Hi Phil

Thanks matey - the diff in exhaust and inlet now makes sense to me now.

Hi Gareth

That graph is very useful indeed . I will have a read of the article right now.

I appreciate you taking the time to try to explain it to me at all

Now you explain it, I do remember boost threshold, so that now makes sense. Clearly this is exactly the opposite of part of what we are trying to achieve.

Lets leave cams to one side for a moment.

HOw much difference does the porting of the head make on its own.

Lets take my engine for example (more so I can take as read what I have already).

Lets say that all other things generally remain equal (ie comp ratio).

Lets say that my engine produces 400bhp on std comp.

So now, I port the head (both inlet and exhaust sides) to improve the flow as much as possible. BUT at this stage, everything else remains the same.

Assume that the map is re-optimised to avoid problems, what will happen overall to the engine?

As I see it, this will effectively improve the air flow through the engine, and as such, 2 Bar from the turbo will be at a greater volume.

Correct?

JJ