269 | PID Tuning Explained - question about if there is a rule of thumb

In this webinar the example used was on cam control

say you have finally settled on pid settings / base duty settings to get a good response (in the cam example) at a particular temp and your happy with them

its going to be incorrect settings for colder temps / thicker oil etc

would you keep the same duty cycle and modify the pid values to get good control at the lower temp?

or would you keep the same pid values and modify the duty cycle for the lower temp?

or is it a combination of modifying both to work at the lower temp?

is there any sort of rule of thumb - or is it a case of test test and test - and get the pid / duty cycle correct at those temps as they may not have any sort of linear type relationship between things?

yes - this can be solved by lots of testing - but when you have an 80deg thermostat - it only passes through say 50deg for a few mins as the car warms up - then you have to wait for the coolant temp AND oil temps to both drop to ambient again before you can re-test otherwise they might be "out of sync" from a normal warm up and any results you get in this state could be inaccurate compared to values gained from a proper cold start.

or - its "good enough if your getting somewhere in the ballpark as warmup only takes a few mins - get the driver to be careful or limit the output another way"?

Curious more than stressing - but hopefully people who do this regularly may have opinions to offer?

Cheers :)

Ahhh never mind - i've been doing the cam control course today and it seems the recommended method is to just disable the cam control until the system is up to a usable temp - not quite what i'm wanting to achieve - but i guess there are limits to control achieved with an generic aftermarket ecu vs a specific oem ecu designed for that exact engine.

As you rightly point out, the engine spends very little time between ambient cold and and full operating conditions. If the ECU has compensations you can apply, then use them, otherwise don't stress over it.