Oil issues: Dry Sump, Accusump for road racing?

[Sgt.Gator]

I don't think the broken A/C adjuster is the problem. I think I broke it after the track session when I tried to adjust the belt tighter but forgot to loosen the lock nut on the arm. It's a plastic and doesn't withstand much of that.

Bob, I can assure you it doesn't need to spin faster. Here's why: On Chad and my systems we use the stock crank pulley (5.5"). The pump pulley is 4", so we are already running the pump at 137% faster than crank. I thought "Eureka!" In all the literature the pump is supposed to run at 50% of crank, more than 5,000 rpm causes cavititation. Every image you see on the pump manufacturers websites show the crank pulley half the size of the pump pulley.

Well it turns out that doesn't apply to scavenge only systems, only pressure systems. The scavenge only can be spun at super high speeds and it's ok. I got that straight from John, the owner of Aviaid pumps. He says he's sold lots of pumps to Phil for the Element systems and never seen our problem.
So if anything the pump could possibly use a larger pulley to slow it down. A 6" would slow it down to 95% crank speed.

I went back and pulled a bunch of logs pre and post dry sump, which also is pre and post new shortblock/oem oil pump. I only have one log with the new shortblock and the wet sump:

The ORANGE lines are RPM, the BLUE lines are Oil Pressure, the Red Line is Oil Temperature.
Chronologically

May 2014, Wet Sump, 20 minute race in Spokane. Oil never goes over 186 degrees, oil pressure is flat 60-90 psi:




Sept 2014, wet sump, 3 laps in a 60 minute enduro at The Ridge. Each line is one of three laps:



June 2015, New Shortblock, New Oil Pump, Wet Sump. The first indication that my oil pressures are too high. After a warm up I hit the track and the oil pressures are too high for warm oil. Session cut short when vacuum line comes off EWG:




July 2015, DYNO session, New Dry Sump. Oil pressure is too high but oil temps don't climb because WOT is so short before long idle sessions during tuning:



And finally the track test as in the above post, but this one has RPM on it. Long warm up, normal oil pressures, but as soon as I hit the track with hot oil the pressures go too high and and the temps start climbing:




The problem with high oil pressures: Not only can it blow out seals and other damage, but the Subaru OEM Oil Pump Bypass opens at 95 PSI. That causes the same sample of oil to spin around and around in the pump, which according to John at Aviaid (who sent me down this course of investigation) that heats the crap out of the oil:



Conclusion: For some reason I'm having excessive oil pressures, causing the bypass to open, causing the oil to heat up. The oil is probably also cavitating because it keeps getting spun around and around in the pump.

Solution: New OEM Pump? Does it matter if I use a 10, 11, or 12 mm pump? Should I try an OEM pump modified for "high volume" or will that make it worse? I need your help!

The other solution is to add a pressure stage to the pump, which also means a new crank pulley and crank pulley mandrel and other bits like a remote oil filter.....and more $$$.

[Tamra]

You can add shims to the pump that will increase the bypass pressure. The 11mm pump bypasses at a lower psi so you'd have to add more shims to raise it. The smallest pump that meets your needs is the one you want, since a 12mm will bypass more than a 10mm, per my understanding.

I do not know much of anything about dry/wet sumps, so can't help you there.

Here's a quote from our own build thread from awhile back when we researched pumps after having <10psi idling pressure with our 10mm pump:

We picked up an 11mm brand new Subaru pump today. We checked the plunger for any burrs and sanded it with fine sand paper (known problem on the 11mm pumps - the relief valve can be stuck open from the factory), and also added 4 shims to increase the bypass pressure. The shims don't affect idle oil pressure, but they do increase the psi point in which the pump starts bypassing the oil pressure at higher RPM's, reducing the risk of aeration (leads to sudden oil pressure loss). The 11mm pump has an oem 75psi bypass (vs 85 for the 10mm), and the more shims you add the higher the psi has to be before the bypass opens. This puts more pressure on the system overall, but with our high rev goals, it makes it safer and decreases the risk of aeration.

We decided against the 12mm pump because we read that it actually drops off over 6500 rpm (meaning the 11mm flows more oil than the 12mm after that point). We haven't seen any data on exactly how much each shim increases the bypass psi, so we are hoping/guessing that 4 is about right. Most people do 3, but with us increasing the red line, we figured 4 would be better.

We did not expect to see our oil pressure increase from <10psi to 25 psi. Our suspicion is that either our relief valve in the 10mm pump was stuck open (although upon inspection it did not appear to be stuck), or that our 10mm pump was just worn out (donor car). The 11mm pump should not have increased our idle pressure that much. Regardless, it is better now!

[Mitch Wright]

We had a similar but different issue years ago with Datsun L series engines, the pressure relief valve was stuck in a batch of OEM oil pumps. What we would see was extremely high oil pressure at start up. Once we cleaned up the plunger so it wouldn't stick we would then shim (preload) the spring to get the oil pressure to the 70lb we wanted at 8000rpm hot. I am still a ways away from having any track data that is helpful. I am running the stock 2L WRX Subi pump for my 2004 engine, talking to the guys at Moore Performance in Pittsburgh felt it would fit my application. Now at that time I was planning on a KB pan, that has since change to a Dry Sump. Got some great info from John at Aviaid and a path to investigate.
More questions on which is the pump to use?? I get the frustration and been there many times on other projects but I find the investigation and finding the solution challenging fun.
I have a buddy who is good friends with Gary at ARE, when he (Gary) gets back from vacation I am going to pick his brain as well.
I see some good news and think you and Chad are zeroing in on the real issue.

[Sgt.Gator]

This post on Nasioc from KillerB to a member with too high oil pressures:

"Go back to a 10mm pump. The 11mm pushes ~36% more flow and unless the engine was built specifically for that you're pushing it into a wall... The bypass is made to flow x amount of oil based on the pump that is suposed to be based on the engine. So, an 11mm pump can cause pressure spikes leading to seal failures. In addition to adding excessive heat into the oil from continuously recirculating significant flow through the bypass all the time, but that's not the worst. Worse case you bypass a LOT and because the flow characteristics through the bypas are so terrible, you aerate the oil, which means aerated oil gets pumped into the bearings and air definitely does not lubricate as well as oil.

Also, for reference the 10mm pump flows less but at a higher 85psi and the 11mm flows more, but at a lower 78psi.



Edit: Don't even think about the JDM 12mm It's made for the Spec-C/WRC engines that have MUCH better crank rod oiling (and other bits) and 8K RPM rev limit from the factory."

I put the A360 pump in my new shortblock. I guess I'll try the A300.

A lot of good info in the thread quoted above, especially page 3, post 56 from KillerB about shims and flow: http://forums.nasioc.com/forums/show....php?t=2466900

[C.Plavan]

99.9% sure I have a 10cm oil pump. AJW stripped a 2006 wrx motor and threw everything on my 2013 wrx STI block.... Everything- td04, injectors, wiring harness everything. I never got a bill for a new oil pump (11cm). I'm not home, is it easy to see the part number on the pump?

[Sgt.Gator]

I would be REALLY surprised if they reused a 2006 oil pump. I don't know how to ID them once they are mounted though. You have to pull the timing covers off just to see it.

Do you have logs of your oil pressures? If you're oil pressure is not high, this won't help.

Edit: It appears 10MM pumps have a 10 in the upper left outer cover, 12MM have a 12, and 11MM have the number 76 or 78.
Makes sense to me!

[C.Plavan]

If you ever bought anything from AJW, you would understand. I replaced a lot of things on the motor before installing it....

My pressures are 80 to 85psi when warm another reason I'm almost positive I have the 10cm

Thanks for the tip on the numbers. I'll check when I get back Friday.

[Mitch Wright]

Great info

[Sgt.Gator]

A couple of additional thoughts:
The 11MM pump was developed to support the oil flow to Dual AVCS, which I don't have.
The factory specs also include using a journal bearing turbo. I have an upgraded ball bearing turbo which comes with an oil restrictor, again using less oil flow than the factory system.
And I'm using a factory oem shortblock, not a built block with looser specs.
I speculate that those three things are enough to cause the oil pressure to be too high on an 11mm pump.
Bigger is not always better!

[FFRSpec72]

A couple of additional thoughts:
The 11MM pump was developed to support the oil flow to Dual AVCS, which I don't have.

My JDM EJ207v7 has a 12mm pump stock (high revs). Also you should be getting your car ready for Pacific Raceways this weekeend !

[Sgt.Gator]

My JDM EJ207v7 has a 12mm pump stock (high revs). Also you should be getting your car ready for Pacific Raceways this weekeend !

Yes I should, but instead I'm hoping to get enough done to go up to ORP for an ORP Club track day on Sunday. I can't afford to keep paying race registration fees, hotel rooms, and long tows to run 15 minutes and discover my car is overheating again. No more races until I can run an all day track session with no problems!

PIR is my next shot at being back in the races, August 21-23. I hope to see your 818R there!

[C.Plavan]

Yes I should, but instead I'm hoping to get enough doen to go up to ORP for an ORP Club track day on Sunday. I can't afford to keep paying race registration fees, hotel rooms, and long tows to run 15 minutes and discover my car is overheating again. No more races until I can run an all day track session with no problems!

Welcome to my world since January

[Sgt.Gator]

Welcome to my world since January

Maybe we should trade cars for a weekend!

[C.Plavan]

I stuck my finger down on the upper left of the oil pump and pressed hard. .1%

I have a 11mm (78 backwards on my finger)

I'm wondering if I can change the oil pump in the car.

[Scargo]

Chad, Perhaps you could decipher what you just said?

[C.Plavan]

Chad, Perhaps you could decipher what you just said?

I was 99.9% sure I had a 10cm pump, the .1% proved me wrong. I have an 11cm oil pump (cast 78 in upper left outside of oil pump) if it was a "10" it would of been a 10cm pump. for some reason, the 11mm oil pump has a 78 mark. My mechanics mirror broke, so I just stuck my finger down there and pushed hard so the indentation of the casting mark showed up on my finger...... plain as day "78" (backwards of course)

I just ordered a 10cm oil pump for $126. I'm hoping I can change the oil pump in the car without pulling the motor.

[Wayne Presley]

You can change it in the car

[Scargo]

Though I'm just guessing, I would think pulling it/tranny would end up being less nerve-racking.
Having said that, I can't imagine you going to a 10. What makes you want to do that? Less volume? Perhaps if bearings/journals, etc. are really tight but seems like (from all I've read) and my personal experience, that the 11 rules race motors.

[C.Plavan]

You can change it in the car

Thanks Wayne. I'll give it a shot.

Though I'm just guessing, I would think pulling it/tranny would end up being less nerve-racking.
Having said that, I can't imagine you going to a 10. What makes you want to do that? Less volume? Perhaps if bearings/journals, etc. are really tight but seems like (from all I've read) and my personal experience, that the 11 rules race motors.

We both have stock tolerances. The 11cm pump is definitely not working for us. Hopefully going to a 10cm with the Spintric Air/oil separator will work wonders. We have to try something.

[Tamra]

Glyn, read above to the info Gator and I and others posted. There are many reasons a 10 can be better (less oil bypassing is primary benefit. The 11mm bypasses at 75psi. When it starts bypassing, oil heats up and you also risk aerating the oil. The 10mm bypasses at 85psi and since it is pumping less it is less likely to cavitate). As long as the 10mm can keep up with his oiling needs, then it is the best choice. Smallest pump that meets your needs = best. Considering Chad's problems it seems like a good idea.

Chad, we swapped the oil pump in the car. You'll have to remove the seats, the firewall, and the timing belt to access it. You can leave the fuel tank most likely.

While you're at it, you might want to consider adding shims to raise the bypass. Also, check the movement of the piston (and possibly some super fine sand paper on the piston to make sure it doesn't have any burs to hang up) before you install it. There have been instances of them getting stuck in bypass mode if there's a bur.

[C.Plavan]

Gator do we want to shim the 10cm? I'm thinking not since the lower flow, higher pressure compared to the 11cm we have. I can't think, I just got back from 4 days in Vegas.

[Bob_n_Cincy]

I stuck my finger down on the upper left of the oil pump and pressed hard. .1%
I have a 11mm (78 backwards on my finger)
I'm wondering if I can change the oil pump in the car.

Chad
all the pumps are 78mm rotors, How do you know you have a 11mm.
Am I missing something here?


Bob

[C.Plavan]

Chad
all the pumps are 78mm rotors, How do you know you have a 11mm.
Am I missing something here?


Bob

Read post 126 by Gator. They have identifier on each pump.

[Scargo]

There are many reasons a 10 can be better (less oil bypassing is primary benefit. The 11mm bypasses at 75psi. When it starts bypassing, oil heats up and you also risk aerating the oil. The 10mm bypasses at 85psi and since it is pumping less it is less likely to cavitate). As long as the 10mm can keep up with his oiling needs, then it is the best choice. Smallest pump that meets your needs = best. Considering Chad's problems it seems like a good idea.

"As long as the 10mm can keep up with his oiling needs" is the key phrase. What you're saying may be so, but are you talking a stock motor or what level of modification and power? What kind of racing?
I am concerned with the rigors of extended racing, heat generated-building up and oil thinning. What about when you add an external oil filter, oil cooler(s), valves, tanks, and long hoses to put it all together? There is pressure drop from all that. I'm well aware of recirculating through the bypass as being problematic. You can benefit from cleaning up the pump internals and improving the flow in the engine's passageways. All mine have been radiused, enlarged and smoothed.
I don't think the 11mm pump is the problem. I know too many people using them in track motors.

[C.Plavan]

Clearly the 11cm pumps are not working, so I don't know what you are trying to say.

[DodgyTim]

I can't get my head around why this is happening to the dry sump cars unless it is a scavenge issue leading high oil level inside the motor.
I've seen it written on other forums that the oil (from the bypass) recirculates around the pump, but in other places I've seen it writtten that it recirculates to the sump.
If the oil bypass goes to the sump a smaller oil pump may definitely help: oil volume needing to be scavenged (oil used by the motor + bypass oil) would be less
Edit: it appears to circulate the pump only
5212010_101228%20PM.jpg

[Scargo]

I may have missed something, but I don't see how you can say that "clearly the 11mm pumps are not working". As I say, I have my track motor in the STi (and lots of hours on it) and a lot of friends with Subie track cars. I have that anecdotal and experiential evidence that the pump does work with cars with similar or lesser setups. It is a very "standard" pump to run in a built motor.
I'm hard-pressed to see how dry-sump affects the choice of pump.

[DodgyTim]

.
I'm hard-pressed to see how dry-sump affects the choice of pump.

Only that this specific system uses the oem pump for oil pressure to the motor, and the dry sump pump to remove it. The second one has to flow more than the first one

[Bob_n_Cincy]

I went back and pulled a bunch of logs pre and post dry sump, which also is pre and post new shortblock/oem oil pump. I only have one log with the new shortblock and the wet sump:

The ORANGE lines are RPM, the BLUE lines are Oil Pressure, the Red Line is Oil Temperature.
Chronologically

May 2014, Wet Sump, 20 minute race in Spokane. Oil never goes over 186 degrees, oil pressure is flat 60-90 psi:




June 2015, New Shortblock, New Oil Pump, Wet Sump. The first indication that my oil pressures are too high. After a warm up I hit the track and the oil pressures are too high for warm oil. Session cut short when vacuum line comes off EWG:

.

Sgt.Gator,
In the 2 graphs above they are both wet sumps. But the second has unstable oil pressure.
In my mind the only two ways to get to 160psi.
1. sticky pressure relief valve.
2. there is so much extra oil flowing that the relief valve is wide open but can't handle all the extra oil.
Is it possible that there is a batch of oil pump out there that you and Chad both got a bad one.
Bob

[Sgt.Gator]

Chad, that's an interesting way to check!

At least you know now what might be the problem....I have my new 10MM in and am headed to ORP in the morning. It will be 100 degrees there. This will be a good test and I'll let ya'll know right away when I get back the results.

I didn't shim it.

Bob in the two graphs above the May 2014 was on my old 2005 shortblock with a 10MM pump. The one with the insane high pressures is the new oem shorblock EJ257 with the 11 MM upgrade pump.

Fingers crossed.

BTW, I think all the street guys never see this issue even with 350HP oem block street machines because they don't drive around for 30 minutes at WOT. If you look at my Dyno the oil never gets hot because it's a quick pull then a few minutes of idling, despite the crazy high oil pressures.

Another comment I saw on this, a regular oil pressure analog gauge won't catch the crazy high points, they happen too quickly. Only with a fast datalogger like my AIM MXL will you capture it. The analog gauge will show the overall average too high pressure though.

Scargo this doesn't usually happen to high HP forged builds because of the looser tolerances most builders use.

We'll know Friday by Noon!

[C.Plavan]

Chad, that's an interesting way to check!

At least you know now what might be the problem....I have my new 10MM in and am headed to ORP in the morning. It will be 100 degrees there. This will be a good test and I'll let ya'll know right away when I get back the results.

I didn't shim it.

Bob in the two graphs above the May 2014 was on my old 2005 shortblock with a 10MM pump. The one with the insane high pressures is the new oem shorblock EJ257 with the 11 MM upgrade pump.

Fingers crossed.

BTW, I think all the street guys never see this issue even with 350HP oem block street machines because they don't drive around for 30 minutes at WOT. If you look at my Dyno the oil never gets hot because it's a quick pull then a few minutes of idling, despite the crazy high oil pressures.

Another comment I saw on this, a regular oil pressure analog gauge won't catch the crazy high points, they happen too quickly. Only with a fast datalogger like my AIM MXL will you capture it. The analog gauge will show the overall average too high pressure though.

Scargo this doesn't usually happen to high HP forged builds because of the looser tolerances most builders use.

We'll know Friday by Noon!

Good luck! Post after the first session if you can.

[Sgt.Gator]

Good luck! Post after the first session if you can.

FAIL!

Oil pressures still too high. Oil temp follows it up. So it's not the 10MM vs 11MM pumps.

I have learned a couple of things:
The oil pressure is fine under 2000 RPM. At 2000 and above the pressure soars. I idle in the paddock all morning and oil pressure will level out when the oil temps reach 180. As soon as I rev the engine above 2000 the pressures go crazy high. Back under 2000 the pressure is normal. Then go out on the track revving to 6K oil pressure goes nuts and temps will follow in 10 minutes. Pull back into the paddock with oil at 260 degrees, hold the throttle at 1500 RPM, the pressure goes back to a solid 50-60 psi, and temps drop pretty quickly.

So what is happening at 2,000 RPM to cause a dramatic change in oil pressure?

The obvious test is to disconnect and plug up the dry sump, put the wet sump pan in, and see what happens. Now I know I don't need to go to the track, I can do this test in my garage.

But swapping the pans is a pain. I may have an easier test. Disconnect the pump and tank lines. Put the former scavenge lines into a bucket of oil just below the engine. Put the line that feeds the oem pump into the bucket. Effectively creating a wet sump "pan".

Run the engine and see what happens above 2,000 RPM. If oil pressures are normal it's definitely something about the way the dry sump is working.

I'll edit this post later with the data log graph.

Sorry Chad, we still have work to do!

[C.Plavan]

Boooooooooo. Well, I'll keep the 11cm pump in there for now and see if it is aeration in the oil after I install the Spintric. My oil pressures are not getting as high as yours on the gauge. But I'm not data logging it.

But aeration would cause the pressure to go down.... So confused.

[Tamra]

Reading your data logs above, I see that your wet sump was working great (in terms of oil pressure/temp) and then you put in a built short block and new oil pump, and your oil pressures spiked. You then switched to the dry sump and problem continues. You tried the smaller pump today and eliminated it as the problem. It seems to me that what's left is something with the built short block. Did you change the bearing clearances? Did you change the turbo? Did you change anything like avcs?

[Sgt.Gator]

Reading your data logs above, I see that your wet sump was working great (in terms of oil pressure/temp) and then you put in a built short block and new oil pump, and your oil pressures spiked. You then switched to the dry sump and problem continues. You tried the smaller pump today and eliminated it as the problem. It seems to me that what's left is something with the built short block. Did you change the bearing clearances? Did you change the turbo? Did you change anything like avcs?

OEM shortblock, not built. Straight from the Subaru parts bin. The car is setup exactly the same as before.
I'll try the wet sump bucket experiment this weekend.

The only other "fix" that I can think of is a larger pulley on the pump to slow it down. No other users have needed it though.

[walt555]

FAIL!

Oil pressures still too high. Oil temp follows it up. So it's not the 10MM vs 11MM pumps.

I have learned a couple of things:
The oil pressure is fine under 2000 RPM. At 2000 and above the pressure soars. I idle in the paddock all morning and oil pressure will level out when the oil temps reach 180. As soon as I rev the engine above 2000 the pressures go crazy high. Back under 2000 the pressure is normal. Then go out on the track revving to 6K oil pressure goes nuts and temps will follow in 10 minutes. Pull back into the paddock with oil at 260 degrees, hold the throttle at 1500 RPM, the pressure goes back to a solid 50-60 psi, and temps drop pretty quickly.

So what is happening at 2,000 RPM to cause a dramatic change in oil pressure?

The obvious test is to disconnect and plug up the dry sump, put the wet sump pan in, and see what happens. Now I know I don't need to go to the track, I can do this test in my garage.

But swapping the pans is a pain. I may have an easier test. Disconnect the pump and tank lines. Put the former scavenge lines into a bucket of oil just below the engine. Put the line that feeds the oem pump into the bucket. Effectively creating a wet sump "pan".

Run the engine and see what happens above 2,000 RPM. If oil pressures are normal it's definitely something about the way the dry sump is working.

I'll edit this post later with the data log graph.

Sorry Chad, we still have work to do!

Does the crazy oil pressure sound like the pressure regulator in the pump is stuck?

[Sgt.Gator]

Does the crazy oil pressure sound like the pressure regulator in the pump is stuck?

The probability of both a new 11MM and a new 10MM both having that problem is extremely small.

[Bob_n_Cincy]

This problem is driving me crazy, and I don't even have it.
I didn't read this anywhere, or have any supporting data, so take it how you desire.

On thing that is special on this dry sump system is that it uses the existing engine oil pump. The pumps intake hose is maybe 4ft long running to the bottom of the sump tank. During high usage (high rpm & hot thin oil) the pump has to suck a lot of oil through the 4ft hose.

Hydraulic pumps systems are great at pushing fluid. But on the suction side of the pump. It is really the ambient air pressure in the sump pushing the fluid to the pump. If the pump is pushing oil faster than air pressure can push it in the hose vacuum void will occur in the 4 ft pipe. Every time a void gets to the pump, this could be the cause of the unstable pulsing of the pressure.
Does this make sense?

Bob

Chad and Sgt.Gator, Can you post a sketch of your systems showing where your filters and coolers are in the circuit.

[C.Plavan]

The hose from the bottom of my tank is about 3 feet long that goes to the dry sump plate (pump). That is the only suction. The coolers, filter (stock) is all "push" back to the tank.

[DodgyTim]

Gator, same sensors used in all data logs? New motor didn't come with a new sensor?