A catch can after a hard 20 min run sounds like a bit much. Have you tried a leak down or comp. test. I had a boosted IS300 with the same problem it turned out to be a blown ringlanding.

 

Ditto. Like I said above. . That much blow by has gotta be piston rings.

 

subscribing as i have this issue on track, with no catch can on stock ECU. good luck

 

i plan on doing a compression check as soon as the new spark plugs arrive. I figured I would get two birds with one stone.

I have a hard time thinking the piston or rings are bad as the car feels fine on the stock ecu.

 

what volume will your catch can hold? I run a 1 pint can, and on some tracks I have to empty it after every session. I've never filled it up in one session, but it has enough in it that if I don't empty it, I fill it up during the next session and start blowing smoke.