hey guys, how does the TVIS works?
from my understanding, the butterflies are open at idle then (rpm??tps??load??) triggers and energises the valve to open for vaccum then closes the butterflies. then at x rpm it deenergises the valve to close cut vaccum and opens the butterflies again.
 
if so then disconnecting the tvis electrical connector should keep the butterflies open at all times?? i will delete it in the future but i just wanna see the difference with it connected/disconnected for now. cheers

if you disconnect the tvis the butterflies will be open all the time yes, so you loose a slight bottom end.
if you go aftermarket ecu it gets disabled regardless, then its up to you to re-enable it via an RPM switch.

if the EMS was piggy backed would it still be disabled? so what triggers it when using stock ecu?

I thought it opens at about 4200 revs.. so perhaps that's the trigger for the ECU?

yeah i agree, i was wondering tho what triggers it to close the butterflies from being open at idle tps? load maybe?

Basic description:
http://en.wikipedia.org/wiki/T-VIS
What happens if you disable it:
http://websworld.org/marcel/tech/tvis/tvis.html

thanks for the links mate! very helpfull