try driving the Z at lower gears longer that would warm up the oil faster...I drive mostly freeway early mornings at 5th gear only for 5 to 7mins around rpm's lower than 4K at a speed of 75 -79miles. 190F is reached faster... then gun it like a mad man....
City driving would play mostly 2nd and 3rd gear rpms running at 3K+ longer that should do it faster.