It was a bit warmer here today so i tried using the PLX kiwi to get some data, can someone explain in numpty terms what timing advance is and what numbers are good and bad, i assume that + is good and - is bad , it seems to go down with more throttle but Not always the case .
also i have a Gotham tune and i thought i had 100% throttle but i only seem to get 80% max on the readings , is this right?
The throttle reading is never 100% on any tune, I know not why, just the way it is…
As for timing advance is good retard is bad 
what affects the timing , throttle and IATs ?
Throttle position readings all depend on the device taking the measurments. The TPS reading is never at 0 or will it reach 100 due to the fact that it will never be used as a throttle stop…
Certain software will give a tuning reading of zero TP when the maping begins at idle and goes up from there to a setting of 100…
Everything has an effect on the timing maps… you can see 4btdc at idle to as much as 45btdc on coast down…
So roughly how many hp is lost per -1% timing retard on a 260hp Exige ?
I know of no calculation for timing vs HP since so many factors effect the ± of engine timing…Too much or too little will have an effect…Load/temp/water temp/RPM/boost all dictate the timing settings…
The tuner writing the maps can move it where ever he likes…just hope he puts it in the right place…