Getting my fmic done in a fortnight considering getting a bov but a turbosmart plumback cos VTA is
too ricetastic. Does anyone know best size? Eg 32mm or 38mm
the 38mm or 32mm is the size of the outlet pipe that gets returned back into your intake. it all depends what size hose/pipe you want to run from your BOV back to intake. Personally i have a 38mm, as i run a 1.5" chopped up radiator hose back into the intake
I'd say get the smallest practical size. Firstly because 1.5/1.8/2L is generally a small engine/turbo/flowing setup and secondly you want to keep the boost as close to the surge line of the turbocharger as possible (ie chosing a lower flowing bov) to maximize turbo response. Don't want to start the whole bov vs no bov debate, but imo you should be asking should i get 32mm or none at all.