Thanks for posting up guys, we will get to the bottom of this,peoples first hand experiences are going to point us in the right direction.
optimal intake temperatures do exist..
I think I found some good info about commercial diesel motors and intake air temperatures.
This report on turbo diesel motors cannot stress enough how important it is to have intake air temperatures as close to the coolant temperature as possible. It may well be that in our diesel motors that great variation in coolant and intake air temperatures is hurting efficiency.
have a look at this informative and interesting
( if your a tech junkie) read on intake temperature of a turbo diesel.
http://www.mandieselturbo.de/files/n.../5510-0005.pdf
And Stan WOW that is encouraging and actually sounds like proof of the benefit.