Dual pattern cams...Black Magic or Legit?

[DSGcoupe]

eschaider- This is why I agreed in an earlier post about having a common plenum with tuned length (or equal length) runners. Design the ports/runners to work the same across the board, efficiency will follow (this I can prove from flow bench and dyno testing I have done over the years). I know there is a bit more science and math that goes into it though.

Gaz64- I had read that before which started my curiosity about how they may or may not work on a more street oriented motor. I can see the application in a CUP motor that runs 7k-8k for laps and laps, but had my doubts about a street motor that lives in the 2.5k - 5k area. Seemed like it was more of a pain than an asset.

1795 - I have a blue thunder weber manifold in the shop. Love the idea, but don't like not having filters on them where I live (middle of Corn fields). I have yet to find a solution that I liked how they looked. I may use it as a base for an idea I have floating around in my noggin however.

[eschaider]

Originally Posted by DSGcoupe

eschaider- This is why I agreed in an earlier post about having a common plenum with tuned length (or equal length) runners. Design the ports/runners to work the same across the board, efficiency will follow (this I can prove from flow bench and dyno testing I have done over the years). I know there is a bit more science and math that goes into it though ...

I wasn't attempting to rag on you, DSG. I was speaking to the Comp representations in the link to the Motor Trend article. I should have been more clear, my bad. If you are not a critical reader, the write-up sounds like the engine can produce more power with the four-pattern cam. In fact, it does, but not for the reasons nor at the levels the reader might intuitively attribute to the statement.

Because the airflow to the weak cylinders is reduced, they suffer a power reduction in two dimensions;

Dimension #1 Ve

Because the air flow to the cylinder is reduced by the compromised runner metrics for those four cylinders, The cylinder has less oxygen to use in burning (oxidizing) the fuel present. Less air means less horsepower. It is a linear 1:1 relationship.

Dimension #2 AFR

Because the cylinder has less air and relatively speaking, more fuel per unit of air, it will run rich. A rich tune is a lazy tune, down on power because of the overly rich mixture. If you find a way to correct the AFR for the air present in the cylinder, then you should expect an increase in power compared to the lazier, richer mixture that was previously made available.

Even though you may find a way to "normalize" the AFR with the other cylinders (hard with carbs much easier with sequential EFI) the "weak" cylinders will still be burning a smaller intake charge than the good cylinders. Anytime you burn less fuel and air you get less power — guaranteed.