Calc pid to display previous frame value (delay data)

[Gelf VXR]

As title, is it possible to create a calc pid to display previous frame value, I'm sure ive seen this somewhere?

For example, delay the MAF 1/10th of a second as it seems to respond quicker than the MAFSD

[joecar]

Yes... in the V7 user manual pdf, look at the calc pids section, in the functions table look at the function FRAME.

~Moderator~

[Gelf VXR]

Hi Joe

I think this is the one I want, I want to return the value of an earlier or later frame, not the frame number, do you have an example of this pid?

value() Syntax: value({PID},frame) Arguments: {PID}: a PID name. frame (optional): an expression. Return value: The specified PID’s value for the specified frame. If the frame number is not specified the current frame number is used. If the frame number is less than 0 then frame 0 is used. If the frame number is greater than the last frame, then the last frame is used.

[statesman]

You can't 'shift' the actual MAF readings. You create a PID which becomes a new parameter and you then do the shift in that calculated parameter... the original MAF readings remain intact.

I don't see any value in shifting the MAF readings... they are what they are and that's what the PCM is seeing and using to do its fueling calculations.

I have done a shift for wideband readings in the past (I now use spreadsheets for all my tuning so I no longer use this scanner function). I'll put up a couple of pics to show you how I shifted the wideband readings and you can use that as an example of how to do a frame shift.

20737

20738

This calc.PID was set to a 5 frame offset for the wideband as the vehicle I was tuning at the time had gutted cats and the WB sensor mounted in the rear O2 sensor bung... huge delay in wideband readings. I also divided by lambda to auto-correct for PE fueling situations (optional way of doing things, but worked for me).

[Gelf VXR]

That's what I'm looking for, I think we are on the same page, I always see MAFSD lag just behind MAF, as you note the WB has a further delay in reading, I want to experiment with delay to the MAF and MAFSD a few frames to apply the fuelling correction.