Dual pattern cams...Black Magic or Legit?

[eschaider]

Actually, it has everything to do with eliminating the flow imbalances, Buddy.

If you read the first page of this thread, the OP is curious about using different cam profiles by cylinder to correct for the different (mass) airflow characteristics of the cylinders, which were fed with short vs long runners.

The OP was curious if it was possible for the cylinders with the lower (mass) air flows to improve their processed (mass) airflow by compensating with different cam profiles for those affected cylinders, leaving the intake runner differences untouched.

If you accept the premise that individual (mass) air flows for cylinders of the same volume, vary in relation to intake runner size and volume, then obviously, making all intake runners the same shape and length eliminates the variable and the differentiation.

You should re-read the OP's original question. It will help you better understand the responses in the thread.

[Buddy Rawls]

Originally Posted by eschaider

Actually, it has everything to do with eliminating the flow imbalances, Buddy.

optimizing A/F has nothing to do flow parameter imbalances. optimizing A/F cylinder to cylinder is a compensation for those flow imbalances. You cannot improve flow of a motor by A/F compensation. it doesnt work that way. You are simply tuning the motor cylinder to cylinder, compensating for those for those differences cylinder to cylinder.

Ok, I see your issue. You wrote "If you accept the premise that individual (mass) air flows for cylinders of the same volume, vary in relation to intake runner size and volume, then obviously, making all intake runners the same shape and length eliminates the variable and the differentiation."

yes, that fixes the situation of needing different lobes by cylinder. But that is not the question. The question was, if differing lobes for the cylinders for a single plane intake manifold design a snake oil concept? The differing lobes on one cylinder to the next is used to compensate for flow parameter differences. When the question is about the reasoning for a multi pattern cam within its design parameter, ie the typical single plane manifold, your answer is, if it had an IR manifold it wouldn’t need such a cam. You’re basically agreeing that different flow cylinder to cylinder can benefit from a cam that address cylinder to cylinder differences.

If this was a class motor that had specific rules for intake manifolds, the answer is not use a different manifold. So is it snake oil? No it’s not. But if you go with an OTS camshaft that may not respond to the actual motors’ flow differences it’s junk.