Definition of "lag" and "spool up"

[newsh]

Personally I do not feel the term spool up to concern turbo only, but the whole setup.

That makes sense. And an important difference to all the other posts I think.

I also like the "acceleration starts to accelerate" idea.

[Bram]

That makes sense. And an important difference to all the other posts I think.

I also like the "acceleration starts to accelerate" idea.

Now I have read a few more posts in this thread I think that for me I make a difference between engine- and turbo lag and spool-up:

Engine Spool-up = the acceleration start to accelerate describes it well. It's the moment at which the feeling of the 'seat starting to push in your back'. So I think it is not related to time, but more to RPM, throttle position and gears your are in.

Turbo Spool-up = turbo pressure build-up, but that most of the time does not relate to a higher engine output at the same time.
In my experience spool-up in the higher gears happens earlier then let's say 1st and 2nd gears, although it is giving a different reaction on the engine spool-up characteristics.

Lag = the time before that the spool-up takes place after you have floored the pedal different for turbo and engine, as described above.

[Jamo]

FFS this is a good thread looking at a definitions of common terminilogy not have a go at a tuner thread.

Read the 1st post

how You personally define lag and spool up.