xpc66

I decided to start some prep work on the E7TE heads I bought and noticed some wierd things.

Intake valve opening area standard = 1328mm2
Intake port area = 1400mm2

Exhaust valve opening area standard = 1114mm2
Exhaust port area = 800mm2

Now is it just me or does that exhaust port look like it has authority over the exhaust valve?

I know there are lots of flow bench figures out there, but I don't believe in flowing heads for optimal performance as it only deals with pressure drop and does not take into account turbulance, rarefaction, resulting reversion, etc. But I don't see the point in having a valve that opens more than the duct (exhaust port) it's serving.

I'm dropping in a better cam with 0.4409 net valve lift and the figures are going to even more skewed:


Intake valve openiing area new lift = 1589mm2
Exhaust valve opening area new lift = 1292mm2.

Comments please?

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EDXR8

Only thing I can come up with is that the valve creates turbulence therefore it needs to have more open area to flow the same amount as the port. The exhaust port flows so little on those heads, maybe every bit counts. The E7 heads are a really bad design anyway so I am not sure if there is any real answer.

blue66coupe

with more than .5" valve lift is wasted with stock ports, but the valve open duration past the max flow point increases so it's ok as long as not too much cam/engine speed for the wheezy ports in the first place, as your 'breathing' range is already way past the range of the WHEEZY (stock) heads