Datalogging?
 

here is a list of what i can watch. say out of 5 of them whats the best to watch and why?

battery_voltage
coolant_temp
desired_idle_rpm
fp_duty_cycle
idle_spd_valve_d
inj_press_drop
intake_air_temp
load
lt_fuel_trim_b1
" " _b2
maf_counts
maf_voltage
rpm
short_term_trim_
" " "
spark
thrt_pos_absolut
AIN_1
" " 2

I would think it would depend on what you're trying to accomplish.....ie: if you're tuning idle, part throttle, under load, etc. etc.

I log 5 on mine.
boost
rpm's
MAF volt
egt
tps

if you can do the injector pulse that will help a lot!

MAF volt
tps

are u comparing them togather?

The tps showed how bad I was at lifting the petal. I wanted to add timing as I went more on the throttle so I would have more control of the power going down. Turbo's are hard to control sometimes.
THinking out loud again. But it was a good information on how everything worked. I am still learning.

+1..
Unless you have done a major change to the car, you don't need to much tuning that is data logging related.

When dealing with a new blower setup or a MAF change, then you would want to datalog MAF voltage, TPS, Load, RPM, and timing

these 2 say invalid while data logging

maf_counts
maf_voltage