oil pressure drops at fast acceleration

[quattro-nick]

hi guys
i have a rebuild AAN engine and my oil pressure drops from 5 bar to 2 bar at fast acceleration.on normal acceleration is everything fine
the engine has everything new;oilpump,bearings,rods,pistons,...........
my oil pressure on idle is 1.8-2 bar and on 3000rpm 5 bar; so thats good.(measured with a oil pressure gauge elek and mechanical)
i made some baffles in the sump with no result
afterwards i take the baffles back out en change my suction tube a little bit,also with no results
I know I can place an accusump but normally this problem may not be present so
does anyone have any sugesstions?
my crankcase ventilation is still origional,can this maybe my problem? i have already ordered a oilcatch can

[Error404]

How much power and how may revs on the engine build? Some surge is quite normal but that sounds like a big drop!

[quattro-nick]

i have a rs2 turbo for now and 1.6bar boost redline so i think about 350hp?
inside i have wossner pistons(cr 8:1) and arlows rods good for 800hp and sputter bearings from glyco
but soon I'm going to bild a gt3076r(for 500hp) on the engine so much faster acceleration and I'm afraid the oil pressure also lower drops
how low would be my oil pressure drops if I place an accusump?
It is a really weird problem.

[Error404]

What sump did you use? early AAN without "wing" on the side? Sounds like maybe not enough oil capacity

[quattro-nick]

Perhaps the problem can be also:
-crankcase ventilation?
-oil stays to long in the head,slow return back to sump?
-oil cooler pipes too thin?hole oil cooler pipe on filter housing is about 11 mm but I have two pipes with a hole of 9 mm

[quattro-nick]

i have a 7a sump with the normal 5 l engine oil capacity

[quattro-nick]

Yet for those interested, my engine oil is motul 300w 5w40

[driftin jo]

I would say you have crank case pressure issues caused by clogged breather system, on hard acceleration the blow by is pushing the oil up the drain back path from the head, either that or you are getting boost into the crank case, also caused by malfunctioning breather system.

I have the same set up,tuned RS2 spec, 360hp and have no such problems what so ever.

[quattro-nick]

i understand you driftin jo
but when i rebuild the engine,i also cleaned the crankcase ventilation inside the engine and the tubes outside and normaly when the ventilation is to much i have leaking seals so .......
maybe i can try an extra ventilation to my oil filler cap for the time being and look at the results

[driftin jo]

i understand you driftin jo
but when i rebuild the engine,i also cleaned the crankcase ventilation inside the engine and the tubes outside and normaly when the ventilation is to much i have leaking seals so .......
maybe i can try an extra ventilation to my oil filler cap for the time being and look at the results

OK, but if the one way valve is shot you are boosting the crank case.

[newsh]

Yes, check your one way valve is ok and also make sure the breather pipes at the back below the IM are connected correctly. Thats the other way to get boost to the crankcase, usually results in poor idling too though.

[quattro-nick]

okay,i will check it on monday
thanks

[macspring]

One small comment, ensure the one way valve is the oem one, and not a metal after market one from the US.

[quattro-nick]

so i check the one way valve and it's ok
all the ventilationtubes are open
so i did a test with the ventilation: i removed the one way valve and closed the nipple on the throttle body.
on the other side, I have extended the tube with a bowel to a plastic bottle (see photo)
I have done a test drive and my oil pressure still drops at fast acceleration so the problem is not in the crankcase ventilation or there will be no boost pressure in it
There was no oil in the bottle
maybe a oilflush with a product will help like forte' ?

http://www.forte-nwe.com/EN/Forte-Products/Car/Engine/Motor-Flush.html

[driftin jo]

Wait, your running 1.6 bar to red line, with an RS2 turbo ?? there is no way that's a safe tune if that’s true. Should be 1.85 – 1.9 peak, tapering off to ~1.3 at red line.