Inlet manifold

[DR_EVIL]

Once lapped take them to get a 30 degree back cut next time, its cheap and makes a little more flow at smaller valve openings

[lanceb7]

I get that done next time I do a head, does same help with a 16v?

[DR_EVIL]

Yes. Here is a picture of the valve deshrouding, you can see the curve created around the valve.




Here is the effect.

Blue line is the bare ported head.
Red line is after Deshrouding the valves.
Adding a 30 back cut on the valve and a 70 degree on the valve seat gives the yellow line! Massive improvement for a small amount of work.

[lanceb7]

Ah yes I see, I do that next time does it not effect your compression ratio?

[lanceb7]

Wow that is a massive difference for just little work! Very impressed with your work an your own flow bench getting these results 👍

[DR_EVIL]

Ah yes I see, I do that next time does it not effect your compression ratio?

Yes, best remeasuring combustion chamber volume afterwards, I wanted to drop compression a little anyway

[lanceb7]

Quality that's top work, I will remember this