Manifold heat cross over physics and benifits

krazykuda,
Yes, idling for 15 is not economy conducive. I should have mentioned that is not why I do it. I do it to warm up the oil, intake and entire engine.

Having block and oil fully warm ensures optimum lubrication to the top end. Having engine warm improves throttle response and 4 barrel response (my experience). When I hit the highway, I prefer optimum lube and power.