Cooling fan on the hood??

[roman]

I've done the opposite, my car didnt come with those seals on the rear of engine bay / front of bonnet etc, so I've put them back in to make the radiator work better. (As I'm running a half width radiator that I'm trying to squeeze some reasonable efficiency out of)

Have also blanked off any hole into the engine bay apart from through the radiator and into the engine's air intake.

I'm also going to make up a tray underneath that only lets air out of the back of the engine bay.

Otherwise you get air entering the engine bay just after the radiator, when you want to keep it out as much as possible.

My car will probably get hotter at low speeds than one with a raise bonnet, but how long are you at low speeds when you're giving it a boot full, and need the full potential of your radiator?

Heat wrap on the exhaust is probably the most effective way to reduce under bonnet temperatures.

[Bean]

not sure about the exact physics but I thought the fast flowing air above the hood and windshield would create sufficient low pressure area to suck the heat of the engine bay away from the airvents if one has removed the rubber and/or raised the hood. This principle at least works efficient enough with airbrush/paintguns units that have a bottom mount paint reservoir