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Talk about engine building here. New products, tricky questions or showcase your work - If it's engine building related it's welcome here.
I am looking to install a dry sump oiling system in my boxster so i can use it on track without the oil starvation issues these engines has.
Unfortunately there isnt a bolt on system for that engine atm in the market so i have to make a custom.
I have some thoughts but i need some opinions from more experienced people on dry sumps.
-First of all lets focus on how the oil will go in to the drysump oil tank.
1.Keep the stock oil pump (gear style /photo attached) to pick the oil from the stock oil pan and send it to the drysump tank. I know that in that way the stock pump and pick up will starve as the oem system when i have high g forces, but the stored oil in dry sump the tank will keep feeding the dry sump pump and my engine will have constant and high pressure oil? How much time the dry sump tank can supply oil to the engine without the refilling from the stock oil pan? (my engine oil capacity is 10litres so i assume thats the capacity of the drysump tank i should use.
2.Will the stock pump be damaged from the oil starvation? i assume not because there will be always some small amount of oil to lubricate the gears.
3.Can i remove the gears from the stock pump and use the scavange stage from the dry sump pump to scavenge oil from the oil pan through the stock oil pick up-stock oil gallery? Thinking to connect the scavenge line to the oil filter (oil filter will be removed and relocated to pressure in line) the length of that route will be 1-1.5 meter will that affect the scavenge effect?
4.Do both of the above 1-3?? maybe there is an advantage i cant think.
-Another question i have placed a low mount ball bearing turbo can i use a scavenge stage to scavenge oil from the turbo return?? (there is a small tank just bellow the turbo oil drain with a breather)
-Question number 3 the engine is a boxer 6 cylinder that has one scavenge pump on each head to return the oil to the stock oil pan. They are not well designed and for low cost i assume there are only 1 in each head on opposed position. On the right head the scavenge pump is in the rear section and on the left in the front. There are some senarios like hard braking accelarating while turning that the oil stays in the heads. should i use dry sump scavenge stages to scavenge oil in the other side the the stock pumps? Can i use a Y fitting to connect the lines to 1 scavenge input assuming the oil wont be in both areas at the some time (cant brake and turn left and accelarate and turn right in the same time)
-Is there a rule of the drysump tank capacity?? my stock sump capacity is 9-9.5 litres
I would like to have your thoughts and ideas really appreciate it..
I'm not sure you'll find many folks that can answer your questions. But here is my input:
Eventually you may be able to use the same size dry sump tank as the current oil capacity, but for initial testing, you would not want this to be too small, so you should plan on using probably 50% more capacity.
I think this is a very difficult project unless you have a few engines to experiment with.
Without knowing the details of that engine, here is the approach I would take.
I would consider using the stock oil pump to provide pressure. It's already sized right, and plumbed to the galleries, has pressure relief, etc.. I would figure out how to feed it from the dry sump tank, by modifying it's intake/scavenge side. The problem with using it as a scavenge pump, is it may not be efficient without a pressure head to pump against.
I would build a new dry sump pan (unless it was easier to modify the stock pan/sump with multiple scavenge pick up points , and using an external 3 or 4 stage pump feed this to the dry sump tank.
I have seen the stock pickups used in dry sumps by having a feed machined into the sump plate that aligns with the OEM pick up port in the block, and is usually sealed to the face with an O ring. This then runs to the outside of the plate where the feed from the tank is plumbed in.
There have been hybrid systems similar to that used successfully on many engines - scavenge pumps (some electrical) feeding the reservoir with the OEM internal pump being fed from the tank.
It seem there are some folks building Boxster dry sumps - have you seen this, for example? https://rennlist.com/forums/racing-and-drivers-education-forum/981880-boxster-dry-sump-system.html
Have you seen this Porsche oil system test rig? - https://www.youtube.com/watch?v=fv53RbvgfGc
The V8 version - https://www.youtube.com/watch?v=Ny9xl7iWayU
I have seen these posts... Actually the guy in the forum is done something similar with that i write in the first post. He is not saying any details about it...
My thought is to feed the external dry sump tank with the oem pump not to feed the oem pump with oil from the extra tank... The engine will be feed with an actuall drysump pump...
Ah, I'm not sure the internal oil pump will have the capacity to ensure it is scavenging more than the pressure pumps are drawing - in fact, I'd put money (a small amount) on it not being able to do so.
If you're still going to be using an external pressure pump, not sure why you wouldn't add a wafer for the pressure side - either way you're looking at modifying the OEM oiling and sump.