Oil issues: Dry Sump, Accusump for road racing?

[EODTech87]

I was the one that asked. Came across a killer deal on the dry Sump but I decided against it because of fitment issues. I didn't see it fitting because it appeared to stick out to much. Glad I did with it being almost 2"

[Mitch Wright]

Guys I know i have gone rouge here running my wet sump system on my 818R. I data log oil pressure, oil and water temp intake air temp at the throttle body, RPM, speed and G's. I am not seeing any fluctuation in oil pressure during a on track session. With the oil temp at 220* (currently running the OEM oil to water heater), water temp 176* at idle op is 56-58 psi and 75-78psi under load. The graph line is flat under accelleration, braking or 1.6 g corner load it doesn't change. I also am not seeing any knock at all.
I am not saying a DS system is not a good thing, I think they are great. But it looks to me with the data I have on my car a wet sump can do the job. I am running KB pan and windage tray, Crawford Air Oil Separator, KB Oil Control valve and Separator, Mobil One 5-50 Racing oil. I always pull my TMIC looking for oil in the intake system, it is dry. So all I can say is so far this combination is working on my track car. (the engine has 100K on it as far as I know)
this also has me wondering if some of the engine failures are due to detonation or some other tuning issue? I am also not making big HP I am running sub 300WHP

[Hindsight]

Mitch, great to have your data point! I have often wondered the same.... if some of these failures are not due to something else. I know pickup tube failure is common on some models, and I also wonder if people are keeping their oil all the way to the full line or a bit beyond. I hope you keep the wet sump on there and run for a good while like that so we can all learn from it. Are you running the KB pickup? You mentioned pan and tray but not pickup.

[Scargo]

... at idle op is 56-58 psi and 75-78psi under load.
That OP is is quite good. What oil pump? Shimmed? Where are you measuring the oil pressure?
You mentioned 100K on engine. Internals? Did you mod anything?

... 1.6 g corner load it doesn't change...
Sustained for what maximum time interval?

I am running KB pan and windage tray, Crawford Air Oil Separator, KB Oil Control valve and Separator, Mobil One 5-50 Racing oil...
You have all the good stuff! I have almost the same setup on two cars now except for KB's new valve. You are proof of what Chris of KB claims. I just wonder where the G threshold is? It is sustained high G's (along with poor oil control) that seem to be the achilles heel of these engines.

...this also has me wondering if some of the engine failures are due to detonation or some other tuning issue? I am also not making big HP I am running sub 300WHP
What RPM's do you use? That power level is a piece of cake for a decent motor.

I am building a sub-500 CHP engine right now for my new DD, where I have concentrated on the oiling system, breathing and balancing. Nothing wild and crazy (to me). 11mm ported and shimmed oil pump. External filter and cooler. Racing tolerances of .0015"/.002" while running a loose stock bore, and very light internal components. Aiming for a few more R's rather than HP. That is why I have a de-stroker motor on the shelf for my 818R.

[Mitch Wright]

Hindsight,
I plan to run the wet sump until it proves to be a problem, i also have a few tricks to try that i got from some folks in Europe. The oil pick up is also KB


The long block is as it came out of my donor, it had really good compression so freshened up the heads new timing belt kit and removed the TGV's. As far as I know the pump is what came in the engine when new (04 EJ205) Other than the TGV delete, clean up the port pockets and change to a JDM header and Twin scroll VF37 Turbo are the only engine mods, I did not shim the oil pressure relief valve. At 14psi of boost 256WHP and 18psi 285WHP I had Corbin set the rev limiter to 7100, very rarely do I run it past 6900.

NCM MSP has 2 long fast right handers (in the 818 they are 100mph+) 1.6G is the peak but 1.4-5 is sustained, 3 long medium speed right handers and 3 medium speed lefts and 1 fast left. When at work tomorrow I will take a look at how many seconds I see over 1 G and 1.4G I will post screen shot
Chris and I have spent a lot of time discussing ideas on what is need to make a wet sump work, also pick the brains of the guys at Moore Performance, Strker and a another team in Germany that I can't recall their name.

[Scargo]

Thanks! All great info! I'm curious about what the Germans shared unless you are sworn to secrecy.
It's interesting that Chris, of KillerB, is good about making himself available to customers by phone or forums. We have had many exchanges on NASIOC and I have met him. A good friend and track companion had an issue with a KB header and Chris made it right. That said, I like most of his products. Watch their thin SS baffle plate, as my friend has just had one stress fracture in multiple places and almost fail completely after three years of heavy track use.

[Hindsight]

Those are good oil pressures by the way. I'm seeing as low as 65psi on the track when my oil temps get up to 240 degrees. If I hit those temps, I back off a bit until they come back under control.

[Sgt.Gator]

Mitch that's good news. I hope it works for a long time for you!

Here's an awesome Time Attack build, Mark Jager's Redline Time Attack car. He went thru 4 engines in 2015....and another at the start of 2016. Now he's made some changes. I don't know how many were oiling issues and how many just couldn't take the extreme power. But note he has an ARE DS system now.

http://blog.jepistons.com/car-featur...attack-wrx-sti...

[Mitch Wright]

Sgt Gator,

I hope it works for a long time too.

That is a trick looking piece, We have a guy with an Evo that does the USCC series, I would guess he is making 500 plus hp and has gotten really good at changing out broken engines. I just want my engine to start when I push the button and make enough power to have some fun.

You had asked where I am taking oil pressure from, I have the sender in the back of the block off the passage next to the crankcase vent.

EJ Oil Pan Baffle.jpg here is a photo of the baffle they are sandwiching between a Cosworth style pan and windage tray that is similar to KB. I have made this baffle but have yet to install it.

[Sgt.Gator]

I have a couple of Cosworth Baffle plates that I bought used from Vermont Sports Car (the Subaru Rally Team USA). If anyone is interested PM me, I'll be putting them up in my eBay store soon.

I met the D Sport magazine folks at SEMA and subscribed to their print magazine. They cover the import market.

Here's the online version of one of their recent magazine articles, it's worth reading.

Subaru EJ257 Bottom-end Breakdown
http://dsportmag.com/the-tech/subaru...end-breakdown/

And stop the insanity!



Roger Clark’s Sons Set Records in 880hp Time-Attack Gobstopper II STi
http://dsportmag.com/the-cars/roger-...me-attack-sti/

and same car:

http://www.speedhunters.com/2017/03/...ed-final-form/

You can see what I'm assuming is a dry sump at the bottom of the engine in this image;

rogerclarkmotorsport-2017-jordanbutters-speedhunters-160.jpg

[Mitch Wright]

Thanks for the DSPort article, interesting.

[Sgt.Gator]

Here's an update on how my Cosworth DS is doing in my 2005 STI:
2 track days at ORP + 1 race weekend at Spokane. No issues!

At the ICSCC race in Spokane last weekend I ran in the ST sprint race, but more importantly two 1 hour Enduros. The second Enduro was in 90 degree heat. Oil pressures were rock solid strong even at the highest temps seen. I'm using a Cosworth modified OEM pump. Oil temps were amazingly low as long as I remembered to turn the Derale oil cooler fan on. Without the fan they maxed at 240, with the fan on they stayed at 200. If I short shifted and took it easier for a lap they would drop to 180-190 very quickly. Coolant temps also stayed in the lower half of the oem gauge.

Oil is Valvoline Racing 20W-50 Conventional. It's pretty cheap, less than $5/Qt on sale and is available at most regular auto parts stores.

I don't have a vacuum gauge on the crankcase yet so I can't comment on how much vacuum it's seeing. And since I'm running a sealed system with a vacuum relief valve there is no blowby/AOS issues to deal with. Eventually I'll add a vacuum gauge just out of curiosity.

Since this setup is very similar to the Element Tuning/Aviaid style setup with the exception that the DS pump is driven off a small mandrel on the crank pulley so the DS pump is turning at about 1/2 crank rpm, I am even more convinced that the Element Tuning type setup needs a underdrive crank pulley and an overdrive DS pulley to get the DS pump speed down.

And on a side note: I added a tranny cooler to my STI 6 speed by tapping the pre 2008 internal tranny oil pump to send the tranny oil to a cooler mounted up front. In my LGT Wagon racer I was never able to get tranny temps in the range I wanted after I swapped in a JDM STI 6 speed, they were hitting 260-265+. Tranny temps with the previous 5 speed were not an issue because the Subaru Road Race Team ( Joe Aquilante at Phoenix Performance) had installed a cooler and temp sender. My attempt to match what Joe had done with the 6 speed tranny was a fail. That was with a external pump. With my new setup in the STI they maxed out in the Enduro at 180. Perfect!

The 6 speed there is an easy place to install a temp sender. There's a 1/8th" BSPT fitting on the driver side front of the tranny you can insert a 1/8" NPT sender into. Since it's slightly different threads you'll need thread sealant on it and I wouldn't take it in and out. Just put it in and leave it. (Edit: removed reference to 5 speed for the 1/8" temp sensor port)

[RetroRacing]

Great news, and great seeing you at the track! We only had our RX7's out, but still had a blast (set two new track records for EIP) for race and quali in the low 33's. Can't wait to see what the 818 will do there, starting work on her again next week for a test in August.

[Sgt.Gator]

Great news, and great seeing you at the track! We only had our RX7's out, but still had a blast (set two new track records for EIP) for race and quali in the low 33's. Can't wait to see what the 818 will do there, starting work on her again next week for a test in August.

it was great seeing the Retro Team again. Are you coming down for the Rose Cup Races next week? I think Tony will be there in his 818 and I'll have the STI in RC2.

I have a new video/data system, Racelogic Video Vbox. The Video Vbox makes it easy to export any particular lap for sharing. Here's my fastest lap of the weekend, during the Enduro race:



Gator Fastest Lap at Spokane Enduro

I'm working on a better format. The new one will have the PIP in the upper part of the screen so it's easier to see where the car is on the left side and the units will be MPH, not KPH.

[FFRSpec72]

Great lap ! I was there 2 weeks prior when we had a driver killed on the back straight, really sad day.

[Hobby Racer]

For both the 5 speed and 6 speed there is an easy place to install a temp sender. There's a 1/8th" BSPT fitting on the driver side front of the tranny you can insert a 1/8" NPT sender into. Since it's slightly different threads you'll need thread sealant on it and I wouldn't take it in and out. Just put it in and leave it.

I plan to put a trans cooler in my 5MT. Do you have a pic of the BSPT fitting you are taking about, I can't seem to find it on my trans!

[Bob_n_Cincy]

I plan to put a trans cooler in my 5MT. Do you have a pic of the BSPT fitting you are taking about, I can't seem to find it on my trans!

You will have to add a pump to the 5MT.
Bob

[Sgt.Gator]

Great lap ! I was there 2 weeks prior when we had a driver killed on the back straight, really sad day.

Yeah they told us about the death at the driver's meeting. Very Sad. I'm sure it was horrible being there.

I plan to put a trans cooler in my 5MT. Do you have a pic of the BSPT fitting you are taking about, I can't seem to find it on my trans!

I still have my LGT 5 speed in the garage, I'll take a pic tomorrow.

You will have to add a pump to the 5MT.
Bob

Correct. Or if he monitors his trans temps with the sensor he may not need a cooler for the typical 30 minute race or hpde.

[Mulry]

Correct. Or if he monitors his trans temps with the sensor he may not need a cooler for the typical 30 minute race or hpde.

For future reference, I've found a thermal switch to be useful to prevent having to actively monitor temps on supplemental coolant circuits, something like this:

https://www.pegasusautoracing.com/pr...sp?RecID=10285

It's a little trickier to use with a pump because you might not achieve accurate temps until the pump is actually running (catch-22!) versus having it inline in a remote oil filter/cooler setup where the oil is constantly flowing already. But you can simply wire that to the ground side of the control circuit on the relay and run the relay high-current power to the pump (or a fan) and not have to have one more switch to worry about flipping while trying to concentrate on the driving.

[Sgt.Gator]

Mulry I have the Setrab 200 switch to control my Derale Oil Cooler fan next to the dry sump tank. It works well.

What I meant in my post to Hobby Racer was that he doesn't necessarily need to install the pump and cooler yet. He can install the temp sensor / gauge and if it shows he never gets too hot then he doesn't need to install the all the plumbing. If he's running max 30 minutes events he may not heat up the tranny oil, although I did with my 6 speed trans even in 30 minute races.

So I've gone crazy trying to figure out how I had the temp sensor in the 5 speed hooked up! I don't have any pics of it and I can't find where I thought it was on the 5 speed. It's possible I was confused with the 6 speed banjo bolt that has the 1/8" plug in it. Sorry about that. They must have had the temp sensor in the transmission oil cooler line.

[Hobby Racer]

So I've gone crazy trying to figure out how I had the temp sensor in the 5 speed hooked up!

Glad I'm not missing something obvious! I think I'm going to remove the drain plug and put in a Tee fitting so I can hook up my temp sensor and then plum the the other branch to the external pump.

[Mulry]

Just wanted to cross some information over into this thread as it's germane to the oil sump discussion. The Canton 22-597 remote oil filter adapter will work on the stock oil filter location on the EJ205 block with the stock oil cooler removed. The adapter is female threaded, as is the block, so you also needs an M20x1.5 union bolt to connect the two. Here is the link to the Canton adapter, I got mine from Summit:

https://www.cantonracingproducts.com...ion&key=22-597

The metric pipe fitting was harder to find, but this is the one that I got from Discount Hydraulic Hose, part 9001-20-20:

https://www.discounthydraulichose.co...ric_p/9001.htm

Big huge thanks to Bob_n_Cincy for supplying the info about the Canton unit!

[Scargo]

Just wanted to cross some information over into this thread as it's germane to the oil sump discussion. The Canton 22-597 remote oil filter adapter will work on the stock oil filter location on the EJ205 block with the stock oil cooler removed. The adapter is female threaded, as is the block, so you also needs an M20x1.5 union bolt to connect the two. Here is the link to the Canton adapter, I got mine from Summit:

https://www.cantonracingproducts.com...ion&key=22-597

The metric pipe fitting was harder to find, but this is the one that I got from Discount Hydraulic Hose, part 9001-20-20:

https://www.discounthydraulichose.co...ric_p/9001.htm

Big huge thanks to Bob_n_Cincy for supplying the info about the Canton unit!

The Canton 22-597 is what I and others use on our STi's to route hoses to go up the face of the timing cover to remote oil components. You may find that a minor bit of grinding on the cover is required and you want to use the smaller hex-sized 10-AN to 1/2" NPT fittings if possible for better clearance/fit.
Note: Be very careful not to overtighten the Canton adapter. If you tighten too much it will squeeze out some of the square seal and tear it as it extrudes it. Tighten the big nut much like you would tighten an oil filter. Also of note is, I haven't found another adapter that sits up as high as the Canton. You need this height for the fittings to clear the cover.

The union fitting you mention is a standard Subaru part and also sold on Ebay and elsewhere and also sold as a cheaper non-OEM fitting. Often referred to as a "Subaru Oil Cooler Delete Fitting" it is a "union, oil-pump", #15018AA090.
Oakos has a good price.

[Mulry]

Those are good tips. Wish I'd known about that Subaru fitting, it was a real PITA to find one otherwise.

I ordered our drive mandrel, oil drive pulleys and belt yesterday. We will do test fitment the weekend after next before we send out the custom oil pump mount for CNC milling. At some point, I'll do a full writeup on our system -- once we've confirmed it works

[Scargo]

... At some point, I'll do a full writeup on our system -- once we've confirmed it works

Glad to help.
Other related posts: http://thefactoryfiveforum.com/showthread.php?20279-Removing-Oil-Factory-Oil-Cooler&p=229350&viewfull=1#post229350
Pictures of Canton adapter installed.

I know what you mean about telling the world about what you've done before you've proven it out.
On NASIOC (where I'm Scargod) I've discussed installing a Peterson external oil pressure relief valve.
This was after I've put 15+ hours on this setup. That might be of interest to this group/discussion. However, some have expressed concern about aeration but I've had nothing but good results from it and I run either 430 or 470 at the wheels and up to eight grand on this oiling system. It could be if you plumbed it differently you might have an issue or if you used a different oil pump that you might have an issue. So, use at your own risk but it's worked for me and I am about to duplicate it on a EJ255 build but with an 11mm pump.

[DanielsDM]

Mulry,
IIRC you're running an external pressure pump (scavenge and pressure in 1 housing). If so it will have an adjustable bypass setting so I don't think an external relief valve is necessary. I don't intend on running one, but my setup isn't proven either so we'll see what it needs when I actually get it on the track.

Thanks for the info Scargo.

[Mulry]

You're right, we're running an external pump with 2 scavenge stages and one pressure stage, in no small part so that we can regulate the pressure via the bypass setting. I certainly hope I don't need to add one more expensive piece to this puzzle, but who knows at this point.

[Scargo]

Mulry,
IIRC you're running an external pressure pump (scavenge and pressure in 1 housing). If so it will have an adjustable bypass setting so I don't think an external relief valve is necessary. I don't intend on running one, but my setup isn't proven either so we'll see what it needs when I actually get it on the track.

Thanks for the info Scargo.

You (and all) are welcome. I hope I am being helpful... To be clear, I was not talking in the context of using it with a DS system but about my track STi. With my top-heavy beast I cannot generate 818 G's and do fine with a Killer B system and good blowby management.
It could be used with a pieced-together DS system where you are adding a scavenging system, tank and pan.

[Sgt.Gator]

From PRI 2017: I had a great talk with the owner of the Can Jam Motorsports STI, Nick Hoo, that just won the Speedring 2017 Time Attack overall fastest time and earned them a $20K check from Motovicity. It was very interesting. First a few shots of his car:



I think the splitter needs to be a little larger....



Murray Constant Tension Turbo Clamps!...Yes, I sell them, how many do you want? Shameless Vendor Plug.




OK, so where's the Dry Sump? There has to be one in here somewhere.....



The answer is there isn't one <now>.

Like all Subaru racers that get into High G's Nick suffered several oil related engine failures from the heads filling with oil. That led him to use what most of us consider the cream of the crop DS, the Dailey. However, they still weren't getting the longevity they expected. They noticed a slight drop in oil pressure under hard accelration. 600HP and AWD will get you some of that. More acceleration than a 818R could probably stick to the ground. They tried upping the scavenge lines size to AN16, that didn't work.

With the previous wet sump pans, they had never experienced this issue. The problem with the wet sumps was they were filling the heads with oil. So for 2017, they switched back to a Killer Bee pan and pickup. But the key was they machined ports in the bottom of each head and ran AN lines to a Tilton electric pump mounted low out the picture above, down by the frame, then lines from the pump back into ports installed in the OEM plastic oil fill pipe. That empties the heads of oil and drops it right back into the KB pan.

Sorry, I didn't get better pics of that setup but I'm sure you can imagine it.

Very cool!

However, for 2018 they are scrapping the Tilton pump system and going with an Aviaid DS setup. Despite his success with the above system he still wants a true dry sump. I told him my experiences with that setup and how to rearrange the pump blades for an easier install. This car not only does Time Attack but up to two hour enduros and they want a DS sytem with a large tank again.


And because this is an FF forum, the Joey Logano Daytona Coupe featured in the Gas Monkeys episode a few weeks ago:

....

And if anybody is thinking about a sequential dog box I talked with every vendor about using one in a 818 and STI. Just be ready to spend $15 to $25K. And another $4K for a Geartronics GCU if you want that <you do!>

[Wayne Presley]

Gator, I'm surprised I didn't see you there. I was there 9-5 Thur and Fri.

[Sgt.Gator]

Gator, I'm surprised I didn't see you there. I was there 9-5 Thur and Fri.

Hi Wayne, sorry I missed seeing you. I was at the show Friday - Saturday. I didn't hit the Ford Performance Booth until late Saturday afternoon. I spent a lot of time in classes this year. Great show, I just wish it wasn't a couple of days after the 25 hour at Thunderhill. I don't think I'm capable of doing both in the same year and I'd rather be helping Retro Racing at the 25 next year.

[Scargo]

What did he think the advantage would be of the Aviaid system over the Dailey? I know they are laid out differently but why does he think it will work better?

[Sgt.Gator]

What did he think the advantage would be of the Aviaid system over the Dailey? I know they are laid out differently but why does he think it will work better?

He mentioned two things. A different pan design that keeps the oil going to the scavenge lines under acceleration. I told him I've used the ARE and Cosworth pans, and just got the Aviaid billet pan. My non-engineer's eye and experience tells me the Aviaid pan is the best. Of course it's dang expensive. Or he may make his own design DS pan.

He also never liked the way the Dailey drives the pump. It runs off the timing belt, which I never noticed before, but you can clearly see in the image below from the Dailey website, and two images I found on NASIOC. One of the timing belt pulleys has an extension that is driving the DS pump belt. I always thought it ran off a mandrel on the crank pulley, but now I see it doesn't. He didn't like adding the stress of the DS pump to the timing belt. He'd rather run a pump off a mandrel on the crank pulley like the Cosworth, or off the crank pulley A/C ring like most of the Subaru systems you find, ARE, Aviaid, Element Tuning.

Subaru-EJ.jpg

..

[Bob_n_Cincy]

He mentioned two things. A different pan design that keeps the oil going to the scavenge lines under acceleration. I told him I've used the ARE and Cosworth pans, and just got the Aviaid billet pan. My non-engineer's eye and experience tells me the Aviaid pan is the best. Of course it's dang expensive. Or he may make his own design DS pan.

I'm running the Aviad system.
On the Aviaid pan the ports are pretty close to the engine mounts. I did some special pipes to rather than hoses.
Bob

ds1.jpg ds2.jpg ds3.jpg ds4.jpg

ds5.jpg ds6.jpg ds7.jpg ds8.jpg

Gator,
Michael and I were at PRI Thursday and Friday. Ran into Wayne and Eric.
We saw Dave but he was busy talking to someone. No surprise there.
Bob

[Scargo]

As to the Can Jam Motorsports STI, it's impressive and one of the few cars I've seen where they pull fresh air into the turbo from outside the engine compartment. Very smart and probably worth some HP.

I still like the Dailey setup. Positive drive that won't slip and the tension on the bolt from the DS pump belt is somewhat offset by the tension from the timing belt. Perhaps a better bolt, wider base, etc. is in order for the pulley/bolt mounting.
I think the timing belt is good for the stresses put on it if you run the good blue racing belt.

I want to do an undermount turbo so my exhaust would be fairly custom anyway unless the KB header can be adapted. Thus I am not feeling challenged by the pulley/snout down there. If oil moving away from the suction ports in the pan is a problem with the Dailey pan, under hard acceleration, I think it can be dealt with through some mods.
I may or may not want a reversed intake on my 818, like on my STi's, but the scavenging pumps up top, competing for space with the alternator and a confluence of hoses up there and the pump heat right next to the intake manifold is not appealing to me.
I re-read almost all of the travails you and Plavin went through with your DS systems. I still want to go that route.
I guess you are still on the 10mm pump you went back to? Everything is OK with the underdrive pulley?
Thanks for the update from PRI.

[Scargo]

That's a great idea! I also like how you tied down the tubes so they can't vibrate too much and fatigue. Good luck!
PS: I did similar with my breather on top of the engine. Where head vents Tee together I made a hard tube for the connection.
balance tube small.jpg

[Sgt.Gator]

Bob and Michael. ya'll do great work!

Scargo, On my STI I'm running a full sized Fluidamper crank pulley and a Cosworth rebuilt OEM oil pump. To make the Aviad pump spin slower I'm using a larger DS pulley. 5.5" I think. I'll be doing the same setup minus the Cosworth oil pump on the 818R soon.

Can Jam had his tank mounted in the rear seat area, you would think it should have fed the Dailey pump fine even going against the force of the acceleration. In an 818 you could mount the DS tank even with or slightly ahead of the Dailey return in fitting and should not have that problem.

[Scargo]

Bob and Michael. ya'll do great work!

... Cosworth rebuilt OEM oil pump. To make the Aviad pump spin slower I'm using a larger DS pulley. 5.5" I think. I'll be doing the same setup minus the Cosworth oil pump on the 818R soon.

Can Jam had his tank mounted in the rear seat area, you would think it should have fed the Dailey pump fine even going against the force of the acceleration. In an 818 you could mount the DS tank even with or slightly ahead of the Dailey return in fitting and should not have that problem.

And it's a 10mm pump? Using its internal pressure relief valve? I know some DS's offer/have an adjustable relief valve on the pump assembly. I think I mentioned that I thoroughly port my pumps. I'd say that there's a significant restriction and potential turbulence area where the oil leaves the pump's gear chamber. At about 8 o'clock in the picture.

I have lots of small burrs I use in that area. I am well equipped as I have Foredom and Dremel tools since I do my own head porting. If you or anyone else is interested I have documented a lot of the oil system mods I do on an EJ 25* on NASIOC where I am Scargod.
Here's a few:
https://forums.nasioc.com/forums/sho...&postcount=139
https://forums.nasioc.com/forums/sho...8#post45456748

[Sgt.Gator]

Scargo nice write ups!

I used an OEM 10mm on th LGT wagon that is in most of the testing in this thread earlier.

On the newer to me STI my short block builder said to use the Cosworth 12mm. It was a highly modified built block.
Melted now due to a cracked burp tank neck....but the oiling system worked great.

http://www.rallispec.com/eng_opu_cossub_t.html

[Scargo]

... If I were to disconnect the AN fitting/hose that returns to the tank, could I keep the separator tank full and allow the engine to pull the oil from the separator tank and the scavenge pump to push the oil through all the hoses and coolers, thereby purging all the old oil and replacing it with new? I haven't been able to find out how fast the oil is pumping because if it is too fast, this would be a really bad idea. It may be a really bad idea anyway, but I think the concept works. This was not one of those things I was just going to "give it a go". Any thoughts, data, or other ideas would be welcome. If this is the dumbest idea you've ever heard, be kind, I am learning. Thanks

Looking at flow rates for a 10mm pump @ 600 RPM I calculate that at 1000 RPM (race car idle speed?) you would pump a quart every 7.5 seconds. That's no more than half the GPM than a home water system is capable of doing! At 1/2" ID it might come out in a pretty good stream though.
You might have one quart in the hoses. I calculated my volumes once for -10 hoses that went to a large oil cooler, filter block and back. Around ten feet of hose, as I recall AIR... Was right at one 1/2 quart for hoses. I figure 1.5 for the whole external system which makes sense for my wet sump system volume of 8.5 quarts with KB pan and Accusump.