kikiturbo

I will put up the thread when I have the sump welded... I was just figuring out where to place the tank..
Yeah, I am making the dry sump "on the cheap"..

LetsGetThisDone

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Dry sump pumps usually spin about 1/2 engine speed. Just FYI.

Bee-Raddd

that pulley looks waaaaay off in size. what are u running the pulley from? picking up off the crank? the pulley on my drysump is barely any bigger than the body of the pump itself.

Its about flow and pressure not rpm.

kikiturbo

yes, that is because first dry sump pumps used georotor gears and those dont work above 4000 rpm. I am using a 2 stage gear pump (just like the one in the OE oil pump) and my Titan pump is rated to 7500 RPM continuous use. However, I strongly suspect that is the specification for the pressure stage and not my scavenge stage which should work at even more RPM if I wanted to run it. Stock mitsubishi oil pump runs at 2x engine speed.. If I was in the US I would probalby run a 2 stage scavenge from Dailey engineering and that is rated to almost 10 000 RPM IIRC...

kikiturbo

I am running it off the aux belt and not separate toothed belt like you do.. I presume you run the pump at 1/2 engine speed.. I am not worried about pressure as I am running only scavenge stages, pressure will be handled by the OE pump..

Dallas J

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Ive never really looked into it, but why doesn't anyone run a scavenge pump from the stock or a modified pan to fill a reservoir that then feeds the stock pump (gravity fed maybe?). Is there a major disadvantage there or something inherant in a drysump that I dont understand?

Construct

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Isn't this what kikiturbo described above? He's using the OEM oil pump as the pressure stage. The external pump stages are for scavenging the oil pan.

OEM oil pan shape isn't ideal for a dry sump system, unless you modified it to make it significantly flatter. You'd want scavenge pickups at least on both sides of the pan, with minimal area in the pan for oil to pool. Something like the old MAP dry sump pan: https://www.maperformance.com/blogs/...-now-available

LetsGetThisDone

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Gerotor gears most definitely work above 4k rpm LOL. The GM LS engine have a gerotor pump that is directly crankshaft driven, as in the inner gear is mounted on the crank shaft. Walbro fuel pumps use a gerotor gear set, there is no way those are under 4k rpm.

The OEM oil pump does not spin at 2x engine speed, its quite a bit slower than that. The balance shaft is 2x engine speed, but it is driven off of the small driven gear of the factory oil pump, so it is geared up to spin faster. The factory crank spricket is 24 tooth, the oil pump sprocket is 18 tooth. That spins the pump ~1.33x engine speed..

Ayoustin

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Construct

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I'm curious about the hybrid setup. When you're spending $5-6K minimum on a dry-sump kit, it makes sense to spend a bit extra for a complete system. On the other hand, I'm all for keeping things simple and keeping weight down.

What's the actual disadvantage to using the built-in OEM pump as the pressure stage? If you're running at reasonable RPMs, why not re-use the OEM pump as the pressure stage? Does an external pump have any real-world advantage?

kikiturbo

I went trough quite a lot of pump specifications and contacted a lot of pump manufacturers. Spoke to a US georotor manufacturer some years ago too about a custom pump... wanted to make internal transfer pump...
Basically, looking at georotor dry sump pumps that are available on the market, those are limited to about 4000 rpm. That is a shame as those are quite a bit cheaper than what I have.. On the other hand those are not good for scavenging.
Gear pumps and vane pump or twisted rotor pumps (Titan, Daily, petersen, Verdi) are officially limited to 8000 RPM or above.
Ok, OEM oil pump runs at 1.33x engine speed on the input shaft and 2x engine speed on the output.. still way above most dry sump pump.

kikiturbo

there are advantages and disadvantages in using OEM pressure stage...
Main disadvantage is that you cant tune the engine to pump speed ratio to have the pump run in its most efficient region and not just run too much oil trough it. If you run above the usual engine RPM, say in a race engine that runs 8 or 9 K all the time, then it is beneficial to slow down the pump.

There have been hybrid setups before. HKS dry sump is one such system. It has the scavenge stages under the sump and is run off the crank nose with a tooth belt. benefit of this is that it keeps the AC and still maintains oiling at high lateral G.
I run the hybrid setup for a couple of reasons.
I dont like running the tooth belt off the crank nose. My car sees snow, some gravel, and I am worried about that belt drive. So my intention was to run the pump some other way. There were 2 ways...
1. First was using the balance belt drive.. which is a nice idea but still requires quite a large sprocket (as you cant fit a small drive sprocket there because of the size of main seal) and putting a pump in a safe place would require a custom front cover with a custom main oil pump. That was determined to be too expensive.
2. So I decided to run the pump from the aux belt. In order to place the pump there and not hit the exhaust elbow I cant run a long pump. This means that there is no space for a normal 3 stage pump but only for a 2 stage pump which is scavenge only.

Running the OE oil pump means that I dont have to worry too much about pressure pump speed and I can concentrate on getting the scavenge stages to run at such a speed to maintain some vacuum in the engine. Yes I plan to run a sealed engine under some vacuum. No Cam cover breathers if possible. This will be checked with a engine pressure/vacuum gauge.
3. I am on a budget.. cant afford a Norris system and find this interesting project.

Basically...
- cut stock oil pan, with pickups on left and right side. Height at the point where the exhaust passes under will be even higher than Oe to provide more clearance for the exhaust.
- internal tube from one side of the sump to the other. I dont like seeing all those scavenge tubing going around the engine
- Siamesed outlet from the two scavenge pumps into one 16 AN outlet line to the oil tank.
- oil tank to be placed in the space occupied by the ABS unit and going all the way down. Tank serves dual purpose of air oil separator and catch tank. Total capacity about 10 litres, oil capaciity about 6. 12AN air outlet line on the top to engine intake before turbo. 12 AN oil outlet on the bottom. Tall narrow tank.
- 190 mm pulley for about 20% underdrive from main sprocket. Final ratio to be determined after we see the vacuum in the engine we get.
- Titan TG2 gear pump, 2 stage scavenge, 30 mm gears. This unit in 3 stage form is usually run on evo engines at about 50% engine speed.

Ayoustin

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kikiturbo

I started by making a baffled wet sump with electic transfer pump that would activate in right hand corners.. But once you get an electric pump with enough flow you end up with a heavy system. There was a transfer wet sump that was made in the UK that used an external single stage mechanical pump, but at that point you might as well just to a dry sump.
I am not a fan of dry sump complexity but I recently removed the AC and said "what the hell lets try it".... I agree on your stated disadvantages of hybrid solution but I will not run above 8300 rpm or so, so am not too worried about cavitation. Oil feed is not so much of an issue but correct belt drive is. You cant drive the pressure pump from acc belt.. but scavenge pump is not so much of an problem as if it slips from time to time it is not a problem.
Actually the main reason I want to try it is the possibility of running the engine with partial vacuum in the sump. My whole car is a big experiment.. it will become apparent soon enough..

Ayoustin

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