just recently got my sonoma running...

quick summary, its a lq4, tc78, 4l80e.
speed density tune, 2 bar map, have ran 15 psi

tune is 11.2 wot a/f and around 12-14* timing at wot.

its smoking on decel and im not sure if too much oil pressure is forcing past the bearings in the turbo or if i building too much crank case pressure... i am guessing crank case becasue i dont have an evac setup of any kind on it yet.

this vid is 1/2-3/4 throttle around 10psi
http://www.youtube.com/watch?v=xYGnI...eature=related

 

its got a -10 drain at a really good angle to just below the pan rail, shouldnt be an issue with oil drain...

let me know if theres any other questions

thanks

 

what is your crankcase evap setup currently?

 

just running stock pcv hoses from intake to valve covers... no actual breather.

is it gonna be enough to put a breather on my oil fill cap, or am i gonna have to put a catch can with hoses from each valve cover. and i hope i didnt hurt anything by driving it like this... it was running great when i parked it.

 

Most guys on here running open crank case system or closed factory style going back to the intake?

 

Local guy had the exact same problem this past weekend at the ls-fest.


You need to let that thing vent to atmosphere. His was so bad it pushed the valve cover gaskets off his valvecovers, haha.


We remedie'd his with a pit-style fix. Put a small breather on the back driver hole and put two rubber hoses on the passenger side venting to empty bud-light cans.


It was a good temporary fix, but ultimately he needs to vent the passenger side to a large breather through his oil fill cap.


For what it's worth, before we went to a vac pump setup on mine, we tapped the valley cover and put a -12 line to a home-made catch can with a large breather on it. Just be careful where you tap it or you'll get too much oil from the lifter vally.

 

okay thats what i thought. thank you very much for the quick response. ill be trying this in the next few days.

thanks again