both, kind of... range is 25-70ms in 0.5ms steps
regardless the way to optimise dwell is the same no matter what your set up.
set your desired input pressure - here is where you need to be concerned about your upgrades. lighter bolts, qevs and larger volume rear cans allow you to drop your operating pressure, while the epiphany upgrade increases it. your OP can vary from 110psi to 260psi depending on internals.
then drop your ROFD to 0.
open grips, press programming button until the LED is solid red.
then pull and hold the trigger for 3 seconds; the speaker will chirp 5 times to indicate
that you can make adjustments.
hold the trigger in, press the programming button to adjust down until it bottoms out (chirps and flashes) - it will give low pitched chirp for each adjustment down.
Then release the trigger.
next set your dwell - you will need air to do this properly.....
use program button to get to solid yellow LED.
use the above method to bottom out the dwell.
bring the dwell up in 5 chirp stages - trying to fire the marker after each stage. once you get a full blown cycle, add 5 more chirps, or at this time of year 10.
if you find you are lacking consistancy over the chrono, bring the dwell up some more until you get a nice steady FPS - you should be able to get shots to within +/-5fps.
you can find all the information on dwell tuning in the ion manual, and the blackheart settings are summarised in a table in the manual for it.
if you are missing manuals you can get downloads via smart parts website or from us here:
http://www.scottishwarriors.co.uk/index.php?action=tpmod;dl=cat3