I agree with Greg about you use what is needed for a particular application
When dialing in your inj slopes, offsets and the like ............
You need enough Closed Loop data for various driving conditions to allow
EA to be fairly accurate with its recommendations.
sooooo
A long dlog would apply in that situation
I've used 30 sec dlogs many times in the past to pinpoint specific conditions.
Here is a quick example for you
I had a nasty lean spike when going from a steady low load cruise condition to
a max power WOT condition.
I'd get the car up to about 20 to 25mph in 3rd gear
tap the space bar to start the capture for about 2 to 3 seconds
go to the floor for about 2 to 3 seconds
tap the space bar to stop the capture
Much easier to analyze 15 to 30 seconds of data
rather than go through
megs and megs of data you'll have with a long dlog
Grady