heat

just discussed the heat that builds up in the engine bay with a pal who is involved with mechanical design...he said when cooling a hot space you enclose it (except for an entrance / exit) use an intake hole to match the biggest/fastest fan you can fit in and thereby create the largest draft possible into the space which needs cooling....any enlargment of the fan intake holes ie by fitting modified bumpers adding grills etc only reduces draft and the effect of cooling goes down with it...or to put it this way the worst way to cool your PC is to take the side panels off as the fan cant circulate a draft with no sides...or your bonnet if it was a car...however the calculation of extraction is complex with a car as cooling systems, weather and speed of travel come into play...but most designers over calculate the extremes with the initial design...so only increased performance needs increased intake...otherwise you're just adding to the heat by reducing draft...also rather perversely you dont want too much cooling as the efficiency of some moving parts is reliant on them being nice and hot

oh well back to the day job