[Terry Syd]

Just to refresh your memory, we're talking about a diesel engine here (cetane).

So you're saying that the cooling effect and vaporisation is virtually immediate. That being the case, then a shorter run might allow a cooler intake charge as there will be less heat soak from additional plumbing in the engine bay. Although I'm at a loss to understand why there would be an additional couple of degrees drop in the intake temperature when the WI was injected pre-turbo.