Originally Posted by dyn085
I would like to see dyno's showing a loss with a larger system. Typically, going larger will produce diminishing returns, but I can't imagine an actual loss, especially over stock. Our stock setup is right on the verge of 2" maximum flow capacity, so minow bolt-ons and tune would be on the verge of maxing out 2.25". I have nothing against either, I'm simply curious as to how 2.5" could dyno less than 2.25".
They were probably comparing it on a completely stock motor. I would venture to say that without airbox mods, the 2.5 killed too much backpressure and increased the pumping losses. You have seen that modding airflow makes the smaller exhaust a limiting factor, so going too large on the exhaust could make the smaller airflow a limiting factor. I have no doubt that the 2.5 produced more hp/tq vs. OEM, but it might not have outperformed the 2.25 vs. OEM