Oil Blow By On Drag Strip?

[BADR33]

hey there, i took my skyline to the drags for the first time since i have had the car retuned and a bit more boost in to it.

the engine has never blowen any oil out the breathers even during dyno tuning, drifting etc.

first run at the drag strip and its pissed alot of oil out of the breathers so it went everwhere in the engine bay(i wasnt running a catch can)

but it only does it when i back off at the end of the strip.

rb25det standard long block with bolt ons

engine was running approx 1.2bar, and was making between 310-320kw on the day, im was only revving to 7000rpm as thats what my bee*r limiter was cutting at. had been dyno tuned on 19psi to 325kw with no knock or problems

no oil or mist comes out of the breathers under idle or free reving to redline as what would be expected if the rings were gone.

car still runs fine and holds good oil pressure.

engine wasnt knocking, boost spiking or anything. i own my own dyno tuning shop so i know what was done and how the car was behaving.

so has anybody here had problems with oil getting stuck in the head and then pouring out under decel?

what have you done to stop this with out pulling the head off?

im going to compression test the engine on monday, and hopfully get it back on the dyno soon to check to see if its getting blow by under boost.

if the head has to come off im going to put some restrictors in the block and an external head oil drain down the back.

what size restrictors do you guys use?

i will also be looking at arp headstuds and running a .5mm metal headgasket. so i can run less boost but make the same power. or the same boost and make more power.

will give me a chance to look at the bores and see if it will need the bottom end rebuilt,

[NYTSKY]

Yeh i get oil stuck in the head with hard driving. You will need to have a good catch can system setup or put restrictors in the block or both.