Aside from 4.8v drawing down the battery faster.....using a 1.8 ohm coil should be fine!!
If you don't mind the "top-heaviness" of the setup...VAPE AWAY!!

I've used my IGO-L on an eGo 650 Twist....1.8-2.0 ohms.....4.0v -- Not bad!!

Although I do prefer my MVP v2 when I drip.....longer battery life....and more stable, physically.....
Happy (vaping) Trails!