Tuning Cam Control with cold oil

Hi all.

I'm working my way through a few courses while I am away with work and preparing for what I'll next be doing on the car.

For context:

Engine = McLaren M838T (3.8 V8 Twin Turbo with 4x variable cams)

ECU = Haltech Nexus R5

I've got the engine idling reasonably well, and it revs without load, but a recent session on a dyno demonstrated a problem I am facing. I am yet to configure the cam control and had hoped to get a rudimentary tune on the engine before introducing the variable timing. I left the cam solenoids as 0 target (0% duty)

However, while the McLaren does indeed idle with the solenoids at (near) 0% duty - this rest position on the phasers is actually -15 degrees intake and +15 degrees exhaust. At anything above 750rpm, the cams are immediately pulled into a more normal position.

When I try to put the engine under load, my cams are remaining in this -15/+15 state and preventing me being able to tune it. So I need to get the cam control working before I can start tuning. I actually have the full cam target maps extracted from an OEM McLaren ECU so I have something to work with.

This brings me to my question. In the course, there's suggestion of leaving cam control disabled until oil temperatures are reasonable - to avoid issues with PID values being wrong due to viscosity. In my application this wouldn't work - since the car won't drive until cam control is enabled and it won't always be feasible to sit and idle to wait for oil temperature.

How would you tune PID for cold oil though - given that the oil will immediately begin warming and thus transitioning in viscosity?

Should I get it dialled in for hot oil and then just guestimate some values for cold and hope it's good (or make an adjustment once each morning)? I can use oil temperature as an axis on the cam PID tables.

I could also create a VE correction table with "Cam position error to target" as an axis - is that worthwhile? I suppose cam position error would only serve to reduce my VE so I may find myself in a rich, and safe, condition until oil temps are up and cam PIDs are working correctly so perhaps not worth a correction map?

Thanks in advance (pun inteded),

Joel

I usually don't find significant issue with cam control and cold oil unless you're seeing extreme fluctuations in oil temp (possibly regions seeing 0 to -20 deg C ambient temp for example). The approach I'd take is to start by getting everything dialled in at normal oil temp and tuned. Then you can test the PID control at cold oil temp and see how good/bad the control is. If you're seeing significant issues then I'd readdress the PID gains during cold start. this may take a few attemnpts since the oil will naturally warm up while you're tuning. Then you can extrapolate the gains between your cold and warm points.