One for oil and two stages for vac all from one pump. The tank has a blow off valve on it for a situation where you blow a head gasket and pressure rises so it lest the pressure escape instead of blowing up.

Keeping the oil warm is hard so were acctually using a heater in the tank to warm the oil up. Startup at 160, warm in the lane till 220 then after burn out and sitting at the line its back down to 160. IT's almost impossible to keep the damn oil hot really. The whole setup cost $3000 parts only and obviously it's a whole piss load of work to install.

Leslie Durst the fastest all motor chick ther ran 9.93 and Z10 claimed she gained 41hp from going with a sump oil setup. That's pretty crazy.

 

[unior]

i have heard of our ps pump failing from blown seals...

 

[Eagle 5]

also with a dry sump systme, the oil is constantly moving, which in turn by keeping the oil moving it keeps it from ever sitting in one place, in turn means your oil will last a heck of a lot longer than 3000 miles. We use dry sump systems on jet engines because it keeps oil from coking anywhere and breaking down liek it does in a normal enigne. that is hwy on Porsche, you change your oil at 30,000 miles isntead of 3000. the oil is constntly moving, never sitting anywhere. so thats another benefit.

 

[Ajax]

here's a site that makes crankscrapers fot those (me) that dont have the money or the brains to go with the dry system, and still get some benefit.

http://www.crank-scrapers.com/