It can be - but with DI Diesels you're more likely to make the situation worse than improve it - the swirl generation is very important to get good quality combustion at all engine speeds. Most of the time when Dave in his shed gets the die grinder out and opens the ports right up, the gas velocity falls flat on it's arse, the flow bench will say it's moving shit loads, but doesn't take into account what actually happens inside the ports.
But currently, the heads will flow enough for 250hp+ without any issues, even if we require pretty high boost pressure to get the air in the cylinders - good turbos will allow that all day long but it doesn't matter, since we cannot provide fuel to burn with that air. All 8v and 16v HDis are fuel limited basically as soon as a decent turbo goes on.
But currently, the heads will flow enough for 250hp+ without any issues, even if we require pretty high boost pressure to get the air in the cylinders - good turbos will allow that all day long but it doesn't matter, since we cannot provide fuel to burn with that air. All 8v and 16v HDis are fuel limited basically as soon as a decent turbo goes on.
