Sudden burst of white smoke?
 

N00b here, turbocharged the car, set up a conservative base map based on brain's timing and fuel. Planning to switch clutch and flywheel this week before doing hte 500mi break in and then take it to a dyno.

After installing turbo, drove around a lot while running autotune, then did a couple of hard pulls. Have mspnp set at 195kpa fuel cut. after about 10 pulls, got a big cloud of white smoke. drove home nursing the car, no smoke thereafter. I have a revlimiter coolant reroute and thought that maybe despite this that the car overheated and built up high coolant pressure and some escaped out the edge of a hose. Also suspected headgasket but the white smoke is not continuous.


Today, decided to start it back up to try to diagnose the issue and see if I had any white smoke upon idle. None. Drove about 20 minutes to lunch, taking it easy, ate for about a hour, started driving home and stopped at stop sign. When accelerating lightly from idle, got a sudden, singular burst of white smoke. Drove home thereafter, no more white smoke...

What could be happening?

I am thinking either:

1. fan maybe not kicking on, coolant too hot, pressure too high, a small amount burst out of piping, depressurized hte system, and instantly evaporated. (Tunerstudio shows max temp around 200)

2. Blown headgasket? Would it leak briefly like this?

Tune file attached... any chance it is too aggressive anywhere?

hard pulls pre-dyno bad idea.. .yes... but smile on face also yes...

Is it smoking during the pull, or smoking when you let off the gas?

I think the first time was at about 80% throttle. only 50% certain. was around 5-6k rpm

Second time was at about 15% throttle, was around 3-4k rpm. 100% certain. let off and let it coast a bit and then it stopped smoking.

Thirdgen, what would you suspect if the case was either condition?

Unedited testing/findings:

I checked the coolant level last night and it was full - both within the rad and in the overflow. I let the car idle up to 180 with the rad cap open to check for air bubbles and saw light bubbling if I blip the throttle - not sure if cylinder CO2 or cavitation but not enough volume to make me think it is from the cylinders.

This is not dissimilar to the burp process I took. In otehr words, never burped with nose in air.

Flow does seem to increase after thermostat opens ~180.

Tightened rad cap.

No indication of trufflebutter oil.

Didnt get a chance to do a compression test... actually not very sure how to do one with MSPNP - simply unplug CAS? <- assume doing this will make MSPNP not trigger either fuel or spark and thus not damage coils.

No indication of white smoke yesterday - idled up to 180, drove around for about 20min in 50 degree ambient.

Noticed that rad fan did not turn on even if set to trigger at 100F - likely on the wrong output.

Maybe paranoid but hearing waht seems like a light thunk rhytmic thump coming out from the old water-neck area. Could not tell if at valve-level, Has cylinder-level or lower. Spun bearing? Valve? Paranoia?

Car now at shop for clutch ACTHD, Flywheel, and 3.9Torsen. Need 500mi. break in before true tune... hope I didn't fuck things up with pre-tune joyride.

On another note, exhaust manifold obviously not sealing well to head - seeing oil/carbon deposits around cylinder 2/3 and hear exhaust leakage. May need resurface or gasket. Not sure if this may have some association with coolant issue - warpage for example?