(12-21-2020 )Rawze Wrote:  ...
- There are aftermarket intake manifolds (and CM570 factory manifolds) that fit the CM870 specifically out there that claim to be hi-flow. Those will have slight improvement above 500~ish HP due to the venturi circuit being cut out of the center of them or missing. They make zero difference below 500~+ hp though and require an egr-delete. The factory manifold has no flow restrictions below this point. For those with CM870's, they are deleted, and they are set above 500~ish horsepower, this is not a bad investment.

In Contrast to this though, NEWER engines like the CM871, and newer common rail engines, no aftermarket manifold has ever made a difference. This problem was essentially solved in the factory manifold. Non-factory manifolds however have some risk. This is because many of them are not designed to even out the distribution of intake air evenly to the cylinders like the factory unit does. This makes cylinders 5 and 6 run hotter than the rest, and imbalances the engine slightly. Therefore I am not a proponent of them in general on anything newer than a CM870... Just a warning.
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