Unbalanced head ports = diving torque curve??

[imported_gearhead]

@Domination

might be an optical illusion but it looks as though you gasket matched and didn’t blend it far enough down the runners. Taper is good for premoting velocity but a bulbus ramp can creat an anyurism in the flow path.

I dont know how far you should go. The intake ports are so gigantic, its smoothed to the bottle neck. What do you mena by “bulbus ramp”. The material you’d take out to open the venturi part of that head aka bottle neck doesn’t appear to be there

@danl

The size of the ports has everything to do with inertia and trying to maximize volumetric efficiency by maximizing the forces of inertia. What you want to do is inertia match the ports. A cold air has more mass per volume (PV=nRT). Therefore it can move at a slower speed and provide a certain amount of inertia (bowling ball at 1mph). The exhaust gas is much warmer and has much less mass per volume. Therefore it has to move much faster to achieve the same inertia (golf ball at 10mph). This is a major limitation of flow benches. Since the flow is steady state you have no way to account for inertia.

Then you have to worry about the air moving so fast that it becomes turbulent and does not move well. You also have to manipulate surface textures to try to keep air from going turbulent.

I understand what your saying here… Now, what would be a good way to figure out if the runners are effecting the loss of torque at all?

What about measuring pressure in the exhaust manifold? then before and after the turbo?

I still think that the head as something to do with it… maybe cam profile, but that cam test didn’t do anything for me. Whenever you look at other heads, they appear to be more similar in size. The ONLY other head I can think of that has big intakes and little exhausts are off of 5.0 mustang motors. All my chevy’s, hondas, etc arn’t as differenciated.